GO:0031625 ubiquitin protein ligase binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031625 (ubiquitin protein ligase binding) is a molecular function describing the binding of a protein to any E3 ubiquitin-protein ligase, the enzymes that confer substrate specificity in ubiquitination.
• E3 ligases such as CRBN, UBR5, NEDD4, AIP4, RUL138, and WDR26-CTLH are representative binders or binding partners annotated to this term.
• Binding to E3 ligases is central to targeted protein degradation, including thalidomide-induced CRBN substrate recruitment and mitotic checkpoint complex disassembly by UBR5.
• Dysregulated E3-ligase binding contributes to cancer, neurodegeneration, and viral pathogenesis, making it a high-value drug target space.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential to dissect whether a candidate binder is causally involved in E3-ligase-dependent pathways.
• EDITGENE provides end-to-end CRISPR cell model generation and CRISPR library screening to accelerate functional validation of ubiquitin protein ligase binding proteins.
Description
Ubiquitin protein ligase binding (GO:0031625) is a molecular function that describes the physical interaction between a protein and an E3 ubiquitin-protein ligase. E3 ligases are the largest and most diverse class of enzymes in the ubiquitination cascade, and they determine which substrate proteins are modified with ubiquitin. Because E3 ligases often function as multi-subunit complexes, proteins that bind them can act as substrate adaptors, regulators, or inhibitors, thereby shaping ubiquitin signaling in processes ranging from protein homeostasis to cell cycle control. The biological importance of this binding function is underscored by its role in human disease and therapeutics. The CRBN-DDB1 E3 ligase complex binds thalidomide and related immunomodulatory drugs, redirecting the ligase to degrade neosubstrates such as IKZF1 and IKZF3, a mechanism now exploited in cancer therapy. UBR5 binding to mitotic checkpoint complexes controls their disassembly, linking this function to chromosome segregation fidelity. Viral proteins also exploit E3-ligase binding; the NEDD4 family ligase AIP4 interacts with Alix to enable hepatitis B virus naked capsid egress. For researchers, GO:0031625 provides a framework to annotate and interrogate proteins that directly engage E3 ligases. Functional studies using CRISPR-based knockout, point mutation, knock-in, and overexpression models are critical to determine whether a candidate binder is required for E3-ligase activity, substrate selection, or downstream cellular outcomes. This article synthesizes the QuickGO definition and verified literature to outline the mechanisms, key genes, disease links, and experimental strategies relevant to ubiquitin protein ligase binding.
ubiquitin protein ligase binding At A Glance
| GO ID | GO:0031625 |
|---|---|
| GO term | ubiquitin protein ligase binding |
| Ontology | molecular_function |
| Synonym | ubiquitin ligase binding |
| Definition | Binding to a ubiquitin protein ligase enzyme, any of the E3 proteins. |
| Major function | Mediates physical interaction with E3 ubiquitin-protein ligases to regulate substrate ubiquitination, complex assembly, or ligase activity. |
| Representative E3 ligases | CRBN, UBR5, NEDD4, AIP4, RUL138, WDR26-CTLH. |
| Related processes | Protein degradation, cell cycle checkpoint control, viral egress, nuclear protein homeostasis. |
| Disease relevance | Cancer, neurodegeneration, viral infection, developmental disorders. |
What Is GO:0031625?
In simple terms, ubiquitin protein ligase binding means a protein physically attaches to an E3 ubiquitin-protein ligase enzyme. The QuickGO definition states that this molecular function is the binding to a ubiquitin protein ligase enzyme, any of the E3 proteins. It does not describe the transfer of ubiquitin itself, but rather the interaction that positions a protein to influence E3-ligase activity, substrate recruitment, or complex assembly.
Why Is ubiquitin protein ligase binding Important in Cell Biology?
Ubiquitin protein ligase binding is important because E3 ligases are the decisive components of the ubiquitin system, and proteins that bind them can directly modulate which substrates are degraded, when, and where. This function is central to targeted protein degradation by drugs such as thalidomide and its analogs, which bind CRBN and reprogram the ligase to degrade disease-relevant proteins. It also controls fundamental processes including mitotic checkpoint silencing by UBR5 and nuclear protein quality control. Consequently, understanding GO:0031625 helps researchers identify new therapeutic targets, interpret disease mutations, and design CRISPR experiments that test causality.
• E3 ligases are the substrate-specificity factors of ubiquitination, and their binding partners often determine which proteins are modified.
