module: dmel_clathrin_adaptor_coats
title: Clathrin and heterotetrameric adaptor protein coats in Drosophila melanogaster
label: Clathrin and AP adaptor coats
module_type: PROTEIN_COMPLEX
description: >-
  Clathrin-coated vesicles carry cargo from the plasma membrane and the
  trans-Golgi network into the endosomal system. Clathrin heavy and light
  chains assemble into three-legged triskelia that polymerize into a lattice
  over the budding membrane. Heterotetrameric adaptor protein (AP) complexes,
  each made of two large subunits, a medium (mu) and a small (sigma) subunit,
  select cargo and link the membrane to the coat. AP-2 acts in endocytosis at
  the plasma membrane, including synaptic vesicle recycling; AP-1 acts at the
  trans-Golgi network and endosomes. AP-3 sorts cargo from endosomes towards
  lysosome-related organelles; in Drosophila the AP-3 subunits are encoded by
  the classic eye-colour genes garnet (g), ruby (rb), carmine (cm) and orange
  (or), whose mutants are defective in pigment granule biogenesis.
summary: >-
  Clathrin triskelia and the AP-1, AP-2 and AP-3 adaptor complexes that select
  cargo for coated vesicles at the plasma membrane, trans-Golgi network and
  endosomes.
concepts:
  - {id: GO:0030125, label: clathrin vesicle coat}
cellular_components:
  - {id: GO:0030136, label: clathrin-coated vesicle}
notes: >-
  Boundary. The module contains clathrin and the three heterotetrameric
  adaptor complexes that FlyBase groups. AP-1 and AP-2 share a single beta
  subunit in Drosophila (AP-1-2beta), so that gene appears in both adaptor
  variants. AP-3 can also act independently of clathrin; it is kept here
  because FlyBase groups it with the other adaptor complexes. Monomeric
  adaptors, dynamin and uncoating factors are outside the module. The adaptor
  complexes carry their activity at complex level: clathrin-cargo adaptor
  activity (GO:0035615) for AP-1 and AP-2, whose subunits carry it in GOA (IBA,
  IMP, IC), and the general cargo adaptor activity (GO:0140312) for AP-3, which
  can act without clathrin and whose subunits carry cargo adaptor terms by ISS
  and IBA. Clathrin itself is a structural coat component and has no annoton
  function.
parts:
  - id: clathrin_triskelion
    label: Clathrin triskelion
    role: coat lattice
    description: Clathrin heavy and light chains that form the triskelion and polymerize into the coat lattice.
    group: CLATH
    complex_term: {id: GO:0071439, label: clathrin complex}
  - id: adaptor_complexes
    label: Heterotetrameric adaptor protein complexes
    role: cargo selection and membrane attachment
    variant_sets:
      - id: ap_complex_variants
        label: AP-1, AP-2 or AP-3 adaptor complex
        selection: ONE_OR_MORE
        variants:
          - id: ap1
            label: AP-1 adaptor complex
            description: Adaptor at the trans-Golgi network and endosomes.
            group: AP1
            complex_term: {id: GO:0030121, label: AP-1 adaptor complex}
            function: {id: GO:0035615, label: clathrin-cargo adaptor activity}
          - id: ap2
            label: AP-2 adaptor complex
            description: Adaptor for clathrin-dependent endocytosis at the plasma membrane.
            group: AP2
            complex_term: {id: GO:0030122, label: AP-2 adaptor complex}
            function: {id: GO:0035615, label: clathrin-cargo adaptor activity}
            processes:
              - {id: GO:0072583, label: clathrin-dependent endocytosis}
          - id: ap3
            label: AP-3 adaptor complex
            description: >-
              Adaptor for sorting to lysosome-related organelles; mutants in
              its subunits (garnet, ruby, carmine, orange) alter eye pigment
              granules.
            group: AP3
            complex_term: {id: GO:0030123, label: AP-3 adaptor complex}
            function: {id: GO:0140312, label: cargo adaptor activity}
            processes:
              - {id: GO:0048753, label: pigment granule organization}