GO:1902916 positive regulation of protein polyubiquitination: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1902916 describes any process that activates or increases the frequency, rate or extent of protein polyubiquitination, a key post-translational modification.
• Positive regulation of polyubiquitination is mediated by E3 ubiquitin ligases and their adaptors, and is counteracted by deubiquitinases (DUBs) [1,5,6].
• This process controls protein stability, localization, and interactions, impacting immune responses, cancer, and fibrosis [1,2,4].
• Dysregulation of polyubiquitination is linked to immune evasion, chemoresistance, and tumor progression [3,6,8].
• CRISPR screens have identified DUBs and E3 ligases that modulate polyubiquitination and drug resistance.
• Studying GO:1902916 requires integrated approaches: CRISPR KO/point mutation/knock-in, proteomics, and ubiquitination assays [1,7].
Description
Protein polyubiquitination is a post-translational modification where multiple ubiquitin molecules are attached to a substrate protein, often leading to proteasomal degradation or altered signaling. The Gene Ontology term GO:1902916, positive regulation of protein polyubiquitination, captures the processes that enhance this modification. This regulation is critical for maintaining cellular homeostasis and responding to stress, and its dysregulation is implicated in cancer, immune disorders, and fibrosis [1,5,6]. Understanding the positive regulation of polyubiquitination provides insights into how cells control protein turnover and signaling dynamics. Recent studies have highlighted the roles of E3 ligases such as KLHL6 and TRIM28 in promoting polyubiquitination of key immune regulators, thereby influencing T cell function and tumor immune evasion [1,6]. Moreover, deubiquitinases like USP18 and USP2 can positively regulate polyubiquitination of specific substrates, underscoring the complexity of this process [5,8]. Researchers studying GO:1902916 aim to identify the molecular players and mechanisms that drive polyubiquitination, with the goal of developing therapeutic strategies for related diseases.
positive regulation of protein polyubiquitination At A Glance
| GO ID | GO:1902916 |
|---|---|
| GO term | positive regulation of protein polyubiquitination |
| Ontology | biological_process |
| Synonym | activation of protein polyubiquitination; upregulation of protein polyubiquitination; positive regulation of polyubiquitin |
| Major function | Enhances the addition of ubiquitin chains to substrate proteins, affecting stability, localization, and interactions. |
| Related processes | protein ubiquitination, proteasomal degradation, immune signaling |
| Key enzymes | E3 ubiquitin ligases (e.g., TRIM28, KLHL6), deubiquitinases (e.g., USP18, USP2) |
| Disease relevance | Cancer, immune evasion, fibrosis, chemoresistance |
What Is GO:1902916?
GO:1902916, positive regulation of protein polyubiquitination, is defined as any process that activates or increases the frequency, rate or extent of protein polyubiquitination. In other words, it encompasses the molecular events that enhance the attachment of ubiquitin chains to target proteins, thereby modulating their fate and function.
Why Is positive regulation of protein polyubiquitination Important in Cell Biology?
Positive regulation of protein polyubiquitination is essential for diverse cellular processes, including immune responses, cell cycle progression, and apoptosis. Its dysregulation can lead to uncontrolled cell growth, immune escape, and resistance to therapy, making it a focal point for understanding disease mechanisms and developing targeted interventions [1,3,6,8].
• Controls protein stability and turnover, impacting cell signaling and fate [1,5].
• Regulates immune responses by modulating key signaling molecules like MAVS and PD-L1 [5,6,8].
• Involved in cancer progression and chemoresistance through ubiquitination of CDC6 and others.
• Plays a role in fibrosis via TRIM65-mediated pathways.
• Affects T cell dysfunction and antitumor immunity through KLHL6.
• Targeted by CRISPR screens to identify regulators of drug resistance.
• Provides potential biomarkers and therapeutic targets for cancer immunotherapy [2,6].
• Essential for understanding post-translational control in health and disease [1,5].
What Happens During positive regulation of protein polyubiquitination?
Recognition and Recruitment of E3 Ligases
In simple terms: E3 ligases are the enzymes that decide which proteins get tagged with ubiquitin.
