An extended γ-tubulin ring functions as a stable platform in microtubule nucleation

• Verfasst von: Erlemann, Sarah [VerfasserIn]
• Verfasst von: Neuner, Annett [VerfasserIn]
• Verfasst von: Gombos, Linda [VerfasserIn]
• Verfasst von: Schiebel, Elmar [VerfasserIn]
• Titel: An extended γ-tubulin ring functions as a stable platform in microtubule nucleation
• Verf.angabe: Sarah Erlemann, Annett Neuner, Linda Gombos, Romain Gibeaux, Claude Antony, and Elmar Schiebel
• E-Jahr: 2012
• Jahr: 2 April, 2012
• Umfang: 16 S.
• Fussnoten: Gesehen am 22.11.2018
• Titel Quelle: Enthalten in: The journal of cell biology
• Ort Quelle: New York, NY : Rockefeller Univ. Press, 1962
• Jahr Quelle: 2012
• Band/Heft Quelle: 197(2012), 1, Seite 59-74
• ISSN Quelle: 1540-8140
• DOI: doi:10.1083/jcb.201111123
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 158133429X

Abstract

Microtubule nucleation sites in yeast consist of a ring of γ-tubulin small complexes and a slight excess of uncomplexed γ-tubulin., γ-Tubulin complexes are essential for microtubule (MT) nucleation. The γ-tubulin small complex (γ-TuSC) consists of two molecules of γ-tubulin and one molecule each of Spc97 and Spc98. In vitro, γ-TuSCs oligomerize into spirals of 13 γ-tubulin molecules per turn. However, the properties and numbers of γ-TuSCs at MT nucleation sites in vivo are unclear. In this paper, we show by fluorescence recovery after photobleaching analysis that γ-tubulin was stably integrated into MT nucleation sites and was further stabilized by tubulin binding. Importantly, tubulin showed a stronger interaction with the nucleation site than with the MT plus end, which probably provides the basis for MT nucleation. Quantitative analysis of γ-TuSCs on single MT minus ends argued for nucleation sites consisting of approximately seven γ-TuSCs with approximately three additional γ-tubulin molecules. Nucleation and anchoring of MTs required the same number of γ-tubulin molecules. We suggest that a spiral of seven γ-TuSCs with a slight surplus of γ-tubulin nucleates MTs in vivo.