Affinage

VPS8

Vacuolar protein sorting-associated protein 8 homolog · UniProt Q8N3P4

Round 2 corrected
Length
1428 aa
Mass
161.8 kDa
Annotated
2026-04-28
40 papers in source corpus 11 papers cited in narrative 11 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

VPS8 is a CORVET-complex-specific subunit that functions as an effector of Rab5-family GTPases to tether and fuse early and late endosomal membranes, thereby controlling vacuolar/lysosomal protein sorting and endosomal maturation. VPS8 binds membranes independently through its N-terminal domains and associates with the HOPS core complex through its C-terminal region; the N-terminal domains of VPS8 and its partner VPS3 are collectively required for CORVET endosomal targeting, while the core-binding region is essential for endocytic cargo turnover (PMID:19828734, PMID:20173035, PMID:23840658). Overexpression of VPS8 competitively displaces the HOPS-specific subunit VPS41, thereby blocking late endosomal maturation, autophagosome–lysosome fusion, and crinophagy, indicating that the VPS8-to-VPS41 stoichiometric ratio controls the balance between CORVET and HOPS pathway activity (PMID:31194677). In mammalian cells, VPS8 additionally localizes to Rab4/Rab11-positive recycling endosomes and is required for integrin recycling, cell adhesion, and cell migration (PMID:29476049).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 1996 Medium

    VPS8 was identified as a gene required for vacuolar hydrolase sorting, establishing its role in the biosynthetic pathway to the yeast vacuole and linking it to retrieval of the CPY receptor Vps10p from a prevacuolar compartment.

    Evidence Genetic characterization of vps8 mutants with CPY secretion and Vps10p immunofluorescence in yeast

    PMID:8864656

    Open questions at the time
    • Molecular partners of Vps8 unknown
    • No biochemical complex identified
    • Mechanism of Vps10p mislocalization not resolved
  2. 1998 Medium

    Genetic epistasis showed that VPS8 functions in pathways overlapping with PEP5/VPS11, providing the first hint that VPS8 operates within or alongside a multi-subunit tethering machinery at the vacuole.

    Evidence Double-mutant suppressor analysis of vps8-200 and pep5 in yeast

    PMID:9475722

    Open questions at the time
    • No physical interaction between Vps8 and Pep5/Vps11 demonstrated
    • Nature of the shared pathway unclear
  3. 2009 High

    Identification of Vps8 as the CORVET-specific effector subunit of Rab5/Vps21 resolved the question of how CORVET is recruited to endosomes and directly linked Vps8 to endosomal membrane tethering and clustering.

    Evidence Co-immunoprecipitation, fluorescence microscopy of endosomal clustering, epistasis with CORVET subunits in yeast

    PMID:19828734

    Open questions at the time
    • Structural basis of Vps8–Vps21 interaction unknown
    • Contribution of Vps8 versus Vps3 to membrane tethering not separated
  4. 2010 Medium

    Domain mapping revealed that Vps8 associates with membranes independently of Vps21 via its N-terminus and binds the HOPS core via its C-terminus, with the core-binding region being functionally more important for cargo sorting than the Rab-binding region.

    Evidence Deletion analysis, yeast two-hybrid, membrane fractionation, and endocytic cargo turnover assays in yeast

    PMID:20173035

    Open questions at the time
    • Membrane-binding determinant (lipid versus protein receptor) unresolved
    • Contribution of post-translational modifications not examined
  5. 2013 Medium

    Demonstration that the N-terminal β-propeller domains of both Vps3 and Vps8 are jointly required for CORVET endosomal localization clarified the modular architecture of the complex and showed that complex assembly and membrane targeting are separable events.

    Evidence Truncation mutagenesis with CORVET localization and protein sorting assays in yeast

    PMID:23840658

    Open questions at the time
    • Identity of the additional endosome-specific receptor(s) for Vps3/Vps8 N-termini unknown
    • No structural data on N-terminal domains
  6. 2014 Medium

    Extension to mammalian cells showed that CORVET is required for fusion of APPL1-positive early endosomal subpopulations and for early-to-late endosome conversion, establishing functional conservation of the CORVET tethering role in metazoans.