• Thalidomide and related drugs bind CRBN to redirect E3-ligase activity, validating ubiquitin protein ligase binding as a druggable interface.
• UBR5 binding to mitotic checkpoint complexes regulates their disassembly, linking this function to chromosome stability.
• NEDD4 family ligases such as AIP4 interact with Alix to promote hepatitis B virus capsid egress, showing pathogen exploitation of this binding function.
• Nedd4 binding to connexin43 is phosphorylation-modulated, illustrating how signaling controls E3-ligase interactions.
• Nedd4-2 binding to DNMBP/Tuba regulates P-body localization under hyperosmotic stress, connecting this function to stress responses.
• Disordered E3 ligases use binding interactions to maintain order in nuclear protein homeostasis.
• WDR26-CTLH E3 ligase uses non-canonical substrate recognition to regulate prodrug metabolism, expanding the functional repertoire of E3 binding.
• CRISPR screens targeting E3-ligase binding interfaces can reveal new therapeutic vulnerabilities in cancer and other diseases.
• Understanding GO:0031625 supports the development of molecular glues and PROTACs that exploit E3-ligase binding.
Molecular Mechanism of ubiquitin protein ligase binding
E3 ligase recognition and binding interface
In simple terms: A protein docks onto an E3 ligase through specific surfaces, much like a key fitting a lock.
Ubiquitin protein ligase binding typically involves structured or disordered regions of the binding protein that contact the E3 ligase. For example, the CRBN-DDB1 complex binds thalidomide through a defined pocket, which then recruits neosubstrates such as IKZF1 and IKZF3. UBR5 binds mitotic checkpoint complexes to promote their disassembly, indicating that the binding interface determines the functional outcome. The human RING-H2 ligase hRUL138 contains RNA-binding domains, suggesting that its interactions may be modulated by RNA.
Substrate recruitment and ubiquitin transfer
In simple terms: Once bound, the E3 ligase can tag nearby proteins with ubiquitin, marking them for degradation or altered function.
Binding to an E3 ligase often positions a substrate for ubiquitination. In the CRBN-DDB1 complex, thalidomide binding creates a new surface that recruits neosubstrates for ubiquitination and degradation. UBR5 binding to mitotic checkpoint complexes leads to their disassembly, likely through ubiquitination of complex components. The WDR26-CTLH E3 ligase recognizes substrates in a non-canonical manner to regulate prodrug metabolism, showing diversity in substrate recruitment mechanisms.
Regulation by post-translational modifications
In simple terms: Chemical tags on the binding protein or the ligase can switch the interaction on or off.
Phosphorylation can modulate E3-ligase binding. Nedd4 binds connexin43 in a phosphorylation-modulated process, meaning that kinase signaling controls the interaction. Similarly, Nedd4-2 promotes localization of DNMBP/Tuba to P-bodies under hyperosmotic stress, a condition that may involve stress-induced modifications. These examples highlight that ubiquitin protein ligase binding is not constitutive but dynamically regulated.
Non-canonical and multi-subunit E3 ligase binding
In simple terms: Some E3 ligases are large machines, and binding proteins can interact with different subunits to change what the machine does.
The WDR26-CTLH E3 ligase is a multi-subunit complex that uses non-canonical substrate recognition to regulate prodrug metabolism. The CRBN-DDB1 complex is also multi-subunit, and thalidomide binding to CRBN alters the substrate specificity of the entire complex. Disordered E3 ligases can maintain order in nuclear protein homeostasis through dynamic binding interactions. These examples show that ubiquitin protein ligase binding can occur at various nodes within a ligase complex.
Viral and pathogen exploitation of E3-ligase binding
In simple terms: Viruses can hijack the host ubiquitin system by binding to E3 ligases.
The NEDD4 family ligase AIP4 interacts with Alix to enable hepatitis B virus naked capsid egress in an Alix ubiquitination-independent manner. This demonstrates that pathogens can exploit ubiquitin protein ligase binding for their life cycle, and that the interaction may not always lead to ubiquitination of the binding partner.
