GO:0032399 HECT domain binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0032399 (HECT domain binding) is a molecular function defined as binding to a HECT (Homologous to the E6-AP Carboxy-Terminus) domain of a protein.
• HECT domains are catalytic modules of HECT-type E3 ubiquitin ligases, which transfer ubiquitin to substrates via a thioester intermediate.
• HECT domain binding regulates diverse processes including autophagy, mitophagy, inflammasome activation, cardiac remodeling, and viral egress [1,2,5,6,7].
• Key HECT-domain-containing proteins include E6AP/UBE3A, WWP1/2, NEDD4, SMURF1/2, HERC enzymes, and AMBRA1-associated ligases [3,5,6,7].
• Dysregulation of HECT domain interactions is implicated in cancer, neurodegeneration, inflammation, and metabolic liver disease [1,5,6,7].
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal dissection of HECT domain binding in human disease [3,5,7].
Description
GO:0032399, HECT domain binding, is a molecular function term in the Gene Ontology that describes the selective interaction of a protein with a HECT (Homologous to the E6-AP Carboxy-Terminus) domain. HECT domains are approximately 350-amino-acid catalytic modules found in a family of E3 ubiquitin ligases that form a thioester intermediate with ubiquitin before transferring it to substrate proteins. Because HECT domain binding underlies the assembly and regulation of ubiquitin signaling complexes, it is central to understanding how cells control protein stability, trafficking, and signaling. Researchers study HECT domain binding to define the specificity of ubiquitination pathways and to identify therapeutic targets in cancer, neurodegeneration, and inflammatory diseases [3,5,6,7]. The term is distinct from ubiquitin binding or HECT ligase activity; it specifically captures the recognition event between a binding partner and the HECT domain itself.
HECT domain binding At A Glance
| GO ID | GO:0032399 |
|---|---|
| GO term | HECT domain binding |
| Ontology | molecular_function |
| Synonym | None |
| Definition | Binding to a HECT, 'Homologous to the E6-AP Carboxy-Terminus', domain of a protein. |
| Major function | Mediates protein-protein interactions that regulate HECT-type E3 ubiquitin ligase assembly, substrate recognition, and catalytic activity. |
| Example binding partners | Tsg101-UEV, AMBRA1, NLRP3-associated HERC enzymes, and WWP2 substrates [2,5,6,7]. |
| Related disease areas | Cancer, neurodegeneration, inflammation, cardiac remodeling, and liver disease [1,5,6,7]. |
| Research methods | CRISPR knockout, point mutation, knock-in, overexpression, proteomics, and imaging [3,5,7]. |
What Is GO:0032399?
In simple terms, HECT domain binding is the event where a protein physically attaches to the HECT domain of another protein. The QuickGO definition states: Binding to a HECT, 'Homologous to the E6-AP Carboxy-Terminus', domain of a protein. This molecular function is typically mediated by short linear motifs or folded interaction surfaces on the binding partner that contact the HECT domain, thereby influencing ubiquitin transfer, ligase activation, or substrate recruitment.
Why Is HECT domain binding Important in Cell Biology?
HECT domain binding is important because it determines when and how HECT-type E3 ubiquitin ligases engage their substrates, thereby controlling ubiquitin-dependent processes such as autophagy, mitophagy, inflammasome activation, and viral egress [1,2,5,6]. Disruption of these interactions can lead to accumulation of toxic proteins, chronic inflammation, or impaired cellular quality control, which are hallmarks of cancer, neurodegeneration, and metabolic disease [1,5,6,7].
• Controls substrate selection by HECT-type E3 ubiquitin ligases, affecting protein half-life and localization.
• Regulates autophagy and lipid droplet turnover in liver disease.
• Modulates mitophagy and aging-related diseases through AMBRA1 interactions.
• Facilitates inflammasome activation via HERC-mediated ISGylation of NLRP3.
• Impacts cardiac remodeling through WWP2-mediated PARP1 ubiquitination.
• Influences HIV-1 egress and maturation via Tsg101-UEV interaction with HECT domains.
• Provides a mechanistic basis for targeting HECT ligases in cancer therapy.
• Serves as a node for crosstalk between ubiquitination and innate immunity.
• Offers biomarkers for neurodegenerative and inflammatory conditions [5,6].
• Enables CRISPR-based functional genomics of ubiquitin signaling [3,7].
Molecular Mechanism of HECT domain binding
Recognition of the HECT domain
In simple terms: A binding partner recognizes the HECT domain like a key fitting a lock.