    Evidence siRNA depletion of CORVET subunits, in vitro endosome fusion assays, live-cell imaging in human cells

    PMID:25266290

    Open questions at the time
    • Specific contribution of VPS8 versus TGFBRAP1/VPS3 not individually assessed in this study
    • In vitro fusion reconstitution with purified CORVET not achieved
  7. 2015 Medium

    Interaction mapping of the mammalian CORVET/HOPS system showed that VPS11 acts as a molecular switch selecting between CORVET-specific (TGFBRAP1) and HOPS-specific (VPS39) subunits, explaining how a shared core assembles two distinct tethering complexes.

    Evidence Reciprocal co-immunoprecipitation and co-localization microscopy in mammalian cells

    PMID:26463206

    Open questions at the time
    • VPS8-specific interactions in mammalian CORVET not directly tested in this study
    • Structural basis of switch mechanism unknown
  8. 2016 High

    Discovery of a Drosophila 'miniCORVET' comprising Vps8, Vps16A, Dor/Vps18, and Car/Vps33A—without Vps11—revealed an unconventional four-subunit early endosomal tether and showed that CORVET and HOPS are recruited independently rather than through subunit exchange.

    Evidence Reciprocal co-immunoprecipitation, genetic null mutants, endosomal morphology in hemocytes and nephrocytes in Drosophila

    PMID:27253064

    Open questions at the time
    • No in vitro reconstitution of miniCORVET tethering activity
    • Whether a miniCORVET equivalent exists in other metazoans is untested
  9. 2018 High

    Localization of human VPS8 to Rab4/Rab11-positive recycling endosomes and demonstration that its depletion delays integrin recycling and impairs cell migration expanded the functional scope of CORVET from degradative to recycling trafficking.

    Evidence siRNA knockdown, integrin trafficking assays, cell adhesion and migration assays in human cells

    PMID:29476049

    Open questions at the time
    • Whether VPS8 acts as a tether on recycling endosomes or has a distinct mechanism is unknown
    • Relationship between CORVET and CHEVI complex on Rab11 endosomes not mechanistically resolved
  10. 2019 High

    Gain-of-function studies showed that VPS8 overexpression abolishes HOPS assembly by displacing VPS41, establishing that the VPS8/VPS41 ratio is a critical regulatory parameter controlling the balance between early and late endosomal trafficking, autophagy, and crinophagy.

    Evidence Genetic overexpression and loss-of-function in Drosophila with multiple trafficking and autophagy readouts

    PMID:31194677

    Open questions at the time
    • Whether VPS8 levels are physiologically regulated to modulate HOPS activity is unknown
    • Biochemical mechanism of competitive displacement not reconstituted in vitro
  11. 2022 Medium

    Positioning of Vps21–Vps8 upstream of PI3K/Vps34 on endosomes linked CORVET function to the PI3P–Atg21–Atg16 axis, providing the first evidence that VPS8 contributes to early autophagy initiation through endosomal PI3P generation.

    Evidence Co-immunoprecipitation and fluorescence co-localization in vps21Δ yeast with autophagy flux assays

    PMID:36076954

    Open questions at the time
    • Direct physical interaction between Vps8 and Vps34 not demonstrated
    • Functional relevance in mammalian autophagy untested
    • Single-lab observation awaiting independent replication

Open questions

Synthesis pass · forward-looking unresolved questions
  • No high-resolution structure of VPS8 (alone or within CORVET) exists, the lipid-binding specificity of its N-terminal membrane-targeting domain is uncharacterized, and whether VPS8 levels are dynamically regulated to control the CORVET/HOPS balance under physiological conditions remains unknown.
  • No structural model of VPS8
  • Membrane lipid-binding specificity undefined
  • Physiological regulation of VPS8 expression or stability not studied

