The investigators used co-immunoprecipitation assays to identify BRD4 as an FBXO28-associated protein, then examined how the two molecules regulate transcription. FBXO28 mediated ubiquitination of BRD4 at lysine 395 through a lysine 63-linked conjugation model. Unlike ubiquitination processes that direct a substrate for destruction, this modification did not cause BRD4 degradation. Instead, it enhanced BRD4 activity as a transcriptional coactivator: changing FBXO28 expression altered the abundance of BRD4-target genes and affected BRD4 binding to the promoters of those genes.

The proposed downstream mechanism involves P-TEFb, a complex associated with transcriptional elongation. FBXO28-dependent ubiquitination of BRD4 facilitated activation of P-TEFb and subsequent phosphorylation of the serine 2 residue in the C-terminal domain of the largest subunit of RNA polymerase II. This phosphorylation was linked by the researchers to the initiation of transcription. The study therefore connects a ubiquitin-signaling event to changes in transcriptional programs that support the proliferation and movement of lung cancer cells.

The authors also described a positive feedback loop. BRD4 bound to the FBXO28 promoter, and increased FBXO28 transcription further strengthened the relationship between the two proteins. The experimentally supported model is that FBXO28 ubiquitinates BRD4, activated BRD4 increases FBXO28 expression, and elevated FBXO28 can reinforce BRD4 modification and activity. Overall, the work implicates the FBXO28–BRD4 feedback loop as a contributor to non-small cell lung cancer malignancy. Because the evidence comes from patient-sample associations and functional cellular experiments, the results indicate a promising research pathway rather than demonstrating an effective intervention or clinical benefit in people with lung cancer.

Subject of Research: FBXO28-mediated BRD4 ubiquitination and transcriptional activation in non-small cell lung cancer.

Article Title: FBXO28 promotes the malignancy of non-small cell lung cancer through ubiquitination-mediated activation of BRD4

Article References: Liang, Y., Jiao, Q., Zhang, F., Bai, W., Yang, J., Luo, X., Zhang, J., Tang, X., Tang, J., Zhang, Z., Yan, J., Lai, F., Sun, L., Cao, L., Zhang, W., & Lv, X.-B. (2026). FBXO28 promotes the malignancy of non-small cell lung cancer through ubiquitination-mediated activation of BRD4. Cell Death Discovery. https://doi.org/10.1038/s41420-026-03364-9

Image Credits: AI Generated

DOI: 10.1038/s41420-026-03364-9

Keywords: FBXO28, BRD4, non-small cell lung cancer, ubiquitination, transcription, P-TEFb, RNA polymerase II, cancer progression, positive feedback loop, promotes, malignancy, non-small

The study, published in Plant Molecular Biology on 20 October 2026, addresses a gap in the systematic characterization of deubiquitinases, or DUBs, in white birch. These enzymes remove ubiquitin from substrate proteins and form part of the ubiquitination–deubiquitination system, a key regulatory mechanism for maintaining proteome homeostasis in eukaryotic cells. DUBs regulate plant development, stress responses and other physiological processes, but their genomic characterization in this species has remained limited. This knowledge gap restricts understanding of their potential roles in reproduction in woody plants.

Using genome-wide analysis, the researchers identified 56 BpDUB genes in B. platyphylla. They divided the genes into six conserved subfamilies: UBP, OTU, UCH, MJD, JAMM and MINDY. Comparative and synteny analyses indicated that DUB genes are evolutionarily conserved across angiosperms while exhibiting lineage-specific divergence. The results therefore place the birch genes within a broadly shared angiosperm framework while also revealing characteristics that may distinguish them in the birch lineage.

The researchers examined promoters upstream of the BpDUB genes and found diverse cis-acting elements associated with growth and development, stress responses, hormone signalling and transcription-factor binding. These regulatory features identify possible routes through which individual DUB genes may respond to developmental and environmental signals. The presence of such elements does not by itself establish their activity in vivo, so the promoter analysis provides a framework for future experiments rather than a complete account of when or where each birch deubiquitinase is expressed or functions.

To test whether deubiquitination activity influences pollen development, the team treated pollen with PR-619. The treatment markedly impaired pollen germination and pollen-tube elongation, linking DUB activity with two central features of pollen development: the emergence of a germinating pollen grain and extension of its tube. Because PR-619 broadly inhibits deubiquitinases rather than selectively targeting BpUBP3, the experiment supports involvement of DUB activity generally and does not identify BpUBP3 as the sole enzyme responsible for the observed effects.

RNA sequencing provided more focused evidence for BpUBP3. The gene exhibited stage-specific induction during pollen germination, indicating that its expression changed as pollen progressed through this developmental stage. This pattern is consistent with a possible role in pollen development, although induction alone does not establish the function of the encoded protein. The researchers therefore combined the RNA-sequencing result with a targeted perturbation using an antisense oligonucleotide, or AS-ODN, to downregulate BpUBP3 and examine the consequences for pollen growth.

AS-ODN-mediated downregulation of BpUBP3 reduced pollen germination and pollen-tube growth. This finding strengthened the case for a functional contribution by the particular deubiquitinase because two complementary observations pointed in the same direction: BpUBP3 was induced in a stage-specific manner during germination, and reducing its expression impaired germination and tube extension. The targeted experiment narrows the interpretation of the broad inhibitor results, but it does not identify the complete range of BpUBP3 substrates or reveal every molecular step through which the protein influences pollen growth.

The findings position BpUBP3 within a larger network of plant regulation. The white birch genome contains 56 DUB genes belonging to six conserved subfamilies, while promoter sequences associate family members with growth, development, stress, hormone-signalling and transcription-factor pathways. The pollen experiments connect this genomic inventory to reproductive function. By combining family-wide identification, comparative and synteny analyses, promoter analysis, pharmacological inhibition, stage-specific transcript profiling and targeted gene downregulation, the researchers assembled several lines of evidence rather than relying on a single measurement.

Important limitations remain. The effects of PR-619 cannot be assigned exclusively to BpUBP3, and AS-ODN downregulation demonstrates a relationship between reduced BpUBP3 expression and impaired pollen performance without establishing every underlying mechanism. The source characterizes the findings as preliminary evidence and a basis for further investigation of DUB functions in reproductive development. The strongest supported conclusion is therefore specific: in white birch, BpUBP3 shows potential involvement in pollen germination and pollen-tube growth, while its direct targets and broader biological significance require further study.

Subject of Research: Genome-wide characterization of white birch deubiquitinases and the role of BpUBP3 in pollen development

Article Title: Genome-wide characterization of DUB genes in Betula platyphylla and BpUBP3 function in pollen tube growth

Article References: Wang, X., Zhao, C., Shi, J., Mei, Z., Jiang, Y., Shi, J., & Lan, X. (2026). Genome-wide characterization of DUB genes in Betula platyphylla and BpUBP3 function in pollen tube growth. Plant Molecular Biology, 116(6), Article 104. https://doi.org/10.1007/s11103-026-01770-2

Image Credits: AI Generated

DOI: 10.1007/s11103-026-01770-2

Keywords: Betula platyphylla, white birch, deubiquitinases, BpUBP3, pollen germination, pollen tube growth, ubiquitination, plant reproduction, RNA sequencing, functional genomics, Genome-wide, characterization

The study, led by Can Chen and colleagues at the Department of Hematology, School of Medicine, Affiliated Hangzhou First People’s Hospital, West Lake University, in collaboration with researchers at Wuhan Polytechnic University, was published in BMC Cancer. The research represents the first systematic investigation of how genes related to both ubiquitination and liquid-liquid phase separation (LLPS) contribute to the prognosis of patients with multiple myeloma, and it identifies UBA1 as a primary candidate biomarker for the disease.

Ubiquitination is a post-translational modification process in which the small protein ubiquitin is attached to target proteins, marking them for degradation by the proteasome or altering their localization and activity. This pathway is central to protein homeostasis, and its dysregulation has long been implicated in cancer development. Indeed, the proteasome inhibitor bortezomib, a cornerstone of multiple myeloma therapy, works by exploiting the cancer cell’s dependence on this very system. Liquid-liquid phase separation, on the other hand, is a physical process by which proteins and nucleic acids condense into membraneless organelles within cells, such as stress granules and nucleoli. This process has emerged as a critical regulator of gene expression, signal transduction, and cellular organization, and its disruption has been increasingly linked to tumor initiation and progression.

