title: The where, when and how of microtubule nucleation - one ring to rule them all.
abstract: The function of microtubules depends on their arrangement into highly ordered arrays. Spatio-temporal control over the formation of new microtubules and regulation of their properties are central to the organization of these arrays. The nucleation of new microtubules requires γ-tubulin, an essential protein that assembles into multi-subunit complexes and is found in all eukaryotic organisms. However, the way in which γ-tubulin complexes are regulated and how this affects nucleation and, potentially, microtubule behavior, is poorly understood. γ-tubulin has been found in complexes of various sizes but several lines of evidence suggest that only large, ring-shaped complexes function as efficient microtubule nucleators. Human γ-tubulin ring complexes (γTuRCs) are composed of γ-tubulin and the γ-tubulin complex components (GCPs) 2, 3, 4, 5 and 6, which are members of a conserved protein family. Recent work has identified additional unrelated γTuRC subunits, as well as a large number of more transient γTuRC interactors. In this Commentary, we discuss the regulation of γTuRC-dependent microtubule nucleation as a key mechanism of microtubule organization. Specifically, we focus on the regulatory roles of the γTuRC subunits and interactors and present an overview of other mechanisms that regulate γTuRC-dependent microtubule nucleation and organization.
authors.affiliation: Cell and Developmental Biology Programme, 08028 Barcelona,  Spain.
authors.forename: Neus
authors.initials: N
authors.lastname: Teixidó-Travesa
authors.forename: Joan
authors.initials: J
authors.lastname: Roig
authors.forename: Jens
authors.initials: J
authors.lastname: Lüders
mesh_terms: D000818:Animals; D006801:Humans; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014404:Tubulin