Gamma-tubulin complex component protein (IPR007259)

Short name: GCP

Overlapping homologous superfamilies


Family relationships



The microtubule organizing centres (MTOCs) of eukaryotic cells are the sites of nucleation of microtubules, and are known as the centrosome in animal cells and the spindle pole body in yeast. Gamma-tubulin, which is 30% identical to alpha and beta tubulins that form microtubules, appears to be a key protein involved in nucleation of microtubules.

Gamma tubulin can assemble into complexes of various sizes with members of the GCP family. In budding yeast, the gamma tubulin-containing small complex (gammaTuSC) contains gamma tubulin, GCP2 and GCP3 (also known as Spc97 and Spc98). In Drosophila and vertebrates, gamma tubulin forms much larger assemblies, termed gamma-tubulin ring complexes (gammaTuRCs), with gamma tubulin, GCP2, GCP3, GCP4, GCP5 and GCP6. The purified gammaTuSC and gammaTuRC complexes exhibit a 'lock washer' shape [PMID: 24075308]. However, the purified gammaTuSC has been shown to have a much lower microtubule-nucleating activity than intact gammaTuRC [PMID: 23132930]. Several models have been proposed to explain their assembly and nucleation mechanism [PMID: 21993292].

This entry represents the GCP family, whose members include GCP2/3/4/5/6 and Spc97/98 [PMID: 11950928]. They contain the GRIP1 and GRIP2 motifs, which are predicted to participate in protein-protein interactions [PMID: 11134079]. They are gamma tubulin binding proteins that have similar protein structures [PMID: 21993292].

GO terms

Biological Process

GO:0000226 microtubule cytoskeleton organization
GO:0007020 microtubule nucleation

Molecular Function

GO:0043015 gamma-tubulin binding

Cellular Component

GO:0005815 microtubule organizing center
GO:0000922 spindle pole

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.