Despite growing evidence that both ubiquitination and LLPS play important roles in cancer biology, their combined contribution to multiple myeloma had not been systematically explored. The research team set out to fill this gap by identifying a set of genes — termed ubiquitination and liquid-liquid phase separation related genes, or ULLPSRGs — that are involved in both processes and that carry prognostic significance in multiple myeloma.

The researchers began by compiling a comprehensive list of genes associated with both ubiquitination and LLPS from publicly available databases and the scientific literature. They then analyzed gene expression data from multiple myeloma patients using large-scale genomic datasets, applying consistent clustering analysis and prognostic difference analysis to identify which of these genes were most closely associated with patient survival outcomes. Through this rigorous bioinformatic pipeline, the team identified four ULLPSRGs that were significantly associated with prognosis in multiple myeloma patients.

Using these four genes, the researchers performed consensus clustering analysis, which grouped patients into distinct molecular subtypes based on their expression patterns of the ULLPSRGs. The two identified clusters showed clear prognostic differences, suggesting that the activity of these genes can stratify patients into groups with different clinical outcomes. This finding underscores the potential of ULLPSRGs not just as individual biomarkers but as a coordinated molecular signature that captures biologically meaningful differences between tumors.

Building on this foundation, the team constructed a prognostic risk model using multivariate Cox regression, incorporating the expression levels of the four ULLPSRGs. The model was then validated on an independent dataset, confirming its predictive power. The signature emerged as an independent risk factor for multiple myeloma patients, meaning that its prognostic value held even when accounting for other established clinical variables. Importantly, the signature also correlated significantly with clinical factors, suggesting that it captures information that complements traditional staging and risk assessment tools.

To further understand the biological relevance of the ULLPSRG signature, the researchers conducted immune infiltration analysis, examining how the expression patterns of these genes related to the composition of immune cells within the tumor microenvironment. They found that the signature was significantly associated with the tumor microenvironment, suggesting that ubiquitination and LLPS-related genes may influence not only the intrinsic biology of myeloma cells but also their interactions with surrounding immune and stromal cells. This finding opens potential avenues for combining ULLPSRG-based prognostic stratification with immunotherapeutic approaches.

The team also performed enrichment analysis and drug sensitivity evaluation to explore the therapeutic implications of their findings. Enrichment analysis helps identify which biological pathways and processes are most active in patients with high versus low risk scores, providing clues about the molecular mechanisms driving poor outcomes. Drug sensitivity evaluation, meanwhile, assesses whether patients with different expression patterns of the ULLPSRGs might respond differently to existing therapies, potentially guiding personalized treatment decisions.

Perhaps the most clinically significant finding of the study came from the laboratory experiments. The researchers conducted cell experiments to confirm the functional role of UBA1, one of the four identified ULLPSRGs and the primary candidate biomarker highlighted in the study. UBA1 encodes the ubiquitin-activating enzyme E1, the enzyme that initiates the ubiquitination cascade by activating ubiquitin molecules before they are transferred to target proteins. When the researchers inhibited the expression of UBA1 in multiple myeloma cells, they observed two critical effects: the cells’ cycle progression was halted, and apoptosis — programmed cell death — was promoted. These results provide direct experimental evidence that UBA1 plays a functional role in supporting the survival and proliferation of myeloma cells, positioning it as a potential therapeutic target as well as a biomarker.

The identification of UBA1 as a central player in multiple myeloma biology is particularly noteworthy given the existing clinical context. Proteasome inhibitors like bortezomib and carfilzomib already target the downstream machinery of the ubiquitination pathway, and their success in treating myeloma validates the pathway as therapeutically actionable. However, resistance to proteasome inhibitors eventually develops in most patients, and targeting upstream components of the ubiquitination cascade — such as the E1 activating enzyme encoded by UBA1 — represents a potentially complementary strategy that could overcome or delay the emergence of resistance.

The study’s integration of liquid-liquid phase separation into the analysis adds an additional layer of biological insight. LLPS has been shown to regulate the formation of biomolecular condensates that concentrate specific proteins and nucleic acids, thereby controlling cellular processes ranging from transcription to DNA damage repair. In cancer, aberrant phase separation can contribute to the misregulation of tumor suppressors and oncogenes. By identifying genes that bridge both ubiquitination and LLPS, the researchers have highlighted a class of molecules that may coordinate protein degradation with spatial organization within the cell, offering a more nuanced understanding of how myeloma cells maintain their malignant state.

From a clinical perspective, the prognostic model developed in this study could provide oncologists with a powerful tool for risk stratification. By incorporating the expression levels of the four ULLPSRGs into a quantitative score, clinicians may be able to identify patients at higher risk of poor outcomes who might benefit from more aggressive or alternative therapeutic approaches. The fact that the model was validated on an independent dataset strengthens confidence in its generalizability, although further prospective validation in larger, more diverse patient cohorts will be necessary before clinical implementation.

The researchers also note that their findings could inform the development of novel therapeutic strategies. If UBA1 and the other ULLPSRGs are confirmed to play critical roles in myeloma cell survival through additional experimental studies, they could become targets for small-molecule inhibitors or other therapeutic modalities. The convergence of ubiquitination and LLPS biology in these genes suggests that disrupting their function could simultaneously impair multiple survival mechanisms that myeloma cells rely upon, potentially leading to more effective and durable treatments.

This study also exemplifies the growing power of integrative bioinformatics approaches in cancer research. By combining data from multiple genomic databases, applying sophisticated clustering and regression techniques, and validating findings through laboratory experiments, the researchers have demonstrated how computational analysis can generate testable hypotheses that translate into meaningful biological insights. The identification of ULLPSRGs as a previously unexplored class of prognostic markers in multiple myeloma illustrates the value of looking beyond traditionally studied pathways to uncover novel molecular determinants of cancer behavior.

As the field of multiple myeloma research continues to evolve, studies like this one that bridge fundamental cell biology with clinical outcomes are likely to play an increasingly important role. The identification of UBA1 as a primary candidate biomarker, along with the demonstration that its inhibition can halt cell cycle progression and promote apoptosis in myeloma cells, provides a compelling foundation for future research aimed at developing targeted therapies. With further validation and the development of pharmacological tools to modulate UBA1 activity, this finding could ultimately contribute to improved treatment strategies for patients battling this challenging disease.

Subject of Research: The role of ubiquitination and liquid-liquid phase separation related genes, particularly UBA1, in the prognosis and treatment of multiple myeloma.

Article Title: A study of ubiquitination and liquid-liquid phase separation related genes yields uba1 as a primary candidate biomarker for a role in multiple myeloma

Article References: Chen, C., Li, Y., Chen, Z., Shi, P., Li, Y., Qian, S., & Shan, L. (2026). A study of ubiquitination and liquid-liquid phase separation related genes yields uba1 as a primary candidate biomarker for a role in multiple myeloma. BMC Cancer. https://doi.org/10.1186/s12885-026-16899-y

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16899-y

Keywords: multiple myeloma, UBA1, ubiquitination, liquid-liquid phase separation, biomarker, prognosis, tumor microenvironment, apoptosis, cell cycle, proteasome inhibitors, bioinformatics, hematologic malignancy

Protein arginine methylation is carried out by a family of enzymes called protein arginine methyltransferases, or PRMTs. These enzymes transfer methyl groups onto the nitrogen atoms of arginine residues, generating distinct chemical outcomes depending on the enzyme involved. Type I PRMTs produce asymmetric dimethylarginine marks, type II enzymes generate symmetric dimethylation, and type III and type IV PRMTs add monomethyl or terminal methyl modifications respectively. The substrates are remarkably diverse. PRMTs decorate histones, the spool-like proteins around which DNA is wound, thereby shaping gene expression programs, but they also modify a vast array of nonhistone proteins, altering their enzymatic activity, their ability to bind partner molecules, their subcellular localization and, crucially for the story told in this review, their recognition by the protein degradation machinery.

Ubiquitination is the second half of the dialogue. In this process, the small 76-amino-acid protein ubiquitin is attached to lysine residues on target proteins through a cascade involving an activating enzyme, a conjugating enzyme and, most importantly for specificity, a ubiquitin ligase known as an E3. Depending on how ubiquitin chains are assembled and linked, the consequence can be proteasomal destruction of the tagged protein or, alternatively, a non-degradative change in trafficking, interaction or activity. Deubiquitinases, the enzymes that remove ubiquitin marks, add a further layer of reversibility. Together, methylation and ubiquitination therefore represent two of the most versatile post-translational modification systems in the cell, and the review’s central thesis is that they constantly influence one another rather than operating on separate tracks.

