title: Monomeric gamma -tubulin nucleates microtubules.
abstract: gamma-Tubulin is required for nucleation and polarized organization of microtubules in vivo. The mechanism of microtubule nucleation by gamma-tubulin and the role of associated proteins is not understood. Here we show that in vitro translated monomeric gamma-tubulin nucleates microtubules by lowering the size of the nucleus from seven to three tubulin subunits. In capping the minus end with high affinity (10(10) m(-1)) and a binding stoichiometry of one molecule of gamma-tubulin/microtubule, gamma-tubulin establishes the critical concentration of the plus end in the medium and prevents minus end growth. gamma-Tubulin interacts strongly with beta-tubulin. A structural model accounts for these results.
authors.affiliation: Dynamique du Cytosquelette, Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, 91198 Gif-sur-Yvette, France.
authors.forename: R
authors.initials: R
authors.lastname: Leguy
authors.forename: R
authors.initials: R
authors.lastname: Melki
authors.forename: D
authors.initials: D
authors.lastname: Pantaloni
authors.forename: M F
authors.initials: MF
authors.lastname: Carlier
mesh_terms: D019281:Dimerization; D006801:Humans; D008870:Microtubules / Q000737:chemistry* / Q000378:metabolism; D014404:Tubulin / Q000737:chemistry* / Q000378:metabolism
chemical_list: D014404:Tubulin