GO:0000813 ESCRT I complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0000813 (ESCRT I complex) is an endosomal sorting complex required for transport that interacts with ubiquitinated cargoes.
• ESCRT-I is a heterotetrameric complex composed of VPS23/TSG101, VPS28, VPS37 and MVB12/UBAP1 subunits.
• ESCRT-I functions in multivesicular body (MVB) sorting, viral budding, membrane repair, and autophagy.
• Loss of ESCRT-I function is linked to cancer, neurodegeneration, and metabolic disorders.
• CRISPR knockout, knock-in, and tagged knock-in models are essential for studying ESCRT-I assembly and function.
• ESCRT-I interacts with ESCRT-II and ESCRT-III to mediate membrane remodeling and fission.
Description
The ESCRT I complex (GO:0000813) is a cellular component defined as an endosomal sorting complex required for transport that consists of class E vacuolar protein sorting (Vps) proteins and interacts with ubiquitinated cargoes. This complex is a key player in the endosomal sorting machinery that directs ubiquitinated transmembrane proteins into the multivesicular body (MVB) pathway, leading to their lysosomal degradation. Since its discovery, ESCRT-I has been implicated in a wide range of cellular processes beyond endosomal sorting, including viral budding, membrane repair, and autophagy. Researchers studying ESCRT-I are often interested in its role in human disease, particularly cancer and neurodegeneration, where dysregulation of ESCRT components can lead to pathological outcomes. Understanding the structure, assembly, and regulation of ESCRT-I is therefore critical for both basic cell biology and translational research.
ESCRT I complex At A Glance
| GO ID | GO:0000813 |
|---|---|
| GO term | ESCRT I complex |
| Ontology | cellular_component |
| Synonym | endosomal sorting complex required for transport |
| Major function | Endosomal sorting of ubiquitinated cargoes into multivesicular bodies |
| Subunits | VPS23/TSG101, VPS28, VPS37, MVB12/UBAP1 |
| Interactions | ESCRT-II, ESCRT-III, VPS4, ubiquitinated cargoes |
| Disease relevance | Cancer, neurodegeneration, metabolic disorders |
What Is GO:0000813?
The ESCRT I complex is a protein complex that functions in the endosomal sorting required for transport pathway. It is composed of class E Vps proteins and binds to ubiquitinated cargo proteins, facilitating their sorting into intraluminal vesicles of the multivesicular body. This complex is essential for the proper downregulation of cell surface receptors and other membrane proteins.
Why Is ESCRT I complex Important in Cell Biology?
The ESCRT I complex is fundamentally important because it serves as the entry point for cargo recognition in the ESCRT pathway, which controls the degradation of numerous membrane proteins including growth factor receptors, thereby regulating cell signaling, proliferation, and differentiation. Dysfunction of ESCRT-I leads to impaired receptor downregulation, which can contribute to oncogenesis and other diseases. Moreover, ESCRT-I is hijacked by viruses such as HIV for budding, and it plays critical roles in membrane repair and autophagy, making it a hub for host-pathogen interactions and cellular stress responses.
• Regulates downregulation of cell surface receptors, controlling signaling pathways.
• Essential for multivesicular body (MVB) biogenesis and protein sorting.
• Involved in viral budding, including HIV and Ebola virus egress.
• Participates in membrane repair and autophagy, maintaining cellular homeostasis.
• Mutations in ESCRT-I components are associated with cancer and neurodegenerative diseases.
• Serves as a model system for studying protein complex assembly and ubiquitin recognition.
• Target for antiviral and anticancer therapeutic strategies.
• Key to understanding lysosomal degradation pathways and their role in disease.
What Happens During ESCRT I complex?
Cargo Recognition and Sorting
In simple terms: ESCRT-I grabs ubiquitin-tagged proteins and sorts them into vesicles.
The ESCRT I complex recognizes ubiquitinated cargo proteins through its VPS23/TSG101 subunit, which contains a ubiquitin E2 variant (UEV) domain that binds ubiquitin. This interaction is essential for sorting cargo into the multivesicular body pathway, leading to their eventual degradation in lysosomes. The complex also interacts with other ESCRT components to ensure efficient cargo transfer.