The crosstalk runs in both directions. In one direction, arginine methylation can change how readily a protein is recognized by E3 ubiquitin ligases. Methylation of an arginine residue can mask or reshape the local surface of a protein, sometimes blocking the docking of a ligase and thereby protecting the protein from ubiquitination and degradation. In other contexts, the same chemical mark does the opposite: it creates or exposes a recognition element that recruits the ubiquitination machinery, accelerating the destruction of the tagged protein. This means a single methylation event can function as either a stabilizing shield or a degradation signal, depending on the protein and the cellular setting, a context dependence that the authors identify as one of the field’s central challenges.

The reverse direction is equally consequential. E3 ubiquitin ligases and deubiquitinases can act directly on the PRMT enzymes themselves, controlling their abundance, stability and, by extension, the overall methylation landscape of the cell. When a ligase tags a PRMT for proteasomal degradation, the methyl marks that enzyme would have deposited begin to fade, changing the fate of dozens of downstream substrates. Conversely, when deubiquitinases rescue a PRMT from degradation, methylation-dependent signaling is sustained or amplified. The result is a feedback architecture in which each system tunes the other, creating what the authors describe as a dynamic, bidirectional network rather than a simple linear pathway.

What makes this network medically important is its reach into nearly every hallmark of cancer. The review connects methylation-ubiquitin crosstalk to tumor invasion and metastasis, to the uncontrolled proliferation of malignant cells, to apoptosis, the programmed cell death that many therapies try to trigger, and to ferroptosis, an iron-dependent form of cell death that has become a major focus of cancer research. It also implicates the network in DNA repair and the maintenance of genomic stability, in the metabolic reprogramming that allows tumors to fuel their growth, in the acquisition of drug resistance and in immune escape, the process by which cancer cells avoid detection by cytotoxic T cells and other immune effectors. By determining whether key signaling proteins are stabilized or destroyed, the crosstalk effectively sets the gain on the molecular circuits that govern how cancer cells grow, move, survive stress and respond to treatment.

The therapeutic implications are considerable. PRMT inhibitors have already entered clinical development for several malignancies, and the review argues that understanding the ubiquitination dimension of PRMT biology could explain why single-agent approaches sometimes fall short and how resistance emerges. If methylation protects an oncogenic protein from degradation, then blocking the methyltransferase should destabilize that protein; if ubiquitination destroys a tumor suppressor only after it has been methylated, then the therapeutic logic inverts. The authors highlight several forward-looking strategies, including dual-function inhibitors designed to hit both modification systems at once, small-molecule degraders that exploit the ubiquitin-proteasome machinery to eliminate disease-driving proteins, and engineered nanobodies that could be tailored to disrupt specific methylation-dependent recognition events. They also point to combination approaches in which modulation of the methylation-ubiquitin network is paired with immune checkpoint blockade, with the goal of making tumors more visible to the immune system while simultaneously undermining their survival circuits.

The authors are careful to emphasize the obstacles. The crosstalk is highly context-dependent: the same methylation event can stabilize one protein and destabilize another, and the same ligase can behave as an oncogene in one tumor type and a tumor suppressor in another. Mapping these relationships across dozens of PRMT substrates and hundreds of E3 ligases will require systematic approaches, including proteomics methods that can simultaneously read methylation and ubiquitination states on the same molecules. Achieving therapeutic precision is a second challenge, since both PRMTs and ubiquitination enzymes have many normal physiological roles, and indiscriminate interference risks toxicity. The review frames these difficulties not as reasons for pessimism but as a research agenda, identifying the mapping of context-specific crosstalk nodes as a priority for the field.

For readers following the broader post-translational modification literature, the review situates arginine methylation within a family of cross-regulated marks that increasingly includes phosphorylation, acetylation and O-GlcNAcylation, each of which has been shown to influence protein stability in ways analogous to the mechanisms described here. What distinguishes the methylation-ubiquitin axis is the depth of its documented involvement in cancer-relevant pathways and the growing availability of chemical tools to probe it. As PRMT inhibitors mature clinically and as degrader technologies expand, the points of contact between these two systems are likely to become some of the most closely watched nodes in cancer pharmacology.

The review, Protein arginine methylation and ubiquitination: A prominent crosstalk and its functions in cancer, was published in Genes & Diseases, a peer-reviewed journal focused on the molecular bases of human disease. Its synthesis suggests that the next phase of work will move from cataloging individual methylation-ubiquitin pairs to modeling the network as a whole, with the aim of predicting how a given tumor will respond when one arm of the dialogue is therapeutically silenced. If that predictive understanding can be achieved, the molecular conversation between arginine methylation and ubiquitination may shift from an object of study to a set of actionable targets in the clinic.

Subject of Research: Crosstalk between protein arginine methylation and ubiquitination in cancer biology and therapy

Article Title: Decoding a molecular dialogue: How arginine methylation and ubiquitination shape cancer

Article References: Decoding a molecular dialogue: How arginine methylation and ubiquitination shape cancer. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: arginine methylation, ubiquitination, PRMT, post-translational modification, cancer, E3 ubiquitin ligase, deubiquitinase, ferroptosis, drug resistance, immune escape, proteasome, Genes & Diseases

Acute kidney injury, or AKI, affects millions of patients worldwide each year, particularly those undergoing major surgery, suffering from severe infections, or exposed to kidney-toxic drugs. Despite its prevalence, there are no specific drugs that halt the underlying inflammatory damage. The new study offers a potential solution by targeting a previously unknown mechanism. The researchers found that RNF130 is significantly downregulated in both mice and patients suffering from AKI, suggesting that its loss is not a side effect of kidney damage but a central driver of it. This observation immediately raised the question of what RNF130 does inside macrophages and why its absence makes the inflammatory response so much worse.

To answer this, the team used genetic tools to delete RNF130 specifically in myeloid cells, the family of immune cells that includes macrophages. In mouse models of AKI, this targeted loss aggravated pathological damage to the kidneys and facilitated macrophage pyroptosis. Pyroptosis is a form of programmed cell death that is inherently inflammatory: unlike quiet apoptosis, pyroptotic cells rupture and spill their contents, including damage-associated molecular patterns, into the surrounding tissue. This triggers a feedback loop in which more immune cells are recruited, more pyroptosis occurs, and tissue destruction accelerates. By showing that myeloid-specific RNF130 loss worsens this process, the researchers established that the protein acts as a brake on inflammatory cell death within the immune compartment itself.

The next challenge was to identify the molecular target that RNF130 controls. Using proteomics analyses combined with experimental validation, the team discovered that RNF130 deficiency prevents the ubiquitination of a protein called programmed cell death 4, or PDCD4. Ubiquitination is the process by which cells tag proteins for destruction by the proteasome, the cellular waste-disposal system. RNF130 is a ring finger protein, a class of enzymes that transfers ubiquitin onto target proteins. When RNF130 is present, it tags PDCD4 with ubiquitin at a specific site, lysine 402, ensuring that PDCD4 is degraded and kept at low levels. When RNF130 is absent, PDCD4 escapes this destruction and accumulates inside macrophages, where it sets off a chain reaction that leads to pyroptosis.

The downstream effects of PDCD4 accumulation are technically elegant. Activated PDCD4 promotes the phosphorylation of two key transcription factors, NF-κB and STAT3. Phosphorylation activates these proteins, allowing them to enter the nucleus and drive the expression of inflammatory genes. Among the genes activated by this pathway is NLRP3, a central component of the inflammasome, a multi-protein complex that assembles inside cells in response to danger signals. Once the NLRP3 inflammasome is activated, it triggers caspase-1, an enzyme that cleaves gasdermin D, or GSDMD. Cleaved GSDMD forms pores in the cell membrane, causing the cell to swell and rupture. This is the final step of pyroptosis. The researchers showed that overexpression of PDCD4 nullifies the beneficial role of RNF130, confirming that PDCD4 is the critical downstream effector through which RNF130 exerts its protective effects.

