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: In interphase cells, cytoplasmic MTs are known to be extremely dynamic as they rapidly alternate periods of growth and shrinkage (Fig. 2 A; Drummond and Cross, 2000). They are therefore very sensitive to drugs that inhibit MT polymerization and cause dynamic MT disassembly, such as methyl benzimidazol-2-yl-carbamate (MBC) or thiabendazole (TBZ; Fig. 2 B; Sawin and Nurse, 1998; Sawin and Snaith, 2004). In contrast, we showed that in quiescent cells, the Q-MT bundle had a constant length (Fig. 2 A) and resisted against massive amounts of drugs (Fig. 2 B) or a cold treatment known to cause the disassembly of dynamic MTs (Fig. S2, A and B). Importantly, no fluorescence was recovered after GFP-Atb2 photobleaching, demonstrating that within the Q-MT bundle, not only MTs were stable but also there was no MT sliding (Fig. 2 C). Of note, like cells entering quiescence upon carbon source exhaustion, upon nitrogen starvation, cells also stabilized a unique MT bundle (Fig. S2 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.