Complex Assembly and Recruitment
In simple terms: ESCRT-I assembles with other proteins on the endosomal membrane.
ESCRT-I is recruited to endosomal membranes through interactions with phosphatidylinositol 3-phosphate and the ESCRT-II complex. The assembly of ESCRT-I is a dynamic process that involves multiple subunits, including VPS23, VPS28, VPS37, and MVB12/UBAP1. Recent studies have shown that genomic tagging of endogenous ESCRT-I preserves its membrane-remodeling functions, allowing detailed study of its assembly.
Membrane Remodeling and Fission
In simple terms: ESCRT-I helps pinch off vesicles from the membrane.
After cargo sorting, ESCRT-I coordinates with ESCRT-III and the AAA-ATPase VPS4 to mediate membrane invagination and scission, forming intraluminal vesicles. This process is critical for the formation of multivesicular bodies and the degradation of cargo. ESCRT-III function in membrane fission and repair has been extensively reviewed.
Role in Autophagy and Aggregate Clearance
In simple terms: ESCRT-I helps clear protein clumps from cells.
ESCRT-I, in conjunction with PTPN23, participates in microaggrephagy, a selective autophagy pathway for clearing MAPT/tau aggregates. This function is particularly relevant in neurodegenerative diseases where tau aggregates accumulate. Additionally, ESCRT-I is involved in lysosome repair through the LASER pathway, which couples damage sensing to ESCRT assembly.
Key Genes Involved in GO:0000813 ESCRT I complex
The following genes encode the core subunits and associated proteins of the ESCRT I complex, as well as key regulators and interaction partners.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TSG101 | Core subunit of ESCRT-I; binds ubiquitinated cargo | Frequently studied in cancer and viral budding |
| VPS28 | Core subunit; interacts with ESCRT-II | Essential for complex stability and function |
| VPS37A | Core subunit; membrane recruitment | Mutations linked to neurological disorders |
| VPS37B | Core subunit; paralog of VPS37A | Redundancy in ESCRT-I function |
| VPS37C | Core subunit; paralog of VPS37A | Tissue-specific functions |
| VPS37D | Core subunit; paralog of VPS37A | Retinal degeneration |
| MVB12A | Accessory subunit; cargo selection | Modulates ESCRT-I function |
| MVB12B | Accessory subunit; paralog of MVB12A | Neuronal development |
| UBAP1 | Accessory subunit; links to ESCRT-III | Mutations cause spastic paraplegia |
| VPS4A | AAA-ATPase; disassembles ESCRT complexes | Essential for ESCRT recycling |
| VPS4B | AAA-ATPase; paralog of VPS4A | Cancer and membrane repair |
| PTPN23 | Phosphatase; regulates ESCRT-I in autophagy | Tau aggregate clearance |
| CHMP4B | ESCRT-III subunit; membrane fission | Membrane repair and viral budding |
| IST1 | ESCRT-III associated; regulates VPS4 | Cytokinesis and membrane remodeling |
| ALIX | Accessory protein; binds ESCRT-I and ESCRT-III | Viral budding and exosome biogenesis |
| HRS | Endosomal protein; recruits ESCRT-I | Cargo sorting |
| STAM1 | Endosomal protein; interacts with HRS | Cargo sorting |
How Is ESCRT I complex Regulated?
The ESCRT I complex is regulated at multiple levels, including post-translational modifications, protein-protein interactions, and cellular stress pathways. For instance, ESCRT-I deficiency activates NFκB and JNK pathways to mediate metabolic adaptation. Additionally, the LASER pathway couples damage sensing to ESCRT assembly for lysosome repair, highlighting dynamic regulation in response to membrane damage. Phosphorylation of ESCRT-I subunits by kinases such as ULK1 may also modulate its function in autophagy.
ESCRT I complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TSG101 | Cancer, viral budding | Knockout in cancer cell lines |
| UBAP1 | Hereditary spastic paraplegia | Patient-derived iPSCs with point mutations |
| PTPN23 | Tauopathies, Alzheimer's disease | Knockout in neuronal cells |
| VPS37A | Neurological disorders | Knock-in mouse models |
| VPS4A | Membrane repair disorders | Overexpression and knockout studies |
ESCRT-I in Cancer
Dysregulation of ESCRT-I components, particularly TSG101, has been implicated in cancer progression. TSG101 is a tumor susceptibility gene, and its loss leads to impaired receptor downregulation, which can promote uncontrolled cell growth. ESCRT-I deficiency also triggers metabolic adaptation through NFκB and JNK pathways, potentially supporting cancer cell survival under stress.