This mechanistic chain, from RNF130 to ubiquitination of PDCD4 at lysine 402, to phosphorylation of NF-κB and STAT3, to NLRP3 inflammasome activation, to caspase-1-mediated cleavage of GSDMD, represents a complete signaling pathway that had not been described before in the context of kidney injury. Each step was validated experimentally, and the pathway was shown to operate specifically in macrophages rather than in kidney epithelial cells. This specificity is important because it means that therapeutic interventions targeting RNF130 would act on the immune response rather than directly on kidney tissue, potentially avoiding unwanted effects on the kidney cells themselves.

The most exciting aspect of the study, however, came from a high-throughput screening of a compound library. The researchers searched for molecules that could upregulate RNF130 and thereby restore the protective brake on macrophage pyroptosis. They identified Nystose, a compound that effectively mitigated renal injury in ischemic AKI mice by targeting and upregulating RNF130. Nystose is a fructooligosaccharide, a type of short-chain carbohydrate found naturally in certain plants. The finding that a natural compound can restore RNF130 levels and protect the kidneys opens a potential path toward drug development. Because Nystose acts by upregulating RNF130 rather than by directly inhibiting any single downstream molecule, it may offer a more physiological approach to treatment.

The study was conducted exclusively in male mice, which is an important limitation. Biological responses to inflammation and pyroptosis can differ between sexes, and the researchers note in the title that the findings apply to male mice. Whether RNF130 operates through the same pathway in female mice or in human patients of both sexes remains to be determined. Additionally, while the study showed that RNF130 is downregulated in patients with AKI, the therapeutic experiments were performed in mice. Translating these findings into clinical treatments will require further studies to confirm that upregulating RNF130 in human macrophages produces the same protective effects and that compounds like Nystose can be safely administered to patients at risk of kidney injury.

Despite these caveats, the study represents a significant advance in understanding how immune cells contribute to kidney damage. By identifying RNF130 as a central regulator of macrophage pyroptosis and PDCD4 as its critical substrate, the researchers have provided a new molecular target for drug development. The finding that Nystose can upregulate RNF130 and protect against ischemic AKI offers immediate potential for repurposing existing compounds. The work also highlights the value of proteomics-based approaches for discovering previously unknown signaling pathways. As the field of AKI research moves toward targeted therapies, the RNF130-PDCD4 axis may become a focal point for interventions designed to calm the inflammatory storm that destroys kidney tissue in vulnerable patients.

Subject of Research: How the ubiquitin ligase RNF130 restrains macrophage pyroptosis in acute kidney injury through degradation of PDCD4

Article Title: RNF130 ameliorates renal injury and inflammation by inhibiting macrophage pyroptosis through ubiquitination degradation of PDCD4 in male mice

Article References: Zhu, X.-X., Zhang, A.-Y., Yang, L., Wen, Y.-Y., Wei, M., Xu, G.-W., Liu, M.-H., Gao, S.-Q., Zhuang, Y.-Y., Li, H.-D., Bao, N., Ghashghaeinia, M., Lang, F., Xiong, S.-P., Li, X., Zheng, G.-L., Lu, Q.-B., & Sun, H.-J. (2026). RNF130 ameliorates renal injury and inflammation by inhibiting macrophage pyroptosis through ubiquitination degradation of PDCD4 in male mice. Nature Communications. https://doi.org/10.1038/s41467-026-78398-9

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78398-9

Keywords: acute kidney injury, macrophage pyroptosis, RNF130, PDCD4, NLRP3 inflammasome, ubiquitination, Nature Communications, Nystose, ameliorates, renal, injury, inflammation

The enzyme at the center of the story is lactate dehydrogenase A, or LDHA, the workhorse protein that converts pyruvate into lactate at the end of the glycolytic pathway. In many tumors, LDHA activity allows cells to keep producing energy even when oxygen is scarce, a metabolic mode reminiscent of fermentation. It also generates lactate, a molecule that tumors exploit as a signaling agent and as a building block for chemical modifications on histone proteins. Yet for all its importance, the mechanisms that keep LDHA protein stable inside colorectal cancer cells have remained poorly charted. The new study set out to fill that gap by asking a deceptively simple question: what protects LDHA from being destroyed?

To answer it, the researchers turned to affinity purification followed by mass spectrometry, a technique that fishes out the proteins that physically associate with a molecule of interest. Among the partners they captured was TRIP13, an AAA+ ATPase, a member of a family of ring-shaped motor proteins that use the energy of ATP hydrolysis to remodel other proteins. TRIP13 is already known to cancer biologists for its role in spindle assembly checkpoint signaling and in the repair of meiotic recombination intermediates, and elevated TRIP13 levels have been linked to poor outcomes in several tumor types. The mass spectrometry data suggested something unexpected: TRIP13 was not just a casual acquaintance of LDHA but a genuine binding partner, a result the team confirmed using co-immunoprecipitation experiments.

The functional consequences of that partnership proved striking. When the researchers depleted TRIP13 from colorectal cancer cells, LDHA protein abundance collapsed and the remaining LDHA became far less stable, while the amount of ubiquitin attached to LDHA rose sharply. Notably, the levels of LDHA messenger RNA barely changed, indicating that TRIP13 was acting after the gene had been read, at the level of protein degradation rather than protein production. In other words, TRIP13 was not telling the cell to make more LDHA; it was preventing the cell from throwing LDHA away.

The destruction pathway that TRIP13 blocks turned out to be mediated by FBXW7, a well-characterized substrate-recognition component of the SCF ubiquitin ligase complex. FBXW7 acts as a quality-control scout, binding specific sequence motifs on target proteins and tagging them for delivery to the proteasome, the cellular garbage disposal. FBXW7 is famous as a tumor suppressor, and its loss is common in many cancers, but the new work reveals a metabolic dimension to its activity: it can tag LDHA for degradation. TRIP13, the researchers found, competes with FBXW7 for access to LDHA. By occupying the enzyme, TRIP13 limits FBXW7 association, suppressing FBXW7-dependent ubiquitination and the subsequent proteasomal destruction of LDHA. Experiments with purified proteins provided direct evidence for this competition, showing that the two molecules vie for the same binding surface on LDHA rather than acting through intermediaries.

The binding interface itself carries mechanistic weight. TRIP13 attaches to LDHA through its AAA+ ATPase-associated region, and the team engineered a mutant lacking this domain, TRIP13-ΔAAA+, to test whether the physical connection was essential. It was. Wild-type TRIP13 could stabilize LDHA and sustain the metabolic program, while the binding-defective mutant could not. This mutant-based approach transformed the study from correlation into causation: the protective effect on LDHA required the physical handshake between the two proteins, not some indirect influence of TRIP13 on cell state.

What does stabilized LDHA actually buy a tumor cell? Quite a lot, it turns out, especially under hypoxia. When TRIP13 was present, colorectal cancer cells maintained glycolytic activity and lactate production even when oxygen was scarce, a capacity the authors describe as glycolytic plasticity, the ability to keep the fermentative metabolic mode running under stress. When TRIP13 was removed, LDHA levels fell, glycolysis weakened, and the cells became flooded with oxidative stress, the damaging accumulation of reactive oxygen species that hypoxic cells normally manage with elaborate antioxidant defenses. The loss of TRIP13 also made the cells dramatically more sensitive to oxaliplatin, one of the standard chemotherapy drugs for colorectal cancer, which works in part by generating oxidative damage.

The rescue experiments revealed the logic of the pathway with unusual clarity. Restoring LDHA, supplementing the cells with lactate, or depleting FBXW7 all partially rescued the vulnerabilities created by TRIP13 loss, confirming that the TRIP13–LDHA–FBXW7 axis is the operative circuit. The lactate connection opened an even more intriguing chapter. Elevated lactate, the team found, fuels a p300-dependent program of histone lactylation, a chemical modification in which lactate-derived groups attach to histone proteins and alter gene expression. Specifically, lactylation of histone H3 at lysine 18, abbreviated H3K18la, promoted the expression of antioxidant genes including GCLC, which encodes a subunit of the glutathione synthesis machinery, and SLC7A11, a component of the cystine transport system that supports glutathione production. In essence, the lactate produced by stabilized LDHA does not merely sit in the cell as metabolic waste; it becomes a signal that reprograms gene expression to build the cell’s antioxidant armor.

