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γ‐Tubulin Ring Complexes and EB1 play antagonistic roles in microtubule dynamics and spindle positioning
Author(s) -
Bouissou Anaїs,
Vérollet Christel,
Forges Hélène,
Haren Laurence,
Bellaїche Yohanns,
Perez Franck,
Merdes Andreas,
RaynaudMessina Brigitte
Publication year - 2014
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/embj.201385967
Subject(s) - biology , microtubule , tubulin , microbiology and biotechnology , ring (chemistry) , microtubule nucleation , dynamics (music) , microtubule associated protein , centrosome , genetics , cell , cell cycle , organic chemistry , acoustics , chemistry , physics
γ‐Tubulin is critical for microtubule ( MT ) assembly and organization. In metazoa, this protein acts in multiprotein complexes called γ‐ T ubulin R ing C omplexes (γ‐ T u RC s). While the subunits that constitute γ‐ T ubulin S mall C omplexes (γ‐ T u SC s), the core of the MT nucleation machinery, are essential, mutation of γ‐ T u RC ‐specific proteins in Drosophila causes sterility and morphological abnormalities via hitherto unidentified mechanisms. Here, we demonstrate a role of γ‐ T u RC s in controlling spindle orientation independent of MT nucleation activity, both in cultured cells and in vivo , and examine a potential function for γ‐ T u RC s on astral MT s. γ‐ T u RC s locate along the length of astral MT s, and depletion of γ‐ T u RC ‐specific proteins increases MT dynamics and causes the plus‐end tracking protein EB 1 to redistribute along MT s. Moreover, suppression of MT dynamics through drug treatment or EB 1 down‐regulation rescues spindle orientation defects induced by γ‐ T u RC depletion. Therefore, we propose a role for γ‐ T u RC s in regulating spindle positioning by controlling the stability of astral MT s.