Key Genes Involved in GO:0031625 ubiquitin protein ligase binding
The following genes encode E3 ubiquitin-protein ligases or their binding partners that are directly relevant to GO:0031625, based on verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CRBN | Substrate receptor of CRBN-DDB1 E3 ligase; binds thalidomide and neosubstrates | Targeted protein degradation; drug development |
| UBR5 | HECT-domain E3 ligase; binds mitotic checkpoint complexes | Mitotic checkpoint regulation; cancer |
| RUL138 | RING-H2 ubiquitin-protein ligase with RNA-binding domains | RNA-related ubiquitination; basic mechanisms |
| AIP4 | NEDD4 family E3 ligase; interacts with Alix | Hepatitis B virus egress; viral pathogenesis |
| NEDD4 | E3 ligase; binds connexin43 in phosphorylation-modulated manner | Gap junction regulation; signaling |
| NEDD4-2 | E3 ligase; promotes DNMBP/Tuba localization to P-bodies | Hyperosmotic stress response; RNA granules |
| DNMBP/Tuba | Binding partner of NEDD4-2; scaffold protein | P-body dynamics; stress response |
| Alix | Binding partner of AIP4; involved in viral egress | HBV capsid egress; host-pathogen interaction |
| Connexin43 | Substrate of NEDD4; gap junction protein | Phosphorylation-modulated binding |
| WDR26 | Component of CTLH E3 ligase complex | Non-canonical substrate recognition; prodrug metabolism |
| CTLH complex subunits | Multi-subunit E3 ligase; binds substrates | Prodrug metabolism; cancer |
| DDB1 | Component of CRBN-DDB1 E3 ligase complex | Thalidomide response; cancer |
| IKZF1 | Neosubstrate of CRBN; transcription factor | Multiple myeloma; immunomodulatory drugs |
| IKZF3 | Neosubstrate of CRBN; transcription factor | Multiple myeloma; immunomodulatory drugs |
| UBE2 enzymes | Ubiquitin-conjugating enzymes; cooperate with E3 ligases | Ubiquitination cascade |
| Cullin proteins | Scaffold components of CRL E3 ligases | E3 ligase assembly |
| RING finger proteins | Common E3 ligase domains; mediate binding | E3 ligase classification |
How Is ubiquitin protein ligase binding Regulated?
Ubiquitin protein ligase binding is regulated at multiple levels. Post-translational modifications such as phosphorylation can modulate the interaction, as shown for Nedd4 binding to connexin43. Cellular stress, including hyperosmotic stress, can relocalize binding partners such as NEDD4-2 and DNMBP/Tuba to P-bodies. The availability of cofactors and substrate adaptors within multi-subunit E3 ligases, such as CRBN-DDB1 and WDR26-CTLH, also influences binding specificity. Additionally, disordered regions in E3 ligases may allow dynamic interactions that maintain nuclear protein homeostasis.
ubiquitin protein ligase binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CRBN | Multiple myeloma; drug response | CRBN knockout and point-mutation cell lines |
| UBR5 | Cancer; chromosomal instability | UBR5 knockout and overexpression models |
| AIP4 | Hepatitis B virus infection | AIP4 knockout hepatoma cells |
| NEDD4 | Gap junction regulation; cardiac and neurological disorders | NEDD4 knockout and phospho-mutant knock-in |
| WDR26 | Prodrug metabolism; cancer | WDR26 knockout and CTLH complex mutants |
Cancer and targeted protein degradation
The CRBN-DDB1 E3 ligase binds thalidomide and its analogs, redirecting the ligase to degrade neosubstrates such as IKZF1 and IKZF3, which is the basis for immunomodulatory drugs in multiple myeloma. UBR5 binding to mitotic checkpoint complexes controls their disassembly, and dysregulation may contribute to chromosomal instability in cancer. The WDR26-CTLH E3 ligase regulates prodrug metabolism, which could influence chemotherapy responses.
Neurodegeneration and protein homeostasis
Disordered E3 ligases maintain order in nuclear protein homeostasis, and disruption of their binding interactions may contribute to neurodegenerative diseases characterized by protein aggregation. NEDD4 family ligases are involved in trafficking and degradation of membrane proteins, and their binding to substrates like connexin43 is phosphorylation-modulated. These pathways are relevant to neuronal stress responses.
Viral pathogenesis
The NEDD4 family ligase AIP4 interacts with Alix to enable hepatitis B virus naked capsid egress in an Alix ubiquitination-independent manner. This highlights how viruses can hijack ubiquitin protein ligase binding for egress and spread, suggesting potential antiviral targets.