The pharmacological and genetic tests of p300 reinforced this epigenetic arm of the pathway. When p300 activity was blocked, either with drugs or by genetic means, the lactate-driven antioxidant program weakened, confirming that the histone-modifying enzyme p300 is the conduit through which lactate translates into defensive gene expression. The team then took the story into living animals, using xenograft models in which human colorectal cancer cells are implanted in mice. Consistent with the cell-based findings, tumors expressing wild-type TRIP13 grew robustly, while those carrying the LDHA-binding-defective TRIP13-ΔAAA+ mutant failed to sustain the metabolic program, demonstrating that the physical TRIP13–LDHA interaction underpins tumor growth in vivo.

The therapeutic implications are considerable. Colorectal cancer remains one of the most common malignancies worldwide, and resistance to oxaliplatin-based chemotherapy is a major barrier to curative treatment. The new study suggests that TRIP13-dependent LDHA stabilization is a central mechanism by which tumor cells maintain redox homeostasis, the balance between oxidative damage and antioxidant defense, under hypoxic stress, and that this same mechanism underlies chemoresistance. Targeting the TRIP13–LDHA interaction, or the downstream lactate–p300–H3K18la antioxidant program, could therefore strip tumor cells of the metabolic flexibility they need to survive treatment. The work also adds a metabolic twist to the biology of FBXW7, a tumor suppressor whose substrate-recognition activity now includes a key glycolytic enzyme. As with any preclinical study, the path from xenograft models to patients will require further validation, and the tools to disrupt the TRIP13–LDHA handshake in humans are still under development. But the study provides a detailed molecular map of how colorectal cancer cells guard their metabolic machinery, and it identifies a specific, druggable-looking circuit whose disruption could resensitize chemoresistant tumors to standard therapy.

Subject of Research: TRIP13-mediated stabilization of LDHA against FBXW7-dependent ubiquitination and its role in glycolytic plasticity and oxaliplatin resistance in colorectal cancer

Article Title: TRIP13 protects LDHA from FBXW7-mediated degradation and drives glycolytic plasticity in colorectal cancer

Article References: Sheng, N., He, Q., Wang, J., Zhou, S., Gu, Y., Gong, J., He, P., Chen, H., & Wang, Z. (2026). TRIP13 protects LDHA from FBXW7-mediated degradation and drives glycolytic plasticity in colorectal cancer. Journal of Experimental & Clinical Cancer Research. https://doi.org/10.1186/s13046-026-03858-5

Image Credits: AI Generated

DOI: 10.1186/s13046-026-03858-5

Keywords: TRIP13, LDHA, FBXW7, ubiquitination, glycolysis, lactate, H3K18 lactylation, oxaliplatin resistance, colorectal cancer, cancer metabolism, hypoxia, proteostasis

CYLD belongs to a family of enzymes known as deubiquitinases, or DUBs. To understand what these enzymes do, it helps to think of ubiquitin as a small molecular tag that cells attach to proteins. Depending on how the tags are chained together, they can signal that a protein should be destroyed, that it should change location, or that it should participate in a signaling cascade. DUBs are the scissors that snip these tags off, reversing the process. CYLD is a member of the ubiquitin-specific protease subfamily, the largest class of DUBs, and it specializes in removing two particular types of ubiquitin chains: those linked through lysine 63 and those linked head-to-tail through methionine 1, known as linear chains. Both chain types are heavily used in inflammatory signaling, which explains why CYLD sits at the heart of so many cellular decisions.

Structurally, CYLD is unusual among its relatives. It carries three CAP-Gly domains at its N-terminus, which anchor it to microtubules and to signaling partners, and a large catalytic USP domain at its C-terminus. Crystallographic and biochemical work has revealed that CYLD lacks a subdomain called the Fingers region that most other USPs use to grip the end of a ubiquitin chain. This absence is not a defect but an adaptation: it allows CYLD to cut in the middle of lysine 63 and linear chains rather than only at their tips, giving it a kinetic advantage over enzymes that must nibble from the outside in. Subtle differences in its active site, particularly an extended loop between two beta strands, explain why CYLD strongly prefers lysine 63 chains and is essentially inactive against lysine 48 chains, the type that usually marks proteins for destruction by the proteasome.

Embedded within the catalytic domain is another oddity: a small zinc-binding module resembling a B box, a structure more commonly found in E3 ligases, the enzymes that attach ubiquitin rather than remove it. Experiments with recombinant CYLD lacking this region showed that the B box is dispensable for catalytic activity and does not bind ubiquitin itself. Instead, it appears to serve two other purposes: it mediates dimerization of CYLD molecules and helps retain the enzyme in the cytoplasm. Mutants lacking the B box partially drift into the nucleus, suggesting that this small module acts as a kind of cytosolic anchor. Meanwhile, the CAP-Gly domains do double duty. The first two bind microtubules, while the third interacts with NEMO, a regulatory subunit of the IKK complex that sits at the center of the NF-κB pathway, and is essential for full enzymatic activity in vitro.

CYLD’s most famous role is as a brake on NF-κB, a transcription factor that drives inflammation, cell survival, and immune responses. When tumor necrosis factor (TNF) binds its receptor on the cell surface, a signaling complex assembles that includes RIPK1, TRAF2, and the LUBAC complex, which decorates the assembly with linear ubiquitin chains. CYLD is recruited to this complex through its partner SPATA2 and begins trimming the ubiquitin tags. If NF-κB remains active, the cell survives and divides. But if NF-κB is repressed, a secondary complex forms containing caspase-8, which triggers apoptosis, the orderly form of cell death. If caspase-8 is absent or inhibited, RIPK1 instead pairs with RIPK3 to activate MLKL, a pore-forming protein that causes necroptosis, an inflammatory type of cell death. By removing ubiquitin from RIPK1, CYLD tips the balance toward these death pathways, acting as a kind of molecular referee between life and death.

But CYLD’s influence extends well beyond apoptosis and necroptosis. Recent work has shown that it also restrains pyroptosis, a lytic and highly inflammatory form of cell death triggered by infection and cellular stress. In macrophages, CYLD deubiquitinates PLK4 to limit the activity of the NLRP3 inflammasome, a molecular machine that ignites pyroptosis. In breast cancer cells, hypoxia drives the RNF213-mediated ubiquitination and degradation of CYLD, which in turn permits NF-κB-driven expression of NLRP3 and, together with endoplasmic reticulum stress, triggers pyroptotic death. CYLD has also been implicated in ferroptosis, an iron-dependent form of cell death, through its effects on the YAP protein in prostate cancer cells. The enzyme’s dual role in either promoting or restraining different death modalities depends on its interactions, its modifications, its location within the cell, and the specific signal it receives.

Central to all of this is SPATA2, a partner protein identified in 2016 by four independent groups using mass spectrometry. SPATA2 binds CYLD through complementary domains and simultaneously connects it to the LUBAC complex via an interaction with HOIP. This bridging function recruits CYLD to the TNF receptor signaling complex and to other immune signaling platforms. In vitro, SPATA2 enhances CYLD’s enzymatic activity against both linear and lysine 63 chains, and cells lacking SPATA2 show increased ubiquitination of CYLD’s substrates. SPATA2 also competes with another DUB called OTULIN for binding to HOIP, balancing the overall activity of the LUBAC. Mice lacking both SPATA2 and CYLD develop uncontrolled inflammation and die perinatally, underscoring how tightly these two proteins cooperate to keep immune signaling in check.

Perhaps the most fascinating layer of regulation comes from post-translational modifications, chemical tags that alter CYLD’s behavior without changing its genetic sequence. Phosphorylation, the addition of phosphate groups to serine or threonine residues, is the best studied. CYLD carries a cluster of phosphorylation sites between its second and third CAP-Gly domains, with serine 418 being a particularly important target. This residue is phosphorylated in response to a wide range of stimuli, including TNF, bacterial products, antigen receptor engagement, and constitutively in some aggressive blood cancers. The kinases responsible include the canonical IKKβ and the noncanonical TBK1 and IKKε. Intriguingly, the consequences of phosphorylation are disputed: some studies report that it dampens CYLD’s activity, promoting cell survival in T-cell leukemia, while others find that it enhances the enzyme’s ability to trim lysine 63 chains. A recent mass spectrometry analysis identified six phosphorylation sites in TNF-stimulated cells, five of which fall within the phospho-patch, suggesting that multiple modifications may act in concert rather than in isolation.

