Eavesdropping on the cytoskeleton: progress and controversy in the yeast morphogenesis checkpoint.
The morphogenesis checkpoint provides a link between bud formation and mitosis in yeast. In this pathway, insults affecting the actin or septin cytoskeleton trigger a cell cycle arrest, mediated by the Wee1 homolog Swe1p, which catalyzes the inhibitory phosphorylation of the mitosis-promoting cyclin-dependent kinase (CDK) on a conserved tyrosine residue. Analyses of Swe1p phosphorylation have mapped 61 sites targeted by CDKs and Polo-related kinases, which control both Swe1p activity and Swe1p degradation. Although the sites themselves are not evolutionarily conserved, the control of Swe1p degradation exhibits many conserved features, and is linked to DNA-responsive checkpoints in vertebrate cells. At the 'sensing' end of the checkpoint, recent work has begun to shed light on how septins are organized and how they impact Swe1p regulators. However, the means by which Swe1p responds to actin perturbations once a bud has formed remains controversial.
Keaton
Mignon A
MA
Department of Pharmacology and Cancer Biology, Box 3813, Duke University Medical Center, Durham, NC 27710, USA.
Lew
Daniel J
DJ
D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D003599:Cytoskeleton / Q000378:metabolism*; D009024:Morphogenesis; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000201:enzymology / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins
D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; C099685:SWE1 protein, S cerevisiae; D011505:Protein-Tyrosine Kinases; D017489:CDC28 Protein Kinase, S cerevisiae