GO:0043162 ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0043162 describes the degradation of ubiquitin-tagged proteins that are sorted into multivesicular bodies (MVBs) and delivered to lysosomes or vacuoles.
• The pathway depends on ubiquitination of cargo, recognition by ESCRT machinery, and deubiquitination steps that recycle ubiquitin.
• Key yeast and mammalian regulators include Rsp5/NEDD4, Ubp2, Gga2, and MARCH11, which control sorting of transporters, receptors, and sperm proteins.
• Defects in MVB sorting are linked to cancer, neurodegeneration, and developmental disorders through altered receptor downregulation and protein quality control.
• Experimental models range from Saccharomyces cerevisiae knockout libraries to mammalian cell lines with CRISPR knockouts of ESCRT and ubiquitin-ligase genes.
• EDITGENE provides CRISPR knockout, point mutation, knock-in, overexpression, and library screening services to dissect this pathway in disease-relevant models.
Description
GO:0043162, ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway, is a biological process that targets ubiquitin-tagged proteins for degradation through the multivesicular body (MVB) route. In this pathway, cargo proteins are first modified with ubiquitin, then recognized by sorting machinery that packages them into intraluminal vesicles of MVBs, which ultimately fuse with lysosomes or vacuoles to degrade the cargo. This mechanism is essential for controlling the abundance of membrane receptors, transporters, and signaling molecules, and for maintaining protein homeostasis. Researchers study this process to understand how cells downregulate surface proteins, how defects contribute to disease, and how the pathway can be manipulated for therapeutic benefit. The pathway is highly conserved from yeast to humans, making model organisms such as Saccharomyces cerevisiae powerful tools for genetic dissection. Key molecular players include E3 ubiquitin ligases like Rsp5 and MARCH11, deubiquitinating enzymes such as Ubp2, and adaptor proteins like Gga2 that mediate sequential sorting steps.
ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway At A Glance
| GO ID | GO:0043162 |
|---|---|
| GO term | ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway |
| Ontology | biological_process |
| Synonym | ubiquitin-dependent protein breakdown via the multivesicular body pathway; ubiquitin-dependent protein catabolic process via the MVB pathway; ubiquitin-dependent protein catabolism via the MVB pathway; ubiquitin-dependent protein degradation via the multivesicular body pathway |
| Major function | Degradation of ubiquitin-tagged proteins through sorting into multivesicular bodies and delivery to lysosomes/vacuoles |
| Cellular location | Multivesicular body, endosome, lysosome/vacuole |
| Key machinery | ESCRT complexes, ubiquitin ligases, deubiquitinating enzymes, adaptor proteins |
| Conservation | Conserved from yeast to humans |
| Related processes | Endosomal sorting, receptor downregulation, protein quality control |
What Is GO:0043162?
This GO term defines the breakdown of a protein or peptide that has been covalently tagged with ubiquitin, specifically via the multivesicular body (MVB) sorting pathway. Ubiquitin-tagged proteins are sorted into MVBs and then delivered to a lysosome or vacuole for degradation. The process couples ubiquitin recognition to vesicle-mediated transport, ensuring that selected cargo is removed from the cytosol or membrane and destroyed in a degradative organelle.
Why Is ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway Important in Cell Biology?
This pathway is a central mechanism for controlling the lifetime of membrane proteins and for maintaining cellular proteostasis. It regulates the downregulation of receptors and transporters, thereby influencing signaling, nutrient uptake, and stress responses. Defects in MVB sorting contribute to cancer, neurodegeneration, and developmental disorders, making it a target for understanding disease mechanisms and for therapeutic intervention.
• Controls downregulation of cell surface receptors and transporters, affecting signaling and nutrient uptake.
• Maintains protein quality control by removing damaged or misfolded membrane proteins.
• Regulates sperm development through MARCH11-mediated sorting of SAMT family proteins.
• Involved in genotoxic stress responses, as revealed by chemogenomic profiling in yeast.
• Linked to cancer through altered degradation of oncoproteins and growth factor receptors.
• Implicated in neurodegeneration when MVB sorting is impaired, leading to toxic protein accumulation.
• Provides targets for therapeutic modulation of receptor levels in disease.
• Serves as a model for studying ubiquitin code and ESCRT biology.
• Enables functional genomics via yeast knockout libraries and CRISPR screens.
• Connects to P-body regulation through PLAA/UFD-3, linking MVB sorting to RNA metabolism.
What Happens During ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway?
Ubiquitination of Cargo Proteins
In simple terms: First, the target protein gets tagged with a ubiquitin molecule.
Cargo proteins destined for MVB sorting are modified with ubiquitin by E3 ligases such as Rsp5 in yeast or MARCH11 in mammals. This ubiquitin tag serves as a sorting signal that is recognized by downstream machinery. The type and topology of ubiquitin chains can influence sorting efficiency and fate.