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 3
Localization
GO:0005768 endosome 4 GO:0031410 cytoplasmic vesicle 1
Pathway
R-HSA-5653656 Vesicle-mediated transport 5 R-HSA-9612973 Autophagy 2
Partners
TGFBRAP1VPS11VPS16VPS18VPS21VPS3VPS33VPS41
Complex memberships
CORVETminiCORVET

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1996 VPS8 encodes a membrane-associated hydrophilic protein of 135 kDa required for accurate sorting of vacuolar hydrolases (CPY, proteinase A) in yeast. In vps8 mutants, the CPY sorting receptor Vps10p is mislocalized from the Golgi to the vacuole. VPS8 is proposed to be part of a protein complex associating with Golgi and post-Golgi membranes that functions in retrieval of Golgi membrane proteins from the prevacuolar compartment. Genetic characterization of vps8 mutants, localization of Vps10p by immunofluorescence, secretion assays for CPY and proteinase A European journal of cell biology Medium 8864656
1998 Genetic epistasis analysis shows that the vps8-200 allele partially suppresses the vestigial vacuole phenotype and hydrolase-sorting defects of pep5 (vps11) mutants, indicating that Vps8 and Pep5 function in overlapping or intersecting transport pathways to the vacuole and that three transport routes either converge or share gene products at late steps. Genetic suppressor analysis; double-mutant phenotypic analysis including vacuolar morphology and hydrolase maturation assays Genetics Medium 9475722
2009 Vps8 is a CORVET-specific subunit that interacts and cooperates with the activated Rab5 homolog Vps21 to induce clustering of late endosomal membranes in yeast, establishing Vps8 as the effector subunit of the CORVET complex. This clustering additionally requires Vps3, Vps16, and Vps33 but not other CORVET subunits, suggesting sequential assembly regulating tethering and fusion at late endosomes. In vivo monitoring of late endosome biogenesis, co-immunoprecipitation, fluorescence microscopy of endosomal clustering Molecular biology of the cell High 19828734
2010 Vps8 associates with membranes independently of the HOPS core complex and independently of the Rab GTPase Vps21. Membrane-binding regions were mapped to the N-terminal part of Vps8. Two-hybrid analysis confirmed a physical interaction between Vps8 and Vps21. Deletions abolishing HOPS core complex binding strongly impaired turnover of endocytic cargo Ste6 and vacuolar sorting of CPY, while deletions abolishing Vps21 binding had only modest effects, indicating the Vps21 interaction is not essential for endosomal trafficking. Membrane association assays, yeast two-hybrid, deletion analysis, endocytic cargo turnover assays, immunoprecipitation Eukaryotic cell Medium 20173035
2013 The N-terminal domains of Vps3 and Vps8 are required for localization of the CORVET complex to endosomes and for endocytic protein sorting. CORVET lacking both N-terminal domains mislocalizes to the cytosol and is impaired in sorting but not in complex assembly. Endosomal localization can be rescued by overexpression of Vps21 or one of the truncated subunits, indicating additional binding sites beyond the putative β-propeller domains for Vps21 and other endosome-specific factors. Truncation mutagenesis, fluorescence microscopy of CORVET localization, protein sorting assays in yeast PloS one Medium 23840658
