Gamma tubulin complex component protein, N-terminal
IPR041470
Definition
This is the N-terminal domain found in components of the gamma-tubulin complex proteins (GCPs). Proteins containing this domain include spindle pole body (SBP) components such as Spc97 and Spc98 which function as the microtubule-organising centre in yeast PMID:11134079. Proteins containing this domain also include human GCP4 (Gamma-tubulin complex component 4), which has been structurally elucidated PMID:21725292. Functional studies have shown that the N-terminal domain defines the functional identity of GCPs, suggesting that all GCPs are incorporated into the helix of gamma-tubulin small complexes (gTURCs) via lateral interactions between their N-terminal domains. Thereby, they define the direct neighbours and position the GCPs within the helical wall of gTuRC PMID:27660388. Sequence alignment of human GCPs based on the GCP4 structure helped delineate conserved regions in the N- and C-terminal domains PMID:21725292. In addition to the conserved sequences, the N-terminal domains carry specific insertions of various sizes depending on the GCP, i.e. internal insertions or N-terminal extensions. These insertions may equally contribute to the function of individual GCPs as they have been implied in specific interactions with regulatory or structural proteins. For instance, GCP6 carries a large internal insertion phosphorylated by Plk4 and containing a domain of interaction with keratins, whereas the N-terminal extension of GCP3 interacts with the recruitment protein MOZART1 PMID:27660388. 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.
5 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
Loading the interactive Seroatlas explorer...