HECT domain binding typically involves electrostatic and hydrophobic contacts between the binding partner and the HECT domain surface. For example, the Tsg101-UEV domain interacts with the HECT domain of a ligase to control HIV-1 egress, demonstrating that HECT domain binding can be a regulatory checkpoint in viral budding. Structural studies of HECT ligases show that the HECT domain comprises an N-terminal lobe and a C-terminal lobe that must rearrange for ubiquitin transfer, and binding partners can stabilize or disrupt this conformation.
Thioester intermediate and ubiquitin transfer
In simple terms: The HECT domain first holds ubiquitin, then hands it to a target protein.
HECT-type E3 ligases form a thioester bond between a conserved cysteine in the HECT domain and ubiquitin, then transfer ubiquitin to the substrate. HECT domain binding by adaptor proteins can position the substrate for efficient transfer or alter the processivity of ubiquitin chain formation. This mechanism distinguishes HECT ligases from RING ligases, which do not form a covalent ubiquitin intermediate.
Regulation by binding partners
In simple terms: Other proteins can turn the HECT ligase on or off by binding its HECT domain.
Binding partners can act as activators or inhibitors of HECT ligase activity. For instance, AMBRA1 interactions with HECT-type ligases regulate mitophagy, and disruption of these interactions affects mitochondrial clearance. Similarly, HERC enzymes facilitate ISGylation of NLRP3, a process that depends on HECT domain interactions and promotes inflammasome activation.
Cofactors and post-translational modifications
In simple terms: Small chemical tags on the HECT domain or its partner can change binding.
Phosphorylation, ISGylation, and ubiquitination of HECT domains or their binding partners can modulate interaction strength and specificity [3,6]. For example, ISGylation of NLRP3 by HERC enzymes requires HECT domain binding and is essential for inflammasome activation in models of inflammation. These modifications provide layers of regulation that can be targeted experimentally.
Substrate targeting and disease relevance
In simple terms: What the HECT domain binds determines which proteins get degraded.
HECT domain binding dictates substrate selection, as seen with WWP2 targeting PARP1 for degradation in cardiac remodeling. In liver disease, HECT ligase interactions influence lipid droplet turnover and autophagy, linking HECT domain binding to metabolic dysfunction. These examples illustrate how HECT domain binding directly impacts disease-relevant pathways.
Key Genes Involved in GO:0032399 HECT domain binding
The following genes and proteins are experimentally linked to HECT domain binding or HECT-type E3 ligase function.
| Gene | Major Role | Research Relevance |
|---|---|---|
| UBE3A (E6AP) | HECT-type E3 ligase; prototype of HECT domain family | Angelman syndrome, cancer, and ubiquitination research |
| WWP2 | HECT-type E3 ligase targeting PARP1 | Cardiac remodeling and cancer |
| NEDD4 | HECT-type E3 ligase regulating ion channels and receptors | Hypertension, cancer, and neurodegeneration |
| SMURF1 | HECT-type E3 ligase in TGF-beta signaling | Cancer and fibrosis |
| SMURF2 | HECT-type E3 ligase in TGF-beta and DNA damage | Cancer and genome stability |
| HERC1 | HECT-type E3 ligase with HERC domain | Neurodevelopment and inflammation |
| HERC2 | HECT-type E3 ligase in DNA repair | Cancer and neurodevelopment |
| HERC3 | HECT-type E3 ligase in ISGylation | Inflammation and innate immunity |
| HERC4 | HECT-type E3 ligase in spermatogenesis | Fertility and cancer |
| HERC5 | HECT-type E3 ligase mediating ISGylation | Antiviral immunity and inflammation |
| HERC6 | HECT-type E3 ligase in ISGylation | Innate immunity |
| AMBRA1 | Regulator of mitophagy and HECT ligase interactions | Aging-related diseases and neurodegeneration |
| Tsg101 | UEV domain protein binding HECT domains | HIV-1 egress and viral maturation |
| NLRP3 | Inflammasome sensor modified by HERC enzymes | Inflammation and autoinflammatory diseases |
| PARP1 | Substrate of WWP2 HECT ligase | Cardiac remodeling and DNA repair |
| ATG proteins | Autophagy machinery interacting with HECT ligases | Liver disease and lipid droplet turnover |
| Ferritinophagy regulators | Iron metabolism and autophagy | Organ injury and iron overload |
How Is HECT domain binding Regulated?
HECT domain binding is regulated by post-translational modifications such as phosphorylation and ISGylation, which can alter the interaction between HECT domains and their partners [3,6]. For example, ISGylation of NLRP3 by HERC enzymes depends on HECT domain binding and is required for inflammasome activation. Additionally, the availability of binding partners and the conformational state of the HECT domain can be modulated by cellular signals, including those controlling autophagy and mitophagy [1,5].