2014 Mammalian CORVET (containing the Vps3 ortholog TGFBRAP1 as CORVET-specific subunit) is required for fusion of APPL1-positive early endosomal subpopulations and for conversion of EEA1-positive endosomes into late endosomes. CORVET-specific subunit depletion causes fragmentation of APPL1 endosomes and accumulation of enlarged EEA1 endosomes, and alters cargo transport in a cargo- and subpopulation-dependent manner. siRNA depletion of CORVET subunits, live-cell fluorescence microscopy, in vitro endosome fusion assays Traffic (Copenhagen, Denmark) Medium 25266290
2015 In mammalian cells, the CORVET complex is characterized and its subunit interactions defined. VPS11 acts as a molecular switch that binds either CORVET-specific TGFBRAP1 (ortholog of yeast Vps8 partner Vps3) or HOPS-specific VPS39/RILP, allowing selective targeting to early or late endosomes. Core interactions within CORVET and HOPS are largely conserved from yeast, but the membrane-targeting module in HOPS has changed to accommodate RILP binding. Co-immunoprecipitation, co-localization by fluorescence microscopy, interaction mapping of mammalian CORVET/HOPS subunits The Journal of biological chemistry Medium 26463206
2016 In Drosophila, Vps8 localizes to early endosomes and forms a 4-subunit 'miniCORVET' complex with Vps16A, Dor/Vps18, and Car/Vps33A, despite the absence of a clear Vps3 homolog. Loss of any miniCORVET component causes endosomal fragmentation, whereas loss of Vps11 causes endosomal enlargement similar to loss of HOPS-specific subunits. This identifies miniCORVET as an unconventional early endosomal tether. Co-immunoprecipitation, fluorescence microscopy of endosomal localization, genetic loss-of-function (null mutants), hemocyte and nephrocyte assays eLife High 27253064
2018 Human VPS3 and VPS8 (CORVET-specific subunits) localize to Rab4-positive recycling vesicles and co-localize with the CHEVI complex on Rab11-positive recycling endosomes. Depletion of VPS3 or VPS8 delays delivery of internalised integrins to recycling endosomes and their return to the plasma membrane, causing defects in integrin-dependent cell adhesion, spreading, focal adhesion formation, and cell migration, without affecting transferrin recycling. siRNA knockdown, fluorescence microscopy, integrin trafficking assays, cell adhesion and migration assays in human cells Nature communications High 29476049
2019 In Drosophila, overexpression of Vps8 inhibits HOPS-dependent trafficking routes including late endosome maturation, autophagosome-lysosome fusion, crinophagy, and lysosome-related organelle formation by abolishing late endosomal localization of HOPS-specific Vps41/Lt and preventing HOPS assembly. The proper ratio of Vps8 to Vps41 is critical because Vps8 negatively regulates HOPS by outcompeting Vps41, and miniCORVET and HOPS are recruited to target membranes independently rather than through complex transformation. Genetic overexpression and loss-of-function in Drosophila, fluorescence microscopy of endosomal/lysosomal markers, autophagy and crinophagy assays eLife High 31194677
2022 In yeast, Vps21 is required for successive co-localizations and interactions of Vps8 with Vps34 on endosomes, and of Vps34 with Atg21 on endosomes. This positions Vps21-Vps8 as upstream regulators of the PI3K-PI(3)P-Atg21-Atg16 axis at phagophores, linking endosomal CORVET function to early autophagy initiation. Co-immunoprecipitation, fluorescence co-localization microscopy in vps21Δ yeast, autophagy flux assays International journal of molecular sciences Medium 36076954