CYLD is also itself a target of ubiquitination, a poetic irony for an enzyme that spends its life removing ubiquitin from others. The E3 ligase SCFβ-TRCP ubiquitinates CYLD and reduces its abundance, a process that requires prior phosphorylation and plays a role in osteoclast differentiation. Another E3 ligase, MIB2, decorates CYLD with lysine 48 chains at two specific lysines, driving its proteasomal degradation and thereby amplifying NF-κB signaling in response to TNF. In hypoxic tumors, RNF213 ubiquitinates both CYLD and SPATA2, targeting them for lysosomal degradation and initiating pyroptotic cell death. Beyond ubiquitin, CYLD is modified by SUMOylation, the attachment of small ubiquitin-like modifiers. In neuroblastoma cells and glioblastoma stem-like cells, SUMOylation at lysine 40 impairs CYLD’s catalytic activity, leading to hyperactivation of NF-κB and, in the case of glioblastoma, promoting an aggressive phenotypic transition of the tumor cells.

Finally, CYLD can be irreversibly cut by proteases, a modification that permanently alters its function. Caspase-8 cleaves CYLD at aspartic acid 215 following TNF stimulation, inactivating the enzyme and blocking necroptosis in fibroblasts and macrophages. During influenza A virus infection, caspase-8-mediated cleavage of CYLD enhances innate antiviral immunity by preventing the deubiquitination of signaling proteins. The paracaspase MALT1, a caspase-like enzyme central to lymphocyte activation, cuts CYLD at arginine 324 in T cells, in aggressive B-cell lymphomas, and in glioblastoma stem cells, generally silencing the enzyme and promoting cell survival. Remarkably, recent work suggests that the N-terminal fragment released by caspase-8 cleavage is secreted into the bloodstream and may serve as a biomarker of septic shock. As the Nantes authors emphasize, mapping the complete landscape of CYLD’s modifications, understanding how they interact hierarchically, and exploring their interplay with SPATA2 represent the next great challenges for researchers hoping to exploit this remarkable enzyme therapeutically.

Subject of Research: Post-translational modifications regulating the deubiquitinating enzyme CYLD in cell death and inflammation

Article Title: The good, the bad, and the modified: CYLD’s post-translational tale

Article References: Macé, Y. M., Bidère, N., & Douanne, T. (2025). The good, the bad, and the modified: CYLD’s post-translational tale. Frontiers in Cell Death, 4, Article 1583221. https://doi.org/10.3389/fceld.2025.1583221

Image Credits: AI Generated

DOI: 10.3389/fceld.2025.1583221

Keywords: CYLD, deubiquitinase, post-translational modifications, NF-κB signaling, cell death, apoptosis, necroptosis, pyroptosis, SPATA2, phosphorylation, ubiquitination, tumor suppressor

Post-translational modifications, or PTMs, are biochemical edits applied to proteins after translation. Phosphorylation, ubiquitination, acetylation, methylation, SUMOylation, O-GlcNAcylation, and poly-ADP-ribosylation each alter a protein’s behavior in distinct ways. A phosphate group can switch an enzyme on or off. A ubiquitin chain can mark a transcription factor for destruction. An acetyl group can change where a protein sits inside the cell or whom it binds to. The review’s central claim is that these modifications do not merely fine-tune bone biology; they act as a networked control system that gates, amplifies, and dampens the signals flowing through pathways such as Wnt, BMP, RANKL, Notch, and Hedgehog, which orchestrate the activity of osteoblasts, osteoclasts, and osteocytes.

The authors organize the evidence around three conceptual pillars. The first is bidirectionality: PTMs and classical signaling pathways do not operate in a one-way hierarchy but feed back into each other. Signaling cascades recruit enzymes that modify target proteins, while those modified proteins in turn alter the intensity, duration, and spatial distribution of the signals themselves. The second pillar concerns functional modes. Some PTM events act as gates, holding a pathway silent until a specific cue arrives. Others amplify a weak signal into a robust cellular response, or dampen an overactive pathway to prevent runaway bone resorption. The third pillar is spatiotemporal regulation: the same modification can have different consequences depending on which cell type carries it, in which subcellular compartment it occurs, and at which stage of development, aging, or disease it appears.

Osteoblasts, the bone-forming cells derived from mesenchymal stem cells, illustrate the stakes. Their differentiation depends on transcription factors such as RUNX2 and Osterix, whose activity and stability are controlled by phosphorylation and ubiquitination. Glycogen synthase kinase 3 beta, a well-known kinase, phosphorylates beta-catenin in the Wnt pathway and tags it for degradation, thereby suppressing osteoblast differentiation. When GSK3β itself is phosphorylated at an inhibitory site, beta-catenin accumulates and drives bone formation. The review emphasizes that such regulatory loops are not isolated curiosities but recurring motifs: the same kinase or ligase can be repurposed by different PTM events to produce opposite outcomes depending on context.

Osteoclasts, the bone-resorbing cells, are governed by an equally dense PTM web. The RANKL signaling cascade, which drives osteoclast differentiation and activation, depends on phosphorylation events that propagate signals from the cell surface to the transcription factor NFATc1, the master regulator of osteoclast identity. Ubiquitination and deubiquitination of signaling intermediates determine whether the response is sustained or extinguished. Cathepsin K, the protease that dissolves bone matrix, is itself subject to regulatory processing. The review highlights that dysregulated PTM events in osteoclasts contribute directly to pathological bone loss in osteoporosis and inflammatory conditions such as rheumatoid arthritis, where tumor necrosis factor alpha and interleukin-6 reshape the modification landscape of signaling proteins.

Osteocytes, the embedded mechanosensory cells that make up the vast majority of bone cells, add another layer of complexity. These cells sense mechanical loading and orchestrate remodeling by secreting molecules such as sclerostin and RANKL. The review notes that PTMs regulate osteocyte function through modifications of proteins involved in mechanotransduction, the process by which physical force is converted into biochemical signals. O-GlcNAcylation, the attachment of N-acetylglucosamine sugars to proteins by the enzyme OGT and their removal by OGA, emerges as a nutrient-sensitive modification that links cellular metabolism to bone cell behavior. Histone acetylation and methylation, mediated by histone acetyltransferases and deacetylases, control the accessibility of genes required for osteocyte survival and communication within the bone matrix.

The pathological implications are substantial. The review connects dysregulated PTMs to osteoporosis, osteoarthritis, metabolic bone diseases, inflammatory bone loss, and impaired fracture repair. In osteoarthritis, modifications of cartilage and subchondral bone proteins alter the balance between matrix degradation and synthesis. In senescence-associated conditions, PTMs influence the secretory phenotype of aging skeletal cells, which promotes local inflammation and tissue degeneration. Poly-ADP-ribosylation, a modification involved in DNA damage responses, appears in the context of oxidative stress and cell death in bone cells. Peptidylarginine deiminase enzymes, which convert arginine residues to citrulline, are implicated in inflammatory joint disease and may influence bone erosion. Each of these connections points to PTM enzymes as potential therapeutic targets, though the review is careful to note that causality remains unproven for many site-specific events.

That caution is one of the review’s most valuable contributions. The authors acknowledge that evidence is uneven across PTM types and skeletal cell populations. Phosphorylation is well characterized in osteoblast and osteoclast signaling, but less-studied modifications such as SUMOylation, neddylation, and lactylation remain poorly mapped in bone. Many reported PTM events are correlational rather than causal; showing that a modification is present in a disease state does not prove it drives the pathology. Distinguishing which of the thousands of possible modification events actually control bone homeostasis requires targeted mutagenesis of specific modification sites, cell-type-specific deletion of modifying enzymes, and quantitative proteomics that can track modification dynamics over time and across compartments.

Emerging technologies are beginning to close these gaps. Quantitative PTM proteomics now allows researchers to measure thousands of modification events simultaneously and compare their abundance between healthy and diseased bone. Single-cell RNA sequencing and spatial transcriptomics reveal which cell populations carry which modification machinery, resolving the heterogeneity that bulk assays obscure. Multi-omics integration, combining proteomics, transcriptomics, epigenomics, and metabolomics, offers a systems-level view of how PTM networks interact with metabolic state and gene expression. The review argues that these tools, combined with classical genetics and pharmacology, will be essential for identifying which PTM events are true regulatory nodes rather than passive consequences of cellular state.