Recognition and Sorting by ESCRT Machinery
In simple terms: The ubiquitin tag is recognized by a sorting machine that packages the protein into a vesicle.
ESCRT complexes (ESCRT-0, -I, -II, -III) sequentially recognize ubiquitinated cargo and concentrate it into clathrin-coated microdomains on endosomes. This leads to inward budding of the endosomal membrane, forming intraluminal vesicles (ILVs) within multivesicular bodies. The ESCRT machinery is essential for this sorting step, and its disruption causes cargo missorting.
Deubiquitination and Ubiquitin Recycling
In simple terms: Before degradation, the ubiquitin tag is often removed and recycled.
Deubiquitinating enzymes such as Ubp2 in yeast remove ubiquitin from cargo prior to ILV formation, allowing ubiquitin recycling and regulating sorting efficiency. The interplay between the E3 ligase Rsp5 and the DUB Ubp2 is required for proper transporter and receptor sorting in the MVB pathway. This step ensures that ubiquitin homeostasis is maintained.
Delivery to Lysosome/Vacuole and Degradation
In simple terms: The vesicle carrying the tagged protein fuses with the lysosome, where the protein is destroyed.
MVBs fuse with lysosomes (in mammals) or vacuoles (in yeast), delivering ILVs and their cargo to the degradative lumen. Proteases and lipases then break down the cargo proteins into amino acids and peptides. This final step completes the catabolic process defined by GO:0043162.
Sequential Ubiquitin-Independent and Ubiquitin-Dependent Steps
In simple terms: Some cargo first moves without ubiquitin, then gets tagged for the final sorting step.
For certain cargo like the yeast iron transporter ARN1, Gga2 mediates a ubiquitin-independent step from the trans-Golgi network to the endosome, followed by a ubiquitin-dependent step for MVB sorting. This illustrates that the pathway can integrate multiple sorting signals and adaptors.
Key Genes Involved in GO:0043162 ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway
The following genes and proteins are experimentally implicated in the ubiquitin-dependent MVB sorting pathway, based on the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| Rsp5 (yeast) / NEDD4 (human) | E3 ubiquitin ligase that ubiquitinates cargo for MVB sorting | Central to cargo selection; knockout affects transporter/receptor sorting |
| Ubp2 (yeast) | Deubiquitinating enzyme that removes ubiquitin from cargo | Regulates sorting efficiency and ubiquitin recycling; interacts with Rsp5 |
| Gga2 (yeast) | Adaptor protein mediating sequential sorting steps | Required for ARN1 trafficking from TGN to vacuole |
| MARCH11 (mouse) | E3 ubiquitin ligase in spermatids | Identified as ligase for SAMT family proteins; role in sperm development |
| SAMT1/2/3/4 (mouse) | Substrates of MARCH11 | Involved in spermatid development; potential markers of MVB sorting |
| ESCRT-0 (Hrs, STAM) | Recognizes ubiquitinated cargo | Essential for cargo clustering and ILV formation |
| ESCRT-I (TSG101, VPS28, VPS37) | Sorts cargo into ILVs | Knockout blocks MVB sorting and receptor downregulation |
| ESCRT-II (VPS22, VPS25, VPS36) | Mediates cargo sorting and ESCRT-III recruitment | Mutations affect MVB biogenesis |
| ESCRT-III (CHMP family) | Forms filaments that drive membrane scission | Critical for ILV formation; defects cause disease |
| VPS4 (AAA-ATPase) | Disassembles ESCRT-III | Required for recycling ESCRT components |
| PLAA/UFD-3 | Regulates P-bodies via intrinsically disordered domain | Links MVB sorting to RNA metabolism |
| ARN1 (yeast) | Iron transporter cargo | Model substrate for sequential sorting studies |
| Vps23/TSG101 | ESCRT-I component | Knockout impairs MVB sorting |
| Vps27/Hrs | ESCRT-0 component | Binds ubiquitinated cargo |
| Snf7/CHMP4 | ESCRT-III subunit | Forms filaments for membrane budding |
| Did2/CHMP1 | ESCRT-III associated | Regulates ESCRT-III dynamics |
| Vps36 | ESCRT-II subunit | Binds ubiquitin and RNA |
| Bro1/ALIX | Accessory protein | Recruits ESCRT-III and regulates sorting |
How Is ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway Regulated?
The pathway is regulated at multiple levels. E3 ligases such as Rsp5 and MARCH11 determine substrate specificity and timing of ubiquitination. Deubiquitinating enzymes like Ubp2 counterbalance ligase activity to ensure proper sorting and ubiquitin recycling. Adaptor proteins like Gga2 mediate sequential sorting steps and can integrate ubiquitin-independent and ubiquitin-dependent signals. Additionally, PLAA/UFD-3 regulates P-bodies through its intrinsically disordered domain, suggesting crosstalk between MVB sorting and RNA processing. Environmental stresses, including genotoxic chemicals, can modulate the pathway as part of cellular stress responses.
ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TSG101 | Cancer (receptor downregulation) | Knockout in cancer cell lines; xenograft models |
| CHMP2B | Neurodegeneration (frontotemporal dementia) | Knock-in of disease mutations in neurons |
| MARCH11 | Male infertility (spermatogenesis) | Knockout mouse; spermatid cultures |
| Rsp5/NEDD4 | Cancer, hypertension (ion channel regulation) | Point mutation knock-in in cell lines |
| PLAA/UFD-3 | Neurodegeneration, P-body dysregulation | Overexpression and knockout in neuronal cells |
Cancer
Defects in MVB sorting can lead to accumulation of growth factor receptors and oncoproteins at the cell surface, promoting uncontrolled proliferation. For example, impaired downregulation of receptor tyrosine kinases due to ESCRT dysfunction contributes to tumorigenesis. Targeting the pathway may restore receptor degradation and inhibit cancer growth.
Neurodegeneration
Neurons are particularly sensitive to impaired protein degradation. MVB sorting defects cause accumulation of toxic proteins and are linked to neurodegenerative diseases such as Alzheimer's and Parkinson's. ESCRT dysfunction has been observed in models of neurodegeneration, highlighting the pathway's role in neuronal proteostasis.
Developmental Disorders
Mutations in ESCRT components cause developmental disorders, including spastic paraplegia and microcephaly, due to defective receptor downregulation and membrane remodeling. MARCH11-mediated sorting is essential for spermatid development, and its disruption may cause male infertility.
Genotoxic Stress Response
Chemogenomic profiling in yeast has identified genes in the MVB pathway as important for resistance to genotoxic chemicals, suggesting a role in DNA damage response and cellular stress adaptation.
From ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate MVB sorting? | CRISPR knockout in HeLa or HEK293 cells |
| Does a disease mutation affect cargo recognition? | Point mutation knock-in of the mutation |
| Can a tag be used to track cargo trafficking? | Tagged knock-in of the cargo gene (e.g., GFP) |
| Does overexpression of a ligase enhance degradation? | Overexpression of E3 ligase in yeast or mammalian cells |
| Which genes are essential for MVB pathway? | Genome-wide CRISPR knockout library screening |
| Does a chemical inhibit MVB sorting? | Chemogenomic profiling in Saccharomyces cerevisiae knockout library |
How to Study the ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence microscopy | Cargo localization and MVB formation | Tracking receptor downregulation |
| Western blot | Cargo protein levels and ubiquitination | Assessing degradation efficiency |
| Mass spectrometry | Ubiquitin chain topology and cargo identity | Mapping ubiquitinated proteins |
| CRISPR knockout screening | Gene essentiality for MVB sorting | Identifying novel pathway components |
| Chemogenomic profiling | Chemical-genetic interactions | Drug target discovery |
| Co-immunoprecipitation | Protein-protein interactions | Validating E3-DUB complexes |
| Live-cell imaging | Real-time trafficking dynamics | Monitoring MVB fusion with lysosomes |
| Yeast knockout library | Growth phenotypes under stress | Genotoxic chemical assessment |
Genetic Screens and Chemogenomic Profiling
Genome-wide knockout libraries in Saccharomyces cerevisiae enable systematic identification of genes required for MVB sorting and resistance to genotoxic chemicals. Chemogenomic profiling can reveal chemical-genetic interactions that pinpoint pathway components.
Fluorescence Microscopy and Live-Cell Imaging
Tagging cargo proteins with fluorescent proteins allows visualization of their trafficking from the plasma membrane to MVBs and lysosomes. Co-localization with ESCRT markers confirms sorting into the MVB pathway.
Proteomics and Ubiquitin Chain Analysis
Mass spectrometry-based proteomics can identify ubiquitinated cargo and map ubiquitin chain topology. Quantitative proteomics after pathway perturbation reveals changes in protein stability.
RNA Interference and CRISPR Knockout
Knockdown or knockout of ESCRT components and ligases is used to test their requirement for cargo degradation. Rescue experiments with wild-type or mutant genes confirm specificity.
How CRISPR Can Be Used to Study GO:0043162 ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway
Knockout
CRISPR knockout of ESCRT components (e.g., TSG101, CHMP2B) or E3 ligases (e.g., Rsp5/NEDD4) abolishes MVB sorting and causes cargo accumulation. Knockout cell lines are used to test whether a gene is essential for degradation of specific substrates.