The process begins with the recruitment of E3 ubiquitin ligases to specific substrates, often guided by adaptor proteins or post-translational modifications. For example, KLHL6 acts as an E3 ligase that promotes polyubiquitination of targets involved in T cell dysfunction. Similarly, TRIM28 enhances PD-L1 polyubiquitination, leading to its stabilization and immune evasion.
Ubiquitin Chain Assembly
In simple terms: Ubiquitin molecules are linked together to form a chain on the target protein.
Once recruited, E3 ligases facilitate the transfer of ubiquitin from E2 conjugating enzymes to the substrate, forming polyubiquitin chains. The type of linkage (e.g., K48 or K63) determines the functional outcome. For instance, K63-linked polyubiquitination of MAVS by USP18 positively regulates antiviral immunity.
Regulation by Deubiquitinases
In simple terms: Deubiquitinases can remove ubiquitin, but sometimes they help build chains.
Deubiquitinases (DUBs) typically reverse ubiquitination, but some, like USP18, can promote polyubiquitination of specific substrates. USP18 promotes K63-linked polyubiquitination of MAVS, enhancing innate antiviral immunity. Conversely, USP2 stabilizes PD-L1 via deubiquitination, indirectly affecting its abundance.
Substrate Fate and Signaling Outcomes
In simple terms: The ubiquitin chain acts as a signal that changes what happens to the protein.
Polyubiquitination can lead to proteasomal degradation, altered localization, or changes in protein interactions. For example, OTUD6A deubiquitinates CDC6, promoting tumor progression and chemoresistance. Thus, positive regulation of polyubiquitination directly impacts cellular decisions and disease pathways.
Key Genes Involved in GO:1902916 positive regulation of protein polyubiquitination
The following genes and proteins are key players in the positive regulation of protein polyubiquitination, as supported by recent literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KLHL6 | E3 ubiquitin ligase | Drives resistance to CD8+ T cell dysfunction |
| TIM-3 | Immune checkpoint | Palmitoylation promotes immune exhaustion |
| OTUD6A | Deubiquitinase | Deubiquitinates CDC6, promotes tumor progression |
| TRIM65 | E3 ubiquitin ligase | Deficiency alleviates renal fibrosis |
| USP18 | Deubiquitinase | Promotes K63-linked polyubiquitination of MAVS |
| TRIM28 | E3 ubiquitin ligase | Increases PD-L1 abundance, immune evasion |
| USP1 | Deubiquitinase | Regulates MAST1-driven cisplatin resistance |
| USP2 | Deubiquitinase | Stabilizes PD-L1, promotes immune evasion |
| MAVS | Mitochondrial antiviral signaling protein | K63 polyubiquitination enhances antiviral immunity |
| PD-L1 | Immune checkpoint ligand | Polyubiquitination affects stability and immune evasion [6,8] |
| CDC6 | DNA replication licensing factor | Deubiquitination by OTUD6A promotes chemoresistance |
| NUDT21 | Alternative polyadenylation factor | Mediates TRIM65 effects in fibrosis |
| MAST1 | Kinase | USP1 regulates MAST1-driven cisplatin resistance |
| CD8+ T cells | Immune cells | KLHL6 drives resistance to dysfunction |
| E2 enzymes | Ubiquitin-conjugating enzymes | Cooperate with E3 ligases in polyubiquitination [1,6] |
| Proteasome | Degradation machinery | Executes degradation of polyubiquitinated proteins |
| Ubiquitin | Small regulatory protein | Building block of polyubiquitin chains |
How Is positive regulation of protein polyubiquitination Regulated?