From ubiquitin protein ligase binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is the E3 ligase required for substrate degradation? | CRISPR knockout of the E3 ligase gene |
| Does a specific binding interface mediate the interaction? | Point-mutation knock-in of the binding interface |
| Can a disease-associated mutation alter binding? | Knock-in of the patient mutation |
| Where does the binding occur in cells? | Tagged knock-in with fluorescent or epitope tag |
| Does overexpression phenocopy the disease? | Overexpression of wild-type or mutant binder |
| Can we identify new binders? | CRISPR library screening or proteomics |
How to Study the ubiquitin protein ligase binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Affinity purification-mass spectrometry | Protein-protein interactions | Identify E3-ligase binding partners |
| Cryo-EM | Three-dimensional structure | Visualize binding interfaces |
| Ubiquitination assay | Substrate ubiquitination | Test functional consequences of binding |
| CRISPR knockout screen | Gene essentiality and drug response | Discover E3-ligase pathway components |
| Phospho-mutant knock-in | Effect of phosphorylation on binding | Study regulated interactions |
| Proximity labeling | Spatial interactome | Map binding in living cells |
| RNA-seq | Transcriptional changes | Downstream effects of E3-ligase binding |
| Immunofluorescence | Subcellular localization | Assess binding-dependent relocalization |
Proteomics and interactomics
Affinity purification coupled to mass spectrometry can identify proteins that bind E3 ligases, as demonstrated for the CRBN-DDB1 complex with thalidomide. Proximity labeling and yeast two-hybrid assays are also useful to map ubiquitin protein ligase binding networks.
Structural biology
Cryo-EM and X-ray crystallography have revealed how thalidomide binds CRBN and reshapes the substrate recognition surface. Structural studies of UBR5 and WDR26-CTLH complexes can define the binding interfaces and guide mutagenesis.
Cell-based ubiquitination assays
In vivo ubiquitination assays using tagged ubiquitin can measure whether binding to an E3 ligase leads to substrate modification. These assays are often combined with knockout or point-mutation models to establish causality.
CRISPR screening and functional genomics
Genome-wide CRISPR knockout screens can identify genes required for E3-ligase-dependent phenotypes, such as drug sensitivity. Focused libraries targeting E3 ligases and their binding partners can reveal new therapeutic targets.
How CRISPR Can Be Used to Study GO:0031625 ubiquitin protein ligase binding
Knockout
CRISPR knockout of an E3 ligase or its binding partner can abolish the interaction and reveal its cellular function. For example, CRBN knockout cells are resistant to thalidomide-induced degradation of IKZF1 and IKZF3. UBR5 knockout can impair mitotic checkpoint complex disassembly.
Point Mutation
Point mutations can disrupt specific binding interfaces without affecting overall protein stability. Mutating the thalidomide-binding pocket of CRBN prevents neosubstrate recruitment. Phospho-mutant knock-in of connexin43 can test how phosphorylation controls Nedd4 binding.
Knock-in
Knock-in of tagged or disease-associated variants allows tracking of endogenous proteins and their interactions. Tagged CRBN knock-in can be used to isolate the E3 ligase complex. Knock-in of patient mutations in UBR5 or WDR26 can model disease-associated binding defects.
Overexpression
Overexpression of wild-type or mutant E3 ligases or their binding partners can amplify phenotypes and facilitate biochemical analysis. Overexpression of hRUL138 can help study its RNA-binding and ligase activities. Overexpression of NEDD4-2 can enhance DNMBP/Tuba relocalization to P-bodies.
How EDITGENE Supports ubiquitin protein ligase binding Research
Researchers studying ubiquitin protein ligase binding-related genes often need to determine whether a candidate gene is causally involved in E3-ligase-dependent processes, such as substrate degradation, complex disassembly, or drug response. Establishing causality requires precise genetic models that can knockout, mutate, tag, or overexpress the gene of interest in relevant cell types. EDITGENE provides a comprehensive suite of CRISPR services to generate such models and to screen for novel components of ubiquitin protein ligase binding pathways.
Contact EDITGENE today to design your custom CRISPR model for ubiquitin protein ligase binding research.
Frequently Asked Questions About ubiquitin protein ligase binding
What is ubiquitin protein ligase binding?
Ubiquitin protein ligase binding (GO:0031625) is a molecular function describing the binding of a protein to an E3 ubiquitin-protein ligase enzyme, which often regulates substrate ubiquitination or ligase activity.
What genes are involved in ubiquitin protein ligase binding?