The broader significance of the review lies in its reframing of bone biology as a networked control problem rather than a linear cascade of pathways. Just as engineers design control systems with sensors, actuators, and feedback loops, skeletal cells deploy PTMs as molecular switches that sense context and adjust signal flow accordingly. Understanding this architecture could transform how researchers approach bone diseases, shifting attention from individual pathways to the modification events that tune them. For patients with osteoporosis or non-healing fractures, the promise is that targeting the right PTM node could restore balance to the remodeling cycle with greater precision than current therapies, which broadly suppress bone resorption or stimulate formation without addressing the underlying regulatory logic. The review does not claim to have found those targets yet, but it provides a roadmap for where to look and a framework for evaluating what is found.

Subject of Research: Post-translational modifications regulating osteoblast, osteoclast, and osteocyte signaling in bone homeostasis and disease

Article Title: Networked control of bone homeostasis: interfacing post-translational modifications with cellular signaling

Article References: Zou, Y., Kang, J., Li, Z., Niu, J., Wang, Z., Wang, S., Han, X., Ning, B., & Liu, R. (2026). Networked control of bone homeostasis: interfacing post-translational modifications with cellular signaling. BMC Medicine. https://doi.org/10.1186/s12916-026-05308-7

Image Credits: AI Generated

DOI: 10.1186/s12916-026-05308-7

Keywords: bone homeostasis, post-translational modifications, osteoblasts, osteoclasts, osteocytes, bone remodeling, osteoporosis, osteoarthritis, phosphorylation, ubiquitination, O-GlcNAcylation, cellular signaling

Long non-coding RNAs, or lncRNAs, are transcripts longer than 200 nucleotides that are not translated into proteins but instead regulate gene expression at multiple levels, including chromatin remodeling, transcription, and post-transcriptional processing. In recent years, lncRNAs have been implicated in nearly every stage of cancer progression, from uncontrolled proliferation to metastasis and resistance to chemotherapy. Yet for many of these molecules, the precise biological roles and molecular mechanisms remain poorly understood. RBMS3-AS3 was one such enigma, and the team set out to determine whether it plays a functional role in ovarian cancer pathogenesis.

The researchers began by analyzing expression data from The Cancer Genome Atlas and from human ovarian cancer samples collected with informed consent under ethics approval from China Medical University. They found that RBMS3-AS3 is highly expressed in ovarian cancer tissues compared with normal ovarian tissue, and that elevated levels of the transcript correlate with poor overall survival in patients. This clinical association immediately suggested that RBMS3-AS3 is not merely a bystander but potentially an active participant in the disease process.

To understand where the molecule operates inside the cell, the team performed subcellular localization experiments and discovered that RBMS3-AS3 is predominantly cytoplasmic in ovarian cancer cells. This location is significant because the cytoplasm is where post-transcriptional regulation occurs, including mRNA stability, splicing, and protein interactions. A cytoplasmic lncRNA is therefore positioned to interact directly with RNA-binding proteins rather than to influence transcription at the DNA level.

Using small interfering RNAs to silence RBMS3-AS3 in ovarian cancer cell lines, the researchers observed a dramatic suppression of cell proliferation, migration, and invasive capacity. Conversely, when they overexpressed the transcript, these oncogenic behaviors were enhanced. The same pattern held true for the RNA-binding proteins QKI, also known as Quaking, and RBFOX2, or RNA binding fox-1 homolog 2. Silencing either protein individually suppressed the malignant phenotype, while overexpression promoted it, indicating that both proteins function as oncoproteins in this context.

Bioinformatic analyses, including gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment, identified QKI and RBFOX2 as potential downstream targets of RBMS3-AS3. To verify this experimentally, the team performed RNA pull-down assays and RNA immunoprecipitation, or RIP, experiments. These techniques confirmed a direct physical interaction between RBMS3-AS3 and both QKI and RBFOX2 proteins inside ovarian cancer cells. The binding was not indirect or coincidental but a genuine molecular handshake between the lncRNA transcript and the two RNA-binding proteins.

The most striking mechanistic discovery came when the researchers examined what happens to QKI and RBFOX2 protein levels in the absence of RBMS3-AS3. Using cycloheximide chase experiments to block new protein synthesis, they found that silencing RBMS3-AS3 accelerated the proteasomal degradation of both QKI and RBFOX2 proteins. The mechanism involved enhanced ubiquitination, the process by which ubiquitin molecules are attached to proteins to mark them for destruction by the proteasome. In other words, RBMS3-AS3 acts as a molecular bodyguard, physically binding to QKI and RBFOX2 and preventing their ubiquitination and subsequent degradation, thereby keeping the oncoproteins stable and active inside the cancer cell.

To confirm that QKI and RBFOX2 are the functional executors of RBMS3-AS3’s oncogenic effects, the team performed co-knockdown rescue experiments. When they simultaneously silenced both QKI and RBFOX2 in cells overexpressing RBMS3-AS3, the enhanced proliferation, migration, and invasion driven by the lncRNA were abolished. This rescue experiment demonstrates that the two RNA-binding proteins are not merely associated with RBMS3-AS3 but are required for its tumor-promoting function, establishing a clear causal chain from the lncRNA through the two oncoproteins to the malignant phenotype.

The study also carried out animal experiments following guidelines from the Institutional Animal Care and Use Committee of China Medical University, providing in vivo evidence that supports the cell-based findings. Together, the clinical correlation, the cytoplasmic localization, the direct binding assays, the ubiquitination mechanism, and the rescue experiments form a coherent and technically rigorous argument that RBMS3-AS3 promotes ovarian cancer malignant progression by physically binding to and stabilizing the oncoproteins QKI and RBFOX2.

The implications for ovarian cancer therapy are significant. Ovarian cancer is often diagnosed at an advanced stage and develops resistance to platinum-based chemotherapy, leaving patients with limited options. A therapeutic strategy that targets RBMS3-AS3, either through antisense oligonucleotides or small interfering RNA delivery, could destabilize QKI and RBFOX2 simultaneously and thereby undermine multiple oncogenic pathways at once. Because the mechanism is specific to the physical interaction between the lncRNA and the two proteins, it offers a precise molecular point of intervention. The authors conclude that RBMS3-AS3 may represent a promising novel therapeutic target for ovarian cancer intervention, and their findings open a new avenue for the development of lncRNA-directed therapies against this devastating disease.

Subject of Research: LncRNA RBMS3-AS3 promotes ovarian cancer progression by regulating QKI and RBFOX2

Article Title: LncRNA RBMS3-AS3 promotes ovarian cancer progression by regulating QKI and RBFOX2

Article References: Wu, Y., Zhao, H., Du, J., Tan, B., Zhang, Z., Wei, X., Xue, R., Zhang, J., Zhang, X., Jin, X., Tang, S., & Meng, X. (2026). LncRNA RBMS3-AS3 promotes ovarian cancer progression by regulating QKI and RBFOX2. Journal of Ovarian Research. https://doi.org/10.1186/s13048-026-02303-7

Image Credits: AI Generated

DOI: 10.1186/s13048-026-02303-7

Keywords: RBMS3-AS3, lncRNA, ovarian cancer, QKI, RBFOX2, RNA-binding proteins, ubiquitination, cancer therapy, promotes, ovarian, cancer, progression

The study, published in Nature Communications, focuses on a protein called USP28, a deubiquitinating enzyme that removes ubiquitin tags from other proteins, thereby protecting them from degradation. The researchers found that USP28 is elevated in patients with sepsis and in a mouse model of the condition, and that this elevation triggers a cascade of events that ultimately kills endothelial cells through a violent form of programmed cell death known as necroptosis.

At the center of this cascade sits another protein: non-muscle myosin heavy chain IIA, or NMMHC IIA. The team demonstrated that USP28 directly removes K48-linked ubiquitin chains from NMMHC IIA at a specific amino acid position, lysine 1413, stabilizing the protein and preventing its destruction by the cellular waste-disposal system. With NMMHC IIA stabilized, it accumulates in the cell and begins promoting the trafficking of interferon-alpha/beta receptor 1 (IFNAR1) to the plasma membrane, where it becomes more active.

Once IFNAR1 reaches the cell surface, it amplifies signaling through STAT1, a transcription factor that drives inflammatory gene expression. This enhanced IFNAR1/STAT1 signaling pushes endothelial cells toward necroptosis — a form of cell death that is particularly damaging in the context of sepsis because it triggers further inflammation as cells rupture and release their contents. The researchers found that when they deleted USP28 specifically from endothelial cells in mice, or blocked it pharmacologically, sepsis-induced multi-organ injury was significantly reduced.