The positive regulation of protein polyubiquitination is itself tightly regulated at multiple levels. E3 ligases are controlled by their expression, post-translational modifications, and interactions with adaptors. Deubiquitinases can either oppose or promote polyubiquitination depending on context [5,8]. Additionally, external stimuli such as cytokines and stress signals modulate the activity of these enzymes, ensuring precise control of substrate fate [1,6].
positive regulation of protein polyubiquitination and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TRIM28 | Gastric cancer immune evasion | Knockout in gastric cancer cell lines, PD-L1 readout |
| USP2 | Tumor immune evasion | Knockout in melanoma models, PD-L1 stability assays |
| OTUD6A | Chemoresistance | Knockout in cancer cells, cisplatin sensitivity |
| TRIM65 | Renal fibrosis | Knockout mouse models, fibrosis markers |
| USP18 | Antiviral immunity | Knockout cells, MAVS polyubiquitination assays |
Cancer and Immune Evasion
Dysregulated polyubiquitination contributes to cancer progression and immune evasion. TRIM28 promotes PD-L1 abundance, allowing gastric cancer cells to escape immune surveillance. Similarly, USP2 stabilizes PD-L1, promoting tumor immune evasion. Targeting these pathways could enhance immunotherapy efficacy.
Chemoresistance
OTUD6A deubiquitinates CDC6, promoting tumor progression and chemoresistance. USP1 regulates MAST1-driven cisplatin resistance, highlighting the role of deubiquitinases in drug response. Modulating polyubiquitination may overcome resistance.
Fibrosis
TRIM65 deficiency alleviates renal fibrosis through NUDT21-mediated alternative polyadenylation, linking polyubiquitination to fibrotic processes. This suggests that E3 ligases could be therapeutic targets in fibrosis.
Antiviral Immunity
USP18 positively regulates innate antiviral immunity by promoting K63-linked polyubiquitination of MAVS. This demonstrates the importance of polyubiquitination in host defense and potential implications for viral infections.
From positive regulation of protein polyubiquitination-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X promote polyubiquitination of substrate Y? | Knockout cell line + substrate ubiquitination assay |
| Does a point mutation in E3 ligase affect substrate specificity? | Point mutation knock-in cell line |
| How does a tag affect E3 ligase localization? | Tagged knock-in (e.g., GFP) cell line |
| Does overexpression of DUB enhance polyubiquitination? | Overexpression cell line + ubiquitination assay |
| Which genes regulate drug resistance via polyubiquitination? | CRISPR library screening |
| Can we rescue phenotype by re-expressing wild-type gene? | Knock-in of wild-type or mutant cDNA |
How to Study the positive regulation of protein polyubiquitination Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ubiquitination assay | Polyubiquitin chain formation on substrate | Confirm E3 ligase activity |
| Mass spectrometry | Ubiquitination sites and chain types | Global profiling |
| CRISPR screen | Genes affecting drug resistance | Identify regulators |
| Immunoprecipitation | Protein interactions | Detect E3-substrate binding |
| Western blot | Protein stability and ubiquitination | Assess degradation |
| qPCR | Gene expression changes | Validate knockout effects |
| Flow cytometry | Surface PD-L1 levels | Immune evasion studies |
Ubiquitination Assays
In vivo and in vitro ubiquitination assays using tagged ubiquitin and immunoprecipitation can detect polyubiquitin chains on substrates. These are essential to confirm positive regulation [5,6].
Proteomics and Mass Spectrometry
Mass spectrometry-based proteomics can identify ubiquitination sites and chain linkages, providing global views of polyubiquitination changes upon genetic perturbation [1,3].
CRISPR Screening
Genome-wide CRISPR screens have identified deubiquitinases and E3 ligases that regulate drug resistance and immune evasion, linking genotype to polyubiquitination phenotypes.
Imaging and Localization
Fluorescence microscopy of tagged proteins can reveal co-localization of E3 ligases, substrates, and ubiquitin chains, offering spatial insights into regulation [2,4].
How CRISPR Can Be Used to Study GO:1902916 positive regulation of protein polyubiquitination
Knockout
CRISPR knockout of E3 ligases or DUBs can abolish polyubiquitination of specific substrates, revealing their necessity. For example, TRIM28 knockout reduces PD-L1 abundance.
Point Mutation
Introducing point mutations in catalytic residues of E3 ligases or DUBs can dissect their enzymatic activity from scaffolding functions, as shown for USP18.
Knock-in
Knock-in of tagged or mutant versions of genes allows tracking of protein localization and function, such as GFP-tagged KLHL6.