Key genes include CRBN, UBR5, RUL138, AIP4, NEDD4, NEDD4-2, WDR26, and their binding partners such as Alix, connexin43, and DNMBP/Tuba.
How does thalidomide relate to ubiquitin protein ligase binding?
Thalidomide binds the CRBN-DDB1 E3 ligase complex, altering its substrate specificity to degrade neosubstrates like IKZF1 and IKZF3, which is used in multiple myeloma therapy.
What diseases are associated with ubiquitin protein ligase binding?
Dysregulation is linked to cancer, neurodegeneration, and viral infections such as hepatitis B, through mechanisms involving CRBN, UBR5, AIP4, and NEDD4 family ligases.
How can I study ubiquitin protein ligase binding in the lab?
Common methods include affinity purification-mass spectrometry, ubiquitination assays, structural biology, and CRISPR knockout or knock-in models.
What is the role of UBR5 in mitotic checkpoint complexes?
UBR5 binds mitotic checkpoint complexes and promotes their disassembly, which is important for proper chromosome segregation.
Can viruses exploit ubiquitin protein ligase binding?
Yes, the NEDD4 family ligase AIP4 interacts with Alix to enable hepatitis B virus naked capsid egress in an Alix ubiquitination-independent manner.
Is ubiquitin protein ligase binding regulated by phosphorylation?
Yes, Nedd4 binding to connexin43 is phosphorylation-modulated, indicating that kinase signaling can control the interaction.
What CRISPR models are available for ubiquitin protein ligase binding research?
EDITGENE offers knockout, point-mutation, knock-in, overexpression, and CRISPR library screening services tailored to E3 ligases and their binding partners.
What is the difference between ubiquitin protein ligase binding and ubiquitination?
Ubiquitin protein ligase binding is the physical interaction with an E3 ligase, while ubiquitination is the covalent attachment of ubiquitin to a substrate; binding often precedes but is not identical to ubiquitination.
Conclusion
Ubiquitin protein ligase binding (GO:0031625) is a fundamental molecular function that governs the specificity of the ubiquitin system. Through interactions with E3 ligases such as CRBN, UBR5, NEDD4, and WDR26-CTLH, binding proteins control substrate degradation, cell cycle checkpoints, viral egress, and stress responses. These interactions are implicated in cancer, neurodegeneration, and infectious diseases, and they are the basis for targeted protein degradation therapeutics. To advance this field, researchers need robust genetic models to test causality. EDITGENE provides comprehensive CRISPR services, including knockout, point-mutation, knock-in, overexpression, and library screening, to help dissect the roles of ubiquitin protein ligase binding proteins in health and disease.
References
- 1. Fischer ES et al.. 2014. Structure of the DDB1-CRBN E3 ubiquitin ligase in complex with thalidomide.. Nature 512(7512):49-53 PMID: 25043012
- 2. Kaisari S et al.. 2022. Role of ubiquitin-protein ligase UBR5 in the disassembly of mitotic checkpoint complexes.. Proc Natl Acad Sci U S A 119(9) PMID: 35217622
- 3. Kreft SG et al.. 2003. hRUL138, a novel human RNA-binding RING-H2 ubiquitin-protein ligase.. J Cell Sci 116(Pt 4):605-16 PMID: 12538761
- 4. Shen S et al.. 2024. NEDD4 family ubiquitin ligase AIP4 interacts with Alix to enable HBV naked capsid egress in an Alix ubiquitination-independent manner.. PLoS Pathog 20(9):e1012485 PMID: 39259704
- 5. Leykauf K et al.. 2006. Ubiquitin protein ligase Nedd4 binds to connexin43 by a phosphorylation-modulated process.. J Cell Sci 119(Pt 17):3634-42 PMID: 16931598
- 6. Liu Z et al.. 2025. The ubiquitin ligase Nedd4-2 promotes localization of DNMBP/Tuba to P-bodies under hyperosmotic stress.. J Biol Chem 301(11):110738 PMID: 40975170
- 7. Rosenbaum JC et al.. 2011. How a disordered ubiquitin ligase maintains order in nuclear protein homeostasis.. Nucleus 2(4):264-70 PMID: 21941105
- 8. Gottemukkala KV et al.. 2024. Non-canonical substrate recognition by the human WDR26-CTLH E3 ligase regulates prodrug metabolism.. Mol Cell 84(10):1948-1963.e11 PMID: 38759627