Crucially, the team uncovered a self-reinforcing loop: STAT1, once activated, transcriptionally increases USP28 expression, which in turn stabilizes more NMMHC IIA, which drives more IFNAR1 to the membrane, which activates more STAT1. This positive feedback loop explains how a relatively modest initial inflammatory signal can spiral into widespread vascular destruction during sepsis.

The researchers tested their hypothesis from multiple angles. When they overexpressed USP28 in endothelial cells, sepsis-induced organ damage worsened. Conversely, when they overexpressed NMMHC IIA or IFNAR1 in mice lacking endothelial USP28, the protective effect of USP28 deletion was largely abolished, confirming that these proteins act downstream of USP28 in the same pathway.

The study was conducted using a polymicrobial sepsis model in male mice, which involves puncturing the cecum to induce a bacterial infection that mimics human sepsis. The researchers also analyzed blood samples from septic patients, obtained through Zhongda Hospital at Southeast University, to confirm that USP28 elevation is relevant to human disease and not merely a rodent phenomenon.

The work was led by Jiahui Tang, Dingji Hu, and Mengchen Xu, with corresponding authors Yuanyuan Zhang, Songqiao Liu, and Junping Kou, spanning China Pharmaceutical University, Southeast University’s Zhongda Hospital, and The First People’s Hospital of Lianyungang. The research was funded by the National Natural Science Foundation of China and the Graduate Research and Innovation Projects of Jiangsu Province.

While the findings are compelling, several questions remain before this pathway can be targeted in clinical practice. The study was conducted exclusively in male mice, and sex differences in sepsis biology are well documented. Additionally, the precise pharmacological profile of USP28 inhibitors — their selectivity, toxicity, and pharmacokinetics — will need careful evaluation. Nevertheless, the identification of a specific, druggable enzymatic node in the endothelial damage cascade represents a meaningful advance in understanding how sepsis destroys blood vessels, and offers a concrete molecular target around which new therapies could eventually be designed.

The ubiquitin system, which the USP28 discovery exploits, is one of the most versatile regulatory networks in mammalian cells. Ubiquitin is a small 76-amino-acid protein that can be attached to target proteins singly or in chains of varying topology, and the shape of those chains dictates fate: K48-linked chains classically flag proteins for destruction by the proteasome, while K63-linked chains tend to scaffold signaling complexes. Deubiquitinating enzymes such as USP28 reverse this process by cleaving ubiquitin from substrates, and the human genome encodes roughly a hundred of them. Several members of this family, including USP4, USP15, and A20, have already been implicated in inflammatory and vascular disease, which lends biological plausibility to the new findings and suggests that endothelial cells rely heavily on ubiquitin editing to calibrate their response to inflammatory stress.

Necroptosis itself has emerged over the past decade as a distinctive cell death program that blends features of both regulated death and inflammatory rupture. Unlike apoptosis, which packages cellular contents into membrane-bound vesicles that are quietly consumed by phagocytes, necroptosis ends with plasma membrane rupture and the release of damage-associated molecular patterns such as HMGB1 and interleukin-33, molecules that further inflame neighboring tissue. The pathway is orchestrated by receptor-interacting protein kinases RIPK1 and RIPK3 together with the executioner protein MLKL, and it is normally held in check by caspase-8, which cleaves and disables the necroptotic machinery. When caspase-8 activity is compromised, as can occur during heavy cytokine exposure, necroptosis becomes a dominant fallback. Endothelial cells appear particularly susceptible to this form of death during systemic infection, and loss of the endothelial barrier is widely regarded as a central event in the vascular leak, coagulation disruption, and organ failure that define severe sepsis.

The involvement of NMMHC IIA in this pathway adds an intriguing dimension because this motor protein is better known for its structural roles. Non-muscle myosin IIA, encoded by the MYH9 gene, powers actin-based contractility, cell migration, and junctional integrity, and mutations in MYH9 cause a spectrum of human disorders featuring thrombocytopenia, nephropathy, and hearing loss. The finding that a cytoskeletal motor also functions as a trafficking factor for a cytokine receptor illustrates how proteins frequently moonlight in signaling roles distinct from their mechanical duties. Whether USP28-mediated stabilization of NMMHC IIA also affects its canonical cytoskeletal functions in endothelial cells, such as barrier maintenance or leukocyte transmigration, remains an open question that could broaden the physiological significance of the axis.

The IFNAR1/STAT1 arm of the pathway connects the study to a large body of work on type I interferons in sepsis. Type I interferons, best known for antiviral defense, have been shown in multiple models to worsen bacterial sepsis outcomes when excessively activated, partly through promoting inflammatory cell death and tissue damage. STAT1, the canonical downstream transcription factor, drives expression of hundreds of interferon-stimulated genes, some of which sensitize cells to necroptosis by upregulating components of the death machinery. The positive feedback loop described in the study, in which STAT1 transcriptionally upregulates USP28, fits a recurring theme in inflammatory biology in which interferon signaling amplifies its own inputs. Similar self-sustaining circuits have been described in lupus, psoriasis, and antiviral responses, and their tendency to become self-perpetuating may explain why inflammation in sepsis can continue to escalate even after the inciting pathogen has been cleared.

From a translational standpoint, the pharmacological arm of the study deserves attention. USP28 inhibitors have been under development in oncology, where the enzyme supports the stability of proteins such as c-Myc and Notch, and several small-molecule candidates have entered preclinical characterization. Repurposing such compounds for sepsis would face distinct challenges: sepsis is an acute, time-critical condition in which drugs must act rapidly, and the same ubiquitin-editing pathways that promote pathology in endothelial cells may serve protective roles elsewhere. The observation that endothelial-specific deletion of USP28 attenuated injury while global overexpression worsened it suggests that cell-type selectivity matters, and systemic inhibition could carry off-target consequences in tissues where USP28 is beneficial, including proliferating compartments of the intestine and bone marrow.

The restriction of the animal work to male mice is a notable limitation given the epidemiology of sepsis, which shows sex-dependent differences in incidence, immune response, and outcome. Estrogen-linked differences in interferon signaling are particularly well documented, and since the pathway described here converges on STAT1, a hormone-sensitive transcriptional regulator, the findings may not translate identically to female biology. Human validation, meanwhile, rests on circulating USP28 measurements from a single clinical cohort, and whether endothelial USP28 levels in patients track with disease severity, organ failure scores, or mortality will require prospective study.

Methodologically, the polymicrobial cecal ligation and puncture model used in the study is the most widely adopted experimental surrogate for human sepsis because it reproduces the mixed bacterial burden and sustained inflammation characteristic of abdominal infections, though it imperfectly captures the diversity of clinical sepsis arising from pneumonia, urinary sources, or hospital-acquired organisms. The use of endothelial-specific genetic tools, rather than global knockout, strengthens the causal interpretation by isolating the vascular compartment, and the rescue experiments, in which NMMHC IIA or IFNAR1 overexpression reversed the protection seen with USP28 loss, follow the logic of epistasis testing that is considered the gold standard for ordering genes within a pathway.

Looking forward, the most immediate questions are whether USP28 activity can be measured noninvasively in patients to identify those with active endothelial necroptosis, whether existing proteasome or interferon-signaling modulators could be repositioned to disrupt the loop, and whether the K1413 ubiquitination site on NMMHC IIA offers a more selective point of intervention than the catalytic cleft of USP28 itself. Answering these questions will determine whether the USP28–NMMHC IIA axis moves from mechanistic insight to therapeutic reality in a disease that still lacks a single approved drug targeting its core pathology.

Subject of Research: The role of the deubiquitinating enzyme USP28 in promoting endothelial necroptosis and multi-organ injury during sepsis

Article Title: USP28 potentiates endothelial necroptosis via deubiquitinating NMMHC IIA in septic male mice

Article References: Tang, J., Hu, D., Xu, M., Chen, H., Gong, S., Li, F., Yu, B., Zhang, Y., Liu, S., & Kou, J. (2026). USP28 potentiates endothelial necroptosis via deubiquitinating NMMHC IIA in septic male mice. Nature Communications. https://doi.org/10.1038/s41467-026-78666-8

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78666-8

Keywords: sepsis, USP28, endothelial dysfunction, necroptosis, NMMHC IIA, IFNAR1, STAT1, ubiquitination, Nature Communications, potentiates, endothelial, deubiquitinating