module: dmel_condensin_complexes
title: Condensin I and condensin II in Drosophila melanogaster
label: Condensin complexes
module_type: PROTEIN_COMPLEX
description: >-
  Condensins are SMC complexes that compact and individualize chromosomes for
  segregation. Both condensin I and condensin II are built on a heterodimer of
  SMC2 and SMC4 (Gluon in Drosophila), whose ATPase heads are bridged by a
  kleisin subunit that recruits HEAT-repeat subunits. Condensin I contains the
  kleisin Barren (CAP-H) and the HEAT subunits Cap-D2 and Cap-G. Condensin II
  contains the kleisin Cap-H2 and the HEAT subunit Cap-D3; in Drosophila
  condensin II also promotes interphase chromosome territory formation and
  antagonizes homolog pairing.
summary: >-
  SMC2-SMC4 (Gluon) condensin complexes with condensin I (Barren, Cap-D2,
  Cap-G) or condensin II (Cap-H2, Cap-D3) non-SMC subunits.
concepts:
  - {id: GO:0000796, label: condensin complex}
cellular_components:
  - {id: GO:0000785, label: chromatin}
parts:
  - id: smc2_smc4
    label: SMC2-SMC4 heterodimer
    role: SMC ATPase core
    description: SMC2 and SMC4 (glu) form the ATPase core shared by condensin I and II.
    genes: [SMC2, glu]
    unit_functions:
      SMC2: {id: GO:0016887, label: ATP hydrolysis activity}
      glu: {id: GO:0016887, label: ATP hydrolysis activity}
  - id: non_smc_subunits
    label: Kleisin and HEAT-repeat subunits
    role: condensin I or II specific subunits
    variant_sets:
      - id: condensin_variants
        label: Condensin I or condensin II non-SMC subunits
        selection: ONE_OR_MORE
        variants:
          - id: condensin_i
            label: Condensin I non-SMC subunits
            genes: [barr, Cap-D2, Cap-G]
            processes:
              - {id: GO:0007076, label: mitotic chromosome condensation}
          - id: condensin_ii
            label: Condensin II non-SMC subunits
            genes: [Cap-H2, Cap-D3]
notes: >-
  The FlyBase subgroups COND-I and COND-II share SMC2 and glu, which are
  modelled once as the core part. FlyBase lists no CAP-G2 subunit for
  condensin II. The SMC subunits are given ATP hydrolysis activity (GO:0016887), which
  they carry in GOA (ISS, NAS, IEA); their ATPase heads, engaged across the
  heterodimer, drive the complex. GO has a complex-level term for SMC-complex
  DNA entrapment (GO:0061776 ATP-dependent topological DNA co-entrapment
  activity, used by PomBase for the fission yeast complexes), but it is not
  annotated to the Drosophila proteins and is not asserted here.