HECT domain binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| WWP2 | Cardiac remodeling and cancer | Knockout and point-mutation models in cardiomyocytes |
| AMBRA1 | Aging-related neurodegeneration | Knockout and knock-in models in neurons |
| HERC5 | Inflammation and antiviral immunity | Overexpression and knockout in macrophages |
| Tsg101 | HIV-1 egress and maturation | Point-mutation and knockout in T cells |
| UBE3A | Angelman syndrome and cancer | Knockout and knock-in in iPSCs |
HECT domain binding in cancer
HECT-type E3 ligases are frequently dysregulated in cancer, and their interactions with substrates through HECT domain binding can promote oncogenesis or tumor suppression. For instance, WWP2-mediated ubiquitination of PARP1 affects cardiac remodeling and may influence DNA repair pathways relevant to cancer. Targeting HECT domain interactions is an emerging strategy for cancer therapy.
HECT domain binding in neurodegeneration and aging
AMBRA1 interactions with HECT-type ligases regulate mitophagy, and impaired mitophagy is linked to aging-related neurodegenerative diseases. Disruption of HECT domain binding can lead to accumulation of damaged mitochondria and protein aggregates, contributing to neuronal dysfunction.
HECT domain binding in inflammation and infection
HERC enzymes facilitate ISGylation of NLRP3 through HECT domain binding, promoting inflammasome activation in models of inflammation. In viral infection, Tsg101-UEV binding to HECT domains controls HIV-1 egress, maturation, and infectivity. These findings highlight HECT domain binding as a therapeutic node in inflammatory and infectious diseases [2,6].
HECT domain binding in liver and metabolic disease
Autophagy and lipid droplet turnover are regulated by HECT ligase interactions, and their dysfunction contributes to liver disease. Ferritinophagy, a selective form of autophagy, is also linked to organ injury and may involve HECT domain binding.
From HECT domain binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of HECT domain binding affect substrate stability? | CRISPR knockout of the HECT ligase or binding partner |
| Does a specific HECT domain mutation alter ubiquitin transfer? | Point mutation of the catalytic cysteine or binding interface |
| Can a disease-associated variant disrupt HECT domain binding? | Knock-in of the patient variant in cell lines |
| Where does HECT domain binding occur in cells? | Tagged knock-in with fluorescent or affinity tags |
| Does overexpression of a binding partner drive disease phenotypes? | Overexpression models in primary cells |
| Which genes modulate HECT domain binding in a genome-wide screen? | CRISPR library screening with ubiquitination reporters |
How to Study the HECT domain binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Co-immunoprecipitation | Physical interaction between HECT domain and partner | Validation of binding in cell lysates |
| Mass spectrometry | Protein interaction partners and modifications | Discovery of HECT domain interactome |
| CRISPR knockout | Loss-of-function effects on HECT domain binding | Causal testing of candidate genes |
| CRISPR point mutation | Effect of specific residues on binding | Mapping the binding interface |
| Knock-in tagging | Localization and dynamics of HECT ligases | Live-cell imaging |
| Overexpression | Gain-of-function effects on ubiquitination | Disease modeling |
| CRISPR library screening | Genome-wide modifiers of HECT domain binding | Functional genomics |
| Proximity labeling | Transient interactions in living cells | Interactome mapping |
Proteomics and interactomics
Affinity purification coupled to mass spectrometry can identify proteins that bind HECT domains, revealing interaction networks. Proximity labeling approaches can capture transient HECT domain interactions in living cells.
Structural biology
X-ray crystallography and cryo-electron microscopy can resolve how binding partners contact the HECT domain, informing mutational studies. These methods help define the binding interface and conformational changes required for ubiquitin transfer.
Functional genomics with CRISPR
CRISPR knockout and point-mutation screens can test the requirement for HECT domain binding in cellular phenotypes such as autophagy, mitophagy, and inflammasome activation [3,5,6]. Library screening can identify modifiers of HECT domain binding.
Imaging and live-cell assays
Fluorescence microscopy of tagged HECT ligases and substrates can visualize co-localization and dynamics of HECT domain binding. Reporter assays can quantify ubiquitination and degradation in real time.
How CRISPR Can Be Used to Study GO:0032399 HECT domain binding
Knockout
CRISPR knockout of HECT ligases or their binding partners can abolish HECT domain binding and reveal downstream effects on substrate stability, autophagy, and inflammation [3,5,6]. For example, knockout of HERC enzymes impairs ISGylation of NLRP3 and inflammasome activation.
