title: A morphogenesis checkpoint monitors the actin cytoskeleton in yeast.
abstract: A morphogenesis checkpoint in budding yeast delays cell cycle progression in response to perturbations of cell polarity that prevent bud formation (Lew, D.J., and S.I. Reed. 1995. J. Cell Biol. 129:739- 749). The cell cycle delay depends upon the tyrosine kinase Swe1p, which phosphorylates and inhibits the cyclin-dependent kinase Cdc28p (Sia, R.A.L., H.A. Herald, and D.J. Lew. 1996. Mol. Biol. Cell. 7:1657- 1666). In this report, we have investigated the nature of the defect(s) that trigger this checkpoint. A Swe1p- dependent cell cycle delay was triggered by direct perturbations of the actin cytoskeleton, even when polarity establishment functions remained intact. Furthermore, actin perturbation could trigger the checkpoint even in cells that had already formed a bud, suggesting that the checkpoint directly monitors actin organization, rather than (or in addition to) polarity establishment or bud formation. In addition, we show that the checkpoint could detect actin perturbations through most of the cell cycle. However, the ability to respond to such perturbations by delaying cell cycle progression was restricted to a narrow window of the cell cycle, delimited by the periodic accumulation of the checkpoint effector, Swe1p.
authors.affiliation: Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: J N
authors.initials: JN
authors.lastname: McMillan
authors.forename: R A
authors.initials: RA
authors.lastname: Sia
authors.forename: D J
authors.initials: DJ
authors.lastname: Lew
mesh_terms: D000199:Actins / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000187:drug effects; D003599:Cytoskeleton / Q000378:metabolism; D009024:Morphogenesis; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; D013844:Thiazoles; D053778:Thiazolidines; C099685:SWE1 protein, S cerevisiae; D011505:Protein-Tyrosine Kinases; C037067:latrunculin A