title: Shs1 plays separable roles in septin organization and cytokinesis in Saccharomyces cerevisiae.
abstract: In Saccharomyces cerevisiae, five septins (Cdc3, Cdc10, Cdc11, Cdc12, and Shs1/Sep7) form the septin ring at the bud neck during vegetative growth. We show here that disruption of SHS1 caused cold-sensitive growth in the W303 background, with cells arrested in chains, indicative of a cytokinesis defect. Surprisingly, the other four septins appeared to form an apparently normal septin ring in shs1Delta cells grown under the restrictive condition. We found that Myo1 and Iqg1, two components of the actomyosin contractile ring, and Cyk3, a component of the septum formation, were either delocalized or mislocalized in shs1Delta cells, suggesting that Shs1 plays supportive roles in cytokinesis. We also found that deletion of SHS1 enhanced or suppressed the septin defect in cdc10Delta and cdc11Delta