module: dmel_gamma_tubulin_complexes
title: Gamma-tubulin complexes in Drosophila melanogaster
label: Gamma-tubulin complexes
module_type: PROTEIN_COMPLEX
description: >-
  Gamma-tubulin complexes nucleate microtubules at centrosomes, spindles and other
  microtubule-organizing centres. The basic unit is the gamma-tubulin small complex
  (gamma-TuSC), two gamma-tubulin molecules bound to Grip84 (GCP2) and Grip91
  (GCP3). In the larger gamma-tubulin ring complex (gamma-TuRC), several gamma-TuSCs
  assemble with additional GCP-family proteins (Grip75, Grip128, Grip163) and Grip71
  into a ring that templates the 13-protofilament microtubule. Drosophila has two
  gamma-tubulins: gammaTub23C, used in most tissues, and gammaTub37C, which is
  maternally supplied and acts in the female germline and early embryo. In the testis
  a separate gamma-TuRC built from testis-specific t-Grip84, t-Grip91 and t-Grip128
  paralogs acts in spermatogenesis.
summary: >-
  Gamma-tubulin small and ring complexes, including a testis-specific ring complex,
  that nucleate microtubules.
concepts:
  - {id: GO:0000930, label: gamma-tubulin complex}
parts:
  - id: gamma_tusc
    label: Gamma-tubulin small complex
    role: core nucleating unit
    description: >-
      Gamma-tubulin with Grip84 and Grip91. Either gamma-tubulin paralog
      (gammaTub23C or gammaTub37C) can occupy the gamma-tubulin positions, depending
      on tissue.
    group: G-TUSC
    complex_term: {id: GO:0008275, label: gamma-tubulin small complex}
    unit_functions:
      gammaTub23C: {id: GO:0140490, label: microtubule nucleator activity}
      gammaTub37C: {id: GO:0140490, label: microtubule nucleator activity}
    processes:
      - {id: GO:0007020, label: microtubule nucleation}
  - id: gamma_turc
    label: Gamma-tubulin ring complexes
    role: ring-shaped microtubule template
    variant_sets:
      - id: gamma_turc_variants
        label: Somatic or testis-specific gamma-TuRC
        selection: ONE_OR_MORE
        variants:
          - id: somatic_gamma_turc
            label: Gamma-tubulin ring complex
            description: >-
              Gamma-TuSC subunits plus Grip75, Grip128, Grip163 and Grip71.
            group: G-TURC
            complex_term: {id: GO:0000931, label: gamma-tubulin ring complex}
            unit_functions:
              gammaTub23C: {id: GO:0140490, label: microtubule nucleator activity}
              gammaTub37C: {id: GO:0140490, label: microtubule nucleator activity}
            processes:
              - {id: GO:0007020, label: microtubule nucleation}
          - id: testis_gamma_turc
            label: Testis-specific gamma-tubulin ring complex
            description: >-
              Ring complex of gammaTub23C with the testis-specific paralogs t-Grip84,
              t-Grip91 and t-Grip128.
            group: T-G-TURC
            complex_term: {id: GO:0000931, label: gamma-tubulin ring complex}
            unit_functions:
              gammaTub23C: {id: GO:0140490, label: microtubule nucleator activity}
              gammaTub37C: {id: GO:0140490, label: microtubule nucleator activity}
            processes:
              - {id: GO:0007020, label: microtubule nucleation}
notes: >-
  The FlyBase subgroups G-TUSC, G-TURC and T-G-TURC share subunits; the gamma-TuSC
  is modelled as the core part and the two ring complexes as variants, so shared
  subunits appear more than once. Grip71 (NEDD1 homolog) is included because FlyBase
  places it in the gamma-TuRC; in other systems its homolog acts mainly as a
  targeting factor for the ring complex. Ring attachment factors such as the augmin
  complex (dmel_augmin_complex) and centrosomal tethers are not parts. The
  gamma-tubulins are given microtubule nucleator activity (GO:0140490), which
  both paralogs carry in GOA (IBA); the Grip proteins carry gamma-tubulin and
  microtubule minus-end binding terms and are left without an annoton
  function.
group: G-TUC