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A stable microtubule array drives fission yeast polarity reestablishment upon quiescence exit.

Laporte D, Courtout F, Pinson B, Dompierre J, Salin B, Brocard L, Sagot I - J. Cell Biol. (2015)

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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, 33000 Bordeaux, France Centre National de la Recherche Scientifique, UMR5095 Bordeaux, 33077 Bordeaux, France.

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Quiescent S. pombe cells have lost their polarity and reorganized their actin cytoskeleton into actin bodies. Cells expressing either Atb2-GFP or the polarity markers Tea1-GFP or Tip1-GFP (A), GFP-CRIB or the exocyst component Exo70-GFP or Sec8-GFP (B), or Fim1-GFP or Acp2-GFP (C) are shown upon entry into quiescence. F-actin filaments were detected by Alexa-Phalloidin staining (C, bottom). Red arrows point at actin bodies. Bars, 2 µm.
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fig6: Quiescent S. pombe cells have lost their polarity and reorganized their actin cytoskeleton into actin bodies. Cells expressing either Atb2-GFP or the polarity markers Tea1-GFP or Tip1-GFP (A), GFP-CRIB or the exocyst component Exo70-GFP or Sec8-GFP (B), or Fim1-GFP or Acp2-GFP (C) are shown upon entry into quiescence. F-actin filaments were detected by Alexa-Phalloidin staining (C, bottom). Red arrows point at actin bodies. Bars, 2 µm.

Mentions: In actively dividing S.pombe, MTs deposit polarity factors, such as Tea1, to the cell tip to allow polarized growth (Chang and Martin, 2009; Martin, 2009; Piel and Tran, 2009; Hachet et al., 2012). In quiescent S. pombe cells, Tea1 was no longer detected at the cell tips but was rather localized onto the Q-MT bundle (Fig. 6 A). Tip1, a MT plus end tracking protein of the CLIP170 family, was also lost from cell extremities but couldn’t be detected in quiescent cells (Fig. 6 A). We made a similar observation for active Cdc42 (CRIB domain), the exocyst components Exo70 and Sec8 (Fig. 6 B), the myosin V myo52, the polarity factor Pob1 (Fig. S5 A), and the formin For3 (not depicted). Interestingly, in quiescent S. pombe, no actin cable or patch were found. Instead, we observed a big cytoplasmic F-actin–containing structure (Fig. 6 C). This structure displayed all the characteristics described for actin bodies in quiescent S. cerevisiae (Sagot et al., 2006): they do not have a particular size or shape (Fig. 6 C), they are resistant to Latrunculin A (not depicted), and they contain a specific set of actin binding proteins such as fimbrin (Fim1; Fig. 6 C), capping protein (Acp2; Fig. 6 C), and drebrin (Aap1; Fig. S5 A), but not Bud6, Vrp1, Crn1, Arp5, or End4 (Fig. S5 A). These observations indicated that upon glucose exhaustion–induced quiescence entry, S. pombe cells lose their polarity and entirely reorganize their actin cytoskeleton.


A stable microtubule array drives fission yeast polarity reestablishment upon quiescence exit.

Laporte D, Courtout F, Pinson B, Dompierre J, Salin B, Brocard L, Sagot I - J. Cell Biol. (2015)

Quiescent S. pombe cells have lost their polarity and reorganized their actin cytoskeleton into actin bodies. Cells expressing either Atb2-GFP or the polarity markers Tea1-GFP or Tip1-GFP (A), GFP-CRIB or the exocyst component Exo70-GFP or Sec8-GFP (B), or Fim1-GFP or Acp2-GFP (C) are shown upon entry into quiescence. F-actin filaments were detected by Alexa-Phalloidin staining (C, bottom). Red arrows point at actin bodies. Bars, 2 µm.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4494004&req=5

fig6: Quiescent S. pombe cells have lost their polarity and reorganized their actin cytoskeleton into actin bodies. Cells expressing either Atb2-GFP or the polarity markers Tea1-GFP or Tip1-GFP (A), GFP-CRIB or the exocyst component Exo70-GFP or Sec8-GFP (B), or Fim1-GFP or Acp2-GFP (C) are shown upon entry into quiescence. F-actin filaments were detected by Alexa-Phalloidin staining (C, bottom). Red arrows point at actin bodies. Bars, 2 µm.
Mentions: In actively dividing S.pombe, MTs deposit polarity factors, such as Tea1, to the cell tip to allow polarized growth (Chang and Martin, 2009; Martin, 2009; Piel and Tran, 2009; Hachet et al., 2012). In quiescent S. pombe cells, Tea1 was no longer detected at the cell tips but was rather localized onto the Q-MT bundle (Fig. 6 A). Tip1, a MT plus end tracking protein of the CLIP170 family, was also lost from cell extremities but couldn’t be detected in quiescent cells (Fig. 6 A). We made a similar observation for active Cdc42 (CRIB domain), the exocyst components Exo70 and Sec8 (Fig. 6 B), the myosin V myo52, the polarity factor Pob1 (Fig. S5 A), and the formin For3 (not depicted). Interestingly, in quiescent S. pombe, no actin cable or patch were found. Instead, we observed a big cytoplasmic F-actin–containing structure (Fig. 6 C). This structure displayed all the characteristics described for actin bodies in quiescent S. cerevisiae (Sagot et al., 2006): they do not have a particular size or shape (Fig. 6 C), they are resistant to Latrunculin A (not depicted), and they contain a specific set of actin binding proteins such as fimbrin (Fim1; Fig. 6 C), capping protein (Acp2; Fig. 6 C), and drebrin (Aap1; Fig. S5 A), but not Bud6, Vrp1, Crn1, Arp5, or End4 (Fig. S5 A). These observations indicated that upon glucose exhaustion–induced quiescence entry, S. pombe cells lose their polarity and entirely reorganize their actin cytoskeleton.

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.

View Article: PubMed Central - HTML - PubMed

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
Related in: MedlinePlus