Overexpression
Overexpression of E3 ligases or DUBs can enhance polyubiquitination and drive phenotypes, like USP2-mediated PD-L1 stabilization.
How EDITGENE Supports positive regulation of protein polyubiquitination Research
Researchers studying positive regulation of protein polyubiquitination-related genes often need to determine whether a candidate gene is causally involved in the process, and CRISPR-based models are indispensable for such functional validation.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of protein polyubiquitination research.
Frequently Asked Questions About positive regulation of protein polyubiquitination
What is GO:1902916?
GO:1902916 is the Gene Ontology term for positive regulation of protein polyubiquitination, describing processes that increase the addition of ubiquitin chains to proteins.
What genes are involved in positive regulation of protein polyubiquitination?
Key genes include E3 ligases like TRIM28, KLHL6, and deubiquitinases such as USP18, USP2, and OTUD6A [1,3,5,6,8].
How does polyubiquitination affect cancer?
It can promote immune evasion by stabilizing PD-L1 or drive chemoresistance through CDC6 deubiquitination [3,6,8].
What is the role of deubiquitinases in polyubiquitination?
Some DUBs, like USP18, can promote polyubiquitination of specific substrates, while others remove ubiquitin chains [5,8].
Which diseases are linked to dysregulated polyubiquitination?
Cancer, fibrosis, and immune disorders are associated with altered polyubiquitination [1,4,6].
How can CRISPR help study polyubiquitination?
CRISPR knockout, knock-in, and point mutation models allow functional dissection of genes regulating polyubiquitination [1,7].
What methods detect polyubiquitination?
Ubiquitination assays, mass spectrometry, and immunoprecipitation are commonly used [5,6].
What is the difference between K48 and K63 polyubiquitination?
K48-linked chains typically target proteins for degradation, while K63-linked chains regulate signaling and immunity.
Can polyubiquitination be targeted therapeutically?
Yes, inhibitors of E3 ligases or DUBs are being explored for cancer and immune diseases [6,8].
What cell models are available for polyubiquitination research?
EDITGENE offers knockout, point mutation, knock-in, and overexpression cell models, plus CRISPR screening services.
Conclusion
Positive regulation of protein polyubiquitination (GO:1902916) is a fundamental process controlling protein fate and signaling, with profound implications for cancer, immunity, and fibrosis. Understanding its molecular players and mechanisms is essential for developing targeted therapies. EDITGENE provides comprehensive CRISPR solutions to accelerate this research.
References
- 1. Cheng H et al.. 2026. The ubiquitin ligase KLHL6 drives resistance to CD8(+) T cell dysfunction.. Nature 651(8105):451-461 PMID: 41535474
- 2. Zhang Z et al.. 2024. Palmitoylation of TIM-3 promotes immune exhaustion and restrains antitumor immunity.. Sci Immunol 9(101):eadp7302 PMID: 39546589
- 3. Cui J et al.. 2024. Deubiquitination of CDC6 by OTUD6A promotes tumour progression and chemoresistance.. Mol Cancer 23(1):86 PMID: 38685067
- 4. Wei S et al.. 2024. TRIM65 deficiency alleviates renal fibrosis through NUDT21-mediated alternative polyadenylation.. Cell Death Differ 31(11):1422-1438 PMID: 38951701
- 5. Hou J et al.. 2021. USP18 positively regulates innate antiviral immunity by promoting K63-linked polyubiquitination of MAVS.. Nat Commun 12(1):2970 PMID: 34016972
- 6. Ma X et al.. 2023. TRIM28 promotes the escape of gastric cancer cells from immune surveillance by increasing PD-L1 abundance.. Signal Transduct Target Ther 8(1):246 PMID: 37357254
- 7. Tyagi A et al.. 2022. CRISPR/Cas9-based genome-wide screening for deubiquitinase subfamily identifies USP1 regulating MAST1-driven cisplatin-resistance in cancer cells.. Theranostics 12(13):5949-5970 PMID: 35966591
- 8. Kuang Z et al.. 2023. USP2 promotes tumor immune evasion via deubiquitination and stabilization of PD-L1.. Cell Death Differ 30(10):2249-2264 PMID: 37670038
