gamma-tubulin complexes: binding to the centrosome, regulation and microtubule nucleation.
Microtubule assembly is initiated in vivo by gamma-tubulin complexes. Cytoplasmic gamma-tubulin complexes are targeted to centrosomes or to other microtubule organizing centers (MTOCs) via a set of so called gamma-tubulin complex binding proteins (GTBPs) that probably interact with the conserved Spc97p/Spc98p protein family of gamma-tubulin complexes. In other cell types, gamma-tubulin complexes may initiate microtubule formation near chromosomes in a MTOC-independent manner. Recently, major advances have been achieved through the finding that gamma-tubulin, Spc97p and Spc98p form a conserved core that is probably responsible for microtubule nucleation, and by the discovery that a yeast GTBP is regulated in a cell-cycle-dependent manner and in response to an external signal. Furthermore, it was found that the small GTPase Ran in its GDP-bound state may promote spindle assembly. In addition, an essential function of gamma-tubulin in basal body duplication has been demonstrated in Paramecium.
Schiebel
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Beatson Laboratories, The Beatson Institute for Cancer Research, Cancer Research Campaign, Glasgow, G61 1BD, UK. eschiebe@udcf.gla.ac uk.
D000818:Animals; D002502:Centrioles / Q000378:metabolism; D018385:Centrosome / Q000378:metabolism*; D006801:Humans; D008870:Microtubules / Q000378:metabolism*; D011485:Protein Binding; D008941:Spindle Apparatus / Q000378:metabolism; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*; D020931:ran GTP-Binding Protein / Q000378:metabolism
D014404:Tubulin; D020931:ran GTP-Binding Protein