module: dmel_hops_corvet_tethering
title: HOPS and CORVET tethering complexes in Drosophila melanogaster
label: HOPS and CORVET tethering
module_type: PROTEIN_COMPLEX
description: >-
  HOPS and CORVET are related hexameric tethering complexes of the endolysosomal
  system that share a class C Vps core of Vps11, Vps16, Vps18 and the
  Sec1/Munc18-family protein Vps33. HOPS adds Vps39 and Vps41, binds active
  Rab7 and promotes SNARE-dependent fusion of late endosomes, autophagosomes
  and lysosome-related organelles with lysosomes. CORVET uses Vps8 (with Vps3
  in yeast and mammals) and acts at the Rab5-positive early endosome stage.
  In Drosophila the core subunits are encoded by Vps11, Vps16A, deep orange
  (dor, Vps18) and carnation (car, Vps33A), and the HOPS-specific subunits by
  Vps39 and light (lt, Vps41); several of these were identified as eye-colour
  mutants with pigment granule defects. Drosophila also has paralogs Vps16B and
  Vps33B, which form a separate complex related to the mammalian
  VPS33B-VIPAS39 (CHEVI) complex.
summary: >-
  Class C Vps core with HOPS-specific (Vps39, Vps41) and CORVET-specific (Vps8)
  subunits that tether endosomes, autophagosomes and lysosomes for fusion.
concepts:
  - {id: GO:0030897, label: HOPS complex}
  - {id: GO:0033263, label: CORVET complex}
cellular_components:
  - {id: GO:0005770, label: late endosome}
  - {id: GO:0005764, label: lysosome}
notes: >-
  Decomposition. The class C core, the HOPS-specific pair and the
  CORVET-specific Vps8 are modelled as parts; Drosophila has no Vps3 ortholog,
  and the exact subunit composition of Drosophila CORVET-like complexes is not
  modelled beyond Vps8. Vps16B and Vps33B are included because FlyBase groups
  them with the Vps-C subunits; they are modelled as a separate part because
  they do not form HOPS. Rab7, the Mon1-Ccz1 Rab7 exchange factor and the
  lysosomal SNAREs are partners, not parts.
parts:
  - id: class_c_core
    label: Class C Vps core
    role: shared tethering core
    description: Vps11, Vps16A, Vps18 (dor) and the SM protein Vps33A (car).
    genes: [Vps11, Vps16A, dor, car]
  - id: hops_specific
    label: HOPS-specific subunits
    role: Rab7-binding HOPS subunits
    description: Vps39 and Vps41 (lt), which confer late endosome and lysosome specificity.
    genes: [Vps39, lt]
    processes:
      - {id: GO:0008333, label: endosome to lysosome transport}
  - id: corvet_specific
    label: CORVET-specific subunit Vps8
    role: early endosome CORVET subunit
    genes: [Vps8]
    complex: false
  - id: vps33b_vps16b
    label: Vps33B-Vps16B complex
    role: CHEVI-related paralog complex
    genes: [Vps33B, Vps16B]
function_note: >-
  No molecular function is assigned: the fly subunits carry no tethering
  activity term, and the ubiquitin ligase activity inferred for the
  RING-domain subunits Vps11 and Dor (ISS) is not established for the fly
  proteins.