A stable microtubule array drives fission yeast polarity reestablishment upon quiescence exit.
Bottom Line: Astonishingly, MTs are also stabilized and rearranged into a novel antiparallel bundle associated with the spindle pole body, named Q-MT bundle.Finally and importantly, we reveal that Q-MT bundle elongation is involved in polarity reestablishment upon quiescence exit and thereby the efficient return to the proliferative state.Our work demonstrates that quiescent S. pombe cells assemble specific cytoskeleton structures that improve the swiftness of the transition back to proliferation.
Affiliation: Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, 33000 Bordeaux, France Centre National de la Recherche Scientifique, UMR5095 Bordeaux, 33077 Bordeaux, France.Show MeSH
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Mentions: We then analyzed the effect of MAP encoding gene deletion on the Q-MT bundle shape, stability, and formation. None of the deletions tested resulted in the absence of MT bundle (Fig. 4 D) or its destabilization (Fig. S3 C). However, in some mutants, whereas the steady-state level of total α-tubulin remained constant (Fig. S3 B), the Q-MT bundle was either both thicker and longer (klp5Δklp6Δ, alp7Δ, and dis1Δ), just thinner (ase1Δ), or both shorter and thinner (mal3Δ and alp14Δ; Fig. 4, E and F). These results indicated that MAPs involved in interphase MT length regulation are also involved in shaping the Q-MT bundle in quiescence. Besides, mutants with an altered Q-MT shape did not display mortality in quiescence (Fig. S3 D) nor a cell shape defect upon quiescence exit (Fig. S3 E), with the exception of alp14Δ cells (see the following paragraph and Fig. 7 C).
Affiliation: Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, 33000 Bordeaux, France Centre National de la Recherche Scientifique, UMR5095 Bordeaux, 33077 Bordeaux, France.