module: dmel_kpc_ubiquitin_ligase
title: Kip1 ubiquitination-promoting complex in Drosophila melanogaster
label: KPC ubiquitin ligase
module_type: PROTEIN_COMPLEX
description: >-
  The Kip1 ubiquitination-promoting complex (KPC) is a heterodimeric E3
  ubiquitin ligase first described in mammals, where the RING-finger protein
  KPC1 (RNF123) ubiquitylates substrates and KPC2 (UBAC1), a
  ubiquitin-like and UBA domain protein, links ubiquitylated substrates to the
  proteasome. Mammalian KPC promotes cytoplasmic degradation of the CDK
  inhibitor p27Kip1 in G1. Drosophila Kpc1 and Kpc2 are the orthologs of
  these two subunits.
summary: >-
  Heterodimer of the RING E3 ligase Kpc1 and the proteasome-shuttle subunit
  Kpc2.
concepts:
  - {id: GO:0000151, label: ubiquitin ligase complex}
group: KPC
roles:
  Kpc1: RING E3 ligase subunit
  Kpc2: ubiquitin-like and UBA domain shuttle subunit
unit_functions:
  Kpc1: {id: GO:0061630, label: ubiquitin protein ligase activity}
notes: >-
  GO has no specific term for the KPC complex, so the module is grounded to
  the generic ubiquitin ligase complex term. The functions of KPC are known
  from mammals; Drosophila substrates have not been established. Kpc1, the
  RING-domain subunit, is given ubiquitin protein ligase activity (GO:0061630,
  which it carries in GOA by ISS and IEA); Kpc2 is a UBL-UBA adaptor with no
  known catalytic activity and has no molecular function here.
knowledge_gaps:
  - gap_statement: >-
      The substrates and biological roles of the Drosophila Kpc1-Kpc2 complex
      are not known; whether it targets the fly p27 family CDK inhibitor
      Dacapo has not been tested.
    boundary: Substrates and in vivo role of the Drosophila KPC complex.
    gap_kind: [BIOLOGY]