Point Mutation
Point mutations in the HECT domain or the binding interface can selectively disrupt binding without affecting protein expression, allowing precise structure-function analysis. Mutating the catalytic cysteine distinguishes binding from catalytic activity.
Knock-in
Knock-in of disease-associated variants or tags can model patient-specific effects on HECT domain binding and track protein localization in vivo. This approach is valuable for studying neurodegeneration and cancer predisposition.
Overexpression
Overexpression of HECT ligases or binding partners can amplify ubiquitination signals and model gain-of-function disease states [6,7]. It is useful for testing whether increased HECT domain binding drives pathological phenotypes.
How EDITGENE Supports HECT domain binding Research
Researchers studying HECT domain binding-related genes often need to determine whether a candidate gene is causally involved in ubiquitination, autophagy, or inflammation. EDITGENE provides CRISPR-based cell models and screening services to accelerate this discovery process.
Contact EDITGENE today to design your custom CRISPR model for HECT domain binding research.
Frequently Asked Questions About HECT domain binding
What is GO:0032399?
GO:0032399 is the Gene Ontology molecular function term for HECT domain binding, defined as binding to a HECT (Homologous to the E6-AP Carboxy-Terminus) domain of a protein.
What is HECT domain binding?
HECT domain binding is the physical interaction between a protein and the HECT domain of another protein, often regulating ubiquitin ligase activity.
What genes are involved in HECT domain binding?
Genes include UBE3A, WWP2, NEDD4, SMURF1/2, HERC family members, AMBRA1, and Tsg101 [2,3,5,6,7].
How does HECT domain binding relate to ubiquitination?
HECT domain binding positions substrates for ubiquitin transfer by HECT-type E3 ligases, which form a thioester intermediate with ubiquitin.
What diseases are linked to HECT domain binding?
Diseases include cancer, neurodegeneration, inflammatory conditions, cardiac remodeling, and liver disease [1,5,6,7].
What methods study HECT domain binding?
Methods include co-immunoprecipitation, mass spectrometry, CRISPR knockout, point mutation, knock-in, overexpression, and imaging [3,5,7].
Can CRISPR knockout help study HECT domain binding?
Yes, CRISPR knockout of HECT ligases or binding partners can reveal loss-of-function effects on ubiquitination and disease pathways [3,6].
What is the role of HECT domain binding in autophagy?
HECT domain binding regulates autophagy and mitophagy through interactions with AMBRA1 and other autophagy proteins [1,5].
How is HECT domain binding regulated?
It is regulated by post-translational modifications such as ISGylation and phosphorylation, and by conformational changes in the HECT domain [3,6].
Why is HECT domain binding important for drug discovery?
It provides a targetable interface for modulating ubiquitin signaling in cancer, inflammation, and neurodegeneration [3,6,7].
Conclusion
GO:0032399 HECT domain binding is a central molecular function that governs HECT-type E3 ubiquitin ligase interactions and downstream ubiquitination events. Its roles in autophagy, mitophagy, inflammasome activation, and viral egress make it a high-value target for understanding and treating human disease [1,2,5,6,7]. CRISPR-based models and functional genomics provide powerful tools to dissect HECT domain binding mechanisms and translate them into therapeutic strategies [3,5,7].
References
- 1. Filali-Mouncef Y et al.. 2022. The ménage à trois of autophagy, lipid droplets and liver disease.. Autophagy 18(1):50-72 PMID: 33794741
- 2. Nyenhuis DA et al.. 2023. HECT domain interaction with ubiquitin binding sites on Tsg101-UEV controls HIV-1 egress, maturation, and infectivity.. J Biol Chem 299(2):102901 PMID: 36642186
- 3. Zheng N et al.. 2017. Ubiquitin Ligases: Structure, Function, and Regulation.. Annu Rev Biochem 86:129-157 PMID: 28375744
- 4. Shao N et al.. 2026. Ferritinophagy and organ injury.. Autophagy 22(6):1171-1185 PMID: 41692973
- 5. Di Rienzo M et al.. 2024. Role of AMBRA1 in mitophagy regulation: emerging evidence in aging-related diseases.. Autophagy 20(12):2602-2615 PMID: 39113560
- 6. Qin Y et al.. 2023. Posttranslational ISGylation of NLRP3 by HERC enzymes facilitates inflammasome activation in models of inflammation.. J Clin Invest 133(20) PMID: 37651190
- 7. Zhang N et al.. 2020. Selective targeting of ubiquitination and degradation of PARP1 by E3 ubiquitin ligase WWP2 regulates isoproterenol-induced cardiac remodeling.. Cell Death Differ 27(9):2605-2619 PMID: 32139900
