COMMENTARY Centrosome-microtubule nucleation
نویسندگان
چکیده
In many cell types the formation of microtubules from tubulin subunits is initiated at defined nucleation sites at the centrosome. These sites contain the conserved γ-tubulin which is in association with additional not very well characterised proteins, identified as components of a γ-tubulin ring complex from Xenopus egg extracts or from suppressor screens in the yeast Saccharomyces cerevisiae. In this review we discuss two recently proposed models of how the γ-tubulin complex assists in the assembly of tubulin to form microtubules. These models propose different roles for γtubulin and the other proteins in the complex in tubulin assembly. While the structure and composition of a microtubule nucleation site is becoming clearer, it is still unknown how the cell-cycle dependent regulation of microtubule nucleation sites is achieved and whether they disassemble after microtubule formation in order to allow microtubule fluxes towards the centrosome which have been observed in mitotic cells.
منابع مشابه
The neuronal centrosome as a generator of microtubules for the axon.
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