Source papers

Stage 0 corpus · 40 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2002 Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. Proceedings of the National Academy of Sciences of the United States of America 1479 12477932
2015 The BioPlex Network: A Systematic Exploration of the Human Interactome. Cell 1118 26186194
2017 Architecture of the human interactome defines protein communities and disease networks. Nature 1085 28514442
2015 A human interactome in three quantitative dimensions organized by stoichiometries and abundances. Cell 1015 26496610
2018 VIRMA mediates preferential m6A mRNA methylation in 3'UTR and near stop codon and associates with alternative polyadenylation. Cell discovery 829 29507755
2003 Complete sequencing and characterization of 21,243 full-length human cDNAs. Nature genetics 754 14702039
2021 Dual proteome-scale networks reveal cell-specific remodeling of the human interactome. Cell 705 33961781
2011 Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium. Briefings in bioinformatics 656 21873635
2004 The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome research 438 15489334
2022 OpenCell: Endogenous tagging for the cartography of human cellular organization. Science (New York, N.Y.) 432 35271311
2005 Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes. Genome research 409 16344560
2021 A proximity-dependent biotinylation map of a human cell. Nature 339 34079125
2004 Functional proteomics mapping of a human signaling pathway. Genome research 247 15231748
2018 An AP-MS- and BioID-compatible MAC-tag enables comprehensive mapping of protein interactions and subcellular localizations. Nature communications 201 29568061
2019 A protein-interaction network of interferon-stimulated genes extends the innate immune system landscape. Nature immunology 159 30833792
2010 Personalized smoking cessation: interactions between nicotine dose, dependence and quit-success genotype score. Molecular medicine (Cambridge, Mass.) 108 20379614
1998 Prediction of the coding sequences of unidentified human genes. XI. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro. DNA research : an international journal for rapid publication of reports on genes and genomes 103 9872452
2017 Mammalian APE1 controls miRNA processing and its interactome is linked to cancer RNA metabolism. Nature communications 99 28986522
2019 CORVET, CHEVI and HOPS - multisubunit tethers of the endo-lysosomal system in health and disease. Journal of cell science 96 31092635
2015 Characterization of the Mammalian CORVET and HOPS Complexes and Their Modular Restructuring for Endosome Specificity. The Journal of biological chemistry 85 26463206
2014 Mammalian CORVET is required for fusion and conversion of distinct early endosome subpopulations. Traffic (Copenhagen, Denmark) 81 25266290
2009 The CORVET subunit Vps8 cooperates with the Rab5 homolog Vps21 to induce clustering of late endosomal compartments. Molecular biology of the cell 80 19828734
2019 The midbody interactome reveals unexpected roles for PP1 phosphatases in cytokinesis. Nature communications 74 31586073
2022 Scalable multiplex co-fractionation/mass spectrometry platform for accelerated protein interactome discovery. Nature communications 65 35831314
2015 Temporal proteomics of NGF-TrkA signaling identifies an inhibitory role for the E3 ligase Cbl-b in neuroblastoma cell differentiation. Science signaling 61 25921289
2011 Combined analysis of three genome-wide association studies on vWF and FVIII plasma levels. BMC medical genetics 56 21810271
2016 MiniCORVET is a Vps8-containing early endosomal tether in Drosophila. eLife 52 27253064
2021 BioID reveals an ATG9A interaction with ATG13-ATG101 in the degradation of p62/SQSTM1-ubiquitin clusters. EMBO reports 42 34369648
2018 Vps3 and Vps8 control integrin trafficking from early to recycling endosomes and regulate integrin-dependent functions. Nature communications 41 29476049
2021 C5orf51 is a component of the MON1-CCZ1 complex and controls RAB7A localization and stability during mitophagy. Autophagy 33 34432599
2014 A genome-wide search for quantitative trait loci affecting the cortical surface area and thickness of Heschl's gyrus. Genes, brain, and behavior 33 25130324
1996 The VPS8 gene is required for localization and trafficking of the CPY sorting receptor in Saccharomyces cerevisiae. European journal of cell biology 26 8864656
2023 TRIM67 drives tumorigenesis in oligodendrogliomas through Rho GTPase-dependent membrane blebbing. Neuro-oncology 25 36215168
2019 Vps8 overexpression inhibits HOPS-dependent trafficking routes by outcompeting Vps41/Lt. eLife 24 31194677
2018 Proteomic and Biochemical Comparison of the Cellular Interaction Partners of Human VPS33A and VPS33B. Journal of molecular biology 23 29778605
2013 The N-terminal domains of Vps3 and Vps8 are critical for localization and function of the CORVET tethering complex on endosomes. PloS one 19 23840658
2010 Mapping of Vps21 and HOPS binding sites in Vps8 and effect of binding site mutants on endocytic trafficking. Eukaryotic cell 16 20173035
2022 Vps21 Directs the PI3K-PI(3)P-Atg21-Atg16 Module to Phagophores via Vps8 for Autophagy. International journal of molecular sciences 11 36076954
1998 Genetic interaction with vps8-200 allows partial suppression of the vestigial vacuole phenotype caused by a pep5 mutation in Saccharomyces cerevisiae. Genetics 11 9475722
2025 ANKK1, ANKRD50, GRK5, PACSIN1 and VPS8 are novel candidate genes associated with late onset Parkinson's disease: Definition of a novel predictive protocol based on polygenic model of inheritance. Neurobiology of disease 0 40494419