ESCRT-I in Neurodegeneration
ESCRT-I plays a critical role in clearing protein aggregates such as tau, which are hallmarks of Alzheimer's disease and other tauopathies. The ESCRT-I-PTPN23-dependent microaggrephagy pathway is essential for MAPT/tau aggregate clearance, and its impairment may contribute to neurodegeneration. Mutations in ESCRT-I subunits like UBAP1 are linked to hereditary spastic paraplegia.
ESCRT-I in Membrane Repair and Lysosomal Storage Disorders
ESCRT-I is involved in lysosome repair through the LASER pathway, which senses damage and recruits ESCRT components to reseal membranes. Defects in this pathway can lead to lysosomal storage disorders and cellular stress, contributing to diseases such as Niemann-Pick disease.
From ESCRT I complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of TSG101 in receptor downregulation? | TSG101 knockout cell lines |
| How does UBAP1 mutation affect ESCRT-I assembly? | UBAP1 point mutation knock-in |
| Does ESCRT-I interact with tau aggregates? | PTPN23 knockout neurons |
| How is ESCRT-I recruited to damaged lysosomes? | Tagged knock-in of VPS28 |
| Can ESCRT-I overexpression rescue membrane repair? | Overexpression of VPS37A |
| What is the effect of ESCRT-I deficiency on metabolism? | ESCRT-I knockout in metabolic tissues |
How to Study the ESCRT I complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Genomic tagging (CRISPR knock-in) | Endogenous protein localization and dynamics | Live-cell imaging of ESCRT-I |
| AP-MS | Protein-protein interactions | Identifying ESCRT-I partners |
| Flow cytometry | Cargo degradation | EGFR downregulation |
| Fluorescence microscopy | Cargo sorting and MVB formation | Localization studies |
| Autophagy flux assays | Aggregate clearance | Tau clearance |
| Lysosome repair assay | Membrane resealing | LASER pathway |
| RNA-seq | Transcriptional changes | ESCRT-I deficiency |
| CRISPR library screening | Gene essentiality and synthetic lethality | Identifying ESCRT-I vulnerabilities |
Genomic Tagging and Live-Cell Imaging
Genomic tagging of endogenous ESCRT-I subunits, such as VPS28 or TSG101, with fluorescent proteins allows real-time visualization of complex assembly and dynamics at endosomes. This approach preserves physiological expression levels and has been shown to maintain ESCRT-mediated membrane-remodeling functions.
Proteomics and Interactomics
Affinity purification coupled with mass spectrometry (AP-MS) can identify novel ESCRT-I interaction partners and post-translational modifications. Proximity labeling techniques like BioID can map the ESCRT-I interactome in living cells.
Functional Assays for Cargo Sorting
Flow cytometry and fluorescent microscopy using cargo proteins like EGFR can assess ESCRT-I-dependent sorting and degradation. RNA interference or CRISPR knockout of ESCRT-I subunits followed by cargo trafficking assays is a standard method.
Autophagy and Aggregate Clearance Assays
To study ESCRT-I in microaggrephagy, cells expressing fluorescently tagged tau aggregates can be monitored for clearance in the presence or absence of ESCRT-I components. Lysosome repair assays using membrane-damaging agents and LASER pathway readouts are also employed.
How CRISPR Can Be Used to Study GO:0000813 ESCRT I complex
Knockout
CRISPR knockout of ESCRT-I subunits such as TSG101 or VPS28 is widely used to study loss-of-function phenotypes, including impaired receptor degradation and MVB formation. Knockout cell lines are valuable for identifying compensatory pathways and drug sensitivities.
Point Mutation
Introducing point mutations in ESCRT-I genes, such as in the ubiquitin-binding domain of TSG101, allows precise dissection of cargo recognition and complex assembly. Point mutation knock-in models can mimic patient-specific mutations found in diseases like spastic paraplegia.
