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

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...

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Hauptverfasser: Erlemann, Sarah (VerfasserIn) , Neuner, Annett (VerfasserIn) , Gombos, Linda (VerfasserIn) , Schiebel, Elmar (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 2 April, 2012
In: The journal of cell biology
Year: 2012, Jahrgang: 197, Heft: 1, Pages: 59-74
ISSN:1540-8140
DOI:10.1083/jcb.201111123
Online-Zugang:Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1083/jcb.201111123
Verlag, kostenfrei, Volltext: https://rupress.org/jcb/article/197/1/59/36846/An-extended-tubulin-ring-functions-as-a-stable
Volltext
Verfasserangaben:Sarah Erlemann, Annett Neuner, Linda Gombos, Romain Gibeaux, Claude Antony, and Elmar Schiebel
Beschreibung
Zusammenfassung: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.
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Beschreibung:Online Resource
ISSN:1540-8140
DOI:10.1083/jcb.201111123