title: Mathematical model of the morphogenesis checkpoint in budding yeast.
abstract: The morphogenesis checkpoint in budding yeast delays progression through the cell cycle in response to stimuli that prevent bud formation. Central to the checkpoint mechanism is Swe1 kinase: normally inactive, its activation halts cell cycle progression in G2. We propose a molecular network for Swe1 control, based on published observations of budding yeast and analogous control signals in fission yeast. The proposed Swe1 network is merged with a model of cyclin-dependent kinase regulation, converted into a set of differential equations and studied by numerical simulation. The simulations accurately reproduce the phenotypes of a dozen checkpoint mutants. Among other predictions, the model attributes a new role to Hsl1, a kinase known to play a role in Swe1 degradation: Hsl1 must also be indirectly responsible for potent inhibition of Swe1 activity. The model supports the idea that the morphogenesis checkpoint, like other checkpoints, raises the cell size threshold for progression from one phase of the cell cycle to the next.
authors.affiliation: Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ciliberto
authors.forename: Bela
authors.initials: B
authors.lastname: Novak
authors.forename: John J
authors.initials: JJ
authors.lastname: Tyson
mesh_terms: D000465:Algorithms; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000235:genetics; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D018816:Genes, cdc / Q000502:physiology*; D008954:Models, Biological; D009024:Morphogenesis; D009154:Mutation / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; C099685:SWE1 protein, S cerevisiae; D011505:Protein-Tyrosine Kinases; C106494:HSL1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D018844:Cyclin-Dependent Kinases