Knock-in
Knock-in of tagged ESCRT-I subunits (e.g., GFP-VPS28) enables visualization of endogenous complexes and their dynamics. This approach is crucial for understanding real-time assembly and disassembly at endosomes.
Overexpression
Overexpression of wild-type or mutant ESCRT-I components can rescue knockout phenotypes or induce dominant-negative effects, helping to establish causality. Overexpression models are also used to study viral budding and membrane repair.
How EDITGENE Supports ESCRT I complex Research
Researchers studying ESCRT I complex-related genes often need to determine whether a candidate gene is causally involved in endosomal sorting, membrane repair, or disease pathogenesis. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research, from gene knockout to precise point mutations and tagged knock-ins.
Contact EDITGENE today to design your custom CRISPR model for ESCRT I complex research.
Frequently Asked Questions About ESCRT I complex
What is the ESCRT I complex?
The ESCRT I complex (GO:0000813) is a protein complex that sorts ubiquitinated cargoes into multivesicular bodies for degradation.
What genes are involved in the ESCRT I complex?
Core genes include TSG101, VPS28, VPS37A-D, MVB12A/B, and UBAP1.
What is the function of ESCRT-I in cells?
It mediates endosomal sorting, viral budding, membrane repair, and autophagy.
How is ESCRT-I related to cancer?
TSG101 is a tumor susceptibility gene, and ESCRT-I dysfunction impairs receptor downregulation, promoting oncogenesis.
What diseases are associated with ESCRT-I mutations?
Mutations in UBAP1 cause spastic paraplegia, and ESCRT-I dysfunction is linked to neurodegeneration and metabolic disorders.
How can I study ESCRT-I using CRISPR?
CRISPR knockout, knock-in, and tagged knock-in models allow functional dissection of ESCRT-I subunits.
What is the role of ESCRT-I in autophagy?
ESCRT-I, with PTPN23, mediates microaggrephagy for clearing tau aggregates.
How does ESCRT-I participate in membrane repair?
The LASER pathway couples damage sensing to ESCRT-I assembly for lysosome repair.
What are the subunits of ESCRT-I?
ESCRT-I is a heterotetramer of VPS23/TSG101, VPS28, VPS37, and MVB12/UBAP1.
Why is ESCRT-I important for viral budding?
Many enveloped viruses, including HIV, hijack ESCRT-I to facilitate their release from cells.
Conclusion
The ESCRT I complex (GO:0000813) is a central component of the endosomal sorting machinery with critical roles in protein degradation, membrane remodeling, and cellular stress responses. Its dysfunction is linked to cancer, neurodegeneration, and metabolic diseases, making it a prime target for both basic and translational research. Advances in CRISPR-based models and imaging technologies continue to unravel the molecular details of ESCRT-I assembly and function, offering new opportunities for therapeutic intervention.
References
- 1. Henne WM et al.. 2011. The ESCRT pathway.. Dev Cell 21(1):77-91 PMID: 21763610
- 2. Burigotto M et al.. 2026. ESCRT-III function in membrane fission and repair.. Nat Rev Mol Cell Biol 27(4):297-315 PMID: 41299081
- 4. Hoffman HK et al.. 2019. Genomic tagging of endogenous human ESCRT-I complex preserves ESCRT-mediated membrane-remodeling functions.. J Biol Chem 294(44):16266-16281 PMID: 31519756
- 5. Chu T et al.. 2006. New component of ESCRT-I regulates endosomal sorting complex assembly.. J Cell Biol 175(5):815-23 PMID: 17145965
- 6. Cendrowski J et al.. 2024. NFκB and JNK pathways mediate metabolic adaptation upon ESCRT-I deficiency.. Cell Mol Life Sci 81(1):458 PMID: 39560723
- 7. Hirayama S et al.. 2025. Microaggrephagy: an ESCRT-I-PTPN23-dependent pathway for MAPT/tau aggregate clearance.. Autophagy 21(11):2521-2522 PMID: 40574287
- 8. Goul CS et al.. 2026. LASER couples damage sensing to ESCRT assembly for lysosome repair.. Nature 656(8126):216-226 PMID: 42236937