Point Mutation
Point mutation knock-in can model disease-associated missense mutations in ESCRT genes or ligases, revealing how single amino acid changes affect cargo recognition or complex assembly. Such models help dissect domain-specific functions.
Knock-in
Knock-in of tagged cargo proteins (e.g., GFP-ARN1) allows real-time tracking of MVB sorting in live cells. Knock-in of disease mutations into endogenous loci provides physiological relevance.
Overexpression
Overexpression of E3 ligases or DUBs can enhance or inhibit MVB sorting, respectively, and is used to test sufficiency. Overexpression of PLAA/UFD-3 affects P-body dynamics, linking MVB sorting to RNA metabolism.
How EDITGENE Supports ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway Research
Researchers studying ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway-related genes often need to determine whether a candidate gene is causally involved in cargo degradation, receptor downregulation, or disease progression. EDITGENE provides tailored CRISPR services to generate precisely engineered cell models for such functional studies.
Contact EDITGENE today to design your custom CRISPR model for ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway research.
Frequently Asked Questions About ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway
What is GO:0043162?
GO:0043162 is the biological process of degrading ubiquitin-tagged proteins via the multivesicular body sorting pathway, where cargo is sorted into MVBs and delivered to lysosomes or vacuoles for breakdown.
What genes are involved in ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway?
Key genes include E3 ligases like Rsp5/NEDD4 and MARCH11, DUBs like Ubp2, adaptors like Gga2, and ESCRT components such as TSG101 and CHMP2B.
How does ubiquitination target proteins to multivesicular bodies?
Ubiquitin tags on cargo are recognized by ESCRT-0 and other sorting complexes, which concentrate cargo into intraluminal vesicles of MVBs.
What is the role of ESCRT in MVB sorting?
ESCRT complexes sequentially recognize ubiquitinated cargo, drive inward budding of the endosomal membrane, and form intraluminal vesicles for degradation.
Which diseases are linked to defects in MVB sorting?
Defects are linked to cancer, neurodegeneration, developmental disorders, and male infertility due to impaired receptor downregulation and protein quality control.
How can I study MVB sorting in the lab?
Common methods include fluorescence microscopy, Western blot, proteomics, and CRISPR knockout screens in yeast or mammalian cells.
What is the role of deubiquitinating enzymes in this pathway?
DUBs like Ubp2 remove ubiquitin from cargo before ILV formation, recycling ubiquitin and regulating sorting efficiency.
Can CRISPR be used to model MVB sorting defects?
Yes, CRISPR knockout, point mutation knock-in, and tagged knock-in can model gene functions and disease mutations in the MVB pathway.
What is the connection between MVB sorting and P-bodies?
PLAA/UFD-3 regulates P-bodies through its intrinsically disordered domain, suggesting crosstalk between MVB sorting and RNA metabolism.
How does Gga2 mediate sequential sorting?
Gga2 mediates a ubiquitin-independent step from the trans-Golgi network to endosomes, followed by a ubiquitin-dependent step for MVB sorting of cargo like ARN1.
Conclusion
GO:0043162 represents a fundamental cellular process that couples ubiquitin tagging to vesicle-mediated protein degradation. Its machinery, from E3 ligases to ESCRT complexes, is highly conserved and essential for receptor downregulation, proteostasis, and development. Dysregulation of this pathway contributes to cancer, neurodegeneration, and other diseases, making it a rich area for therapeutic targeting. EDITGENE offers comprehensive CRISPR solutions to dissect this pathway and accelerate discovery.
References
- 1. Migliano SM et al.. 2018. ESCRT and Membrane Protein Ubiquitination.. Prog Mol Subcell Biol 57:107-135 PMID: 30097773
- 2. Das A et al.. 2025. PLAA/UFD-3 regulates P-bodies through its intrinsic disordered domain.. Proc Natl Acad Sci U S A 122(26):e2427250122 PMID: 40560612
- 3. Guan M et al.. 2022. Assessment of genotoxic chemicals using chemogenomic profiling based on gene-knockout library in Saccharomyces cerevisiae.. Toxicol In Vitro 79:105278 PMID: 34843885
- 4. Lam MH et al.. 2009. Interaction of the deubiquitinating enzyme Ubp2 and the e3 ligase Rsp5 is required for transporter/receptor sorting in the multivesicular body pathway.. PLoS One 4(1):e4259 PMID: 19165343
- 5. Yogo K et al.. 2012. Identification of SAMT family proteins as substrates of MARCH11 in mouse spermatids.. Histochem Cell Biol 137(1):53-65 PMID: 22075566
- 6. Deng Y et al.. 2009. Gga2 mediates sequential ubiquitin-independent and ubiquitin-dependent steps in the trafficking of ARN1 from the trans-Golgi network to the vacuole.. J Biol Chem 284(35):23830-41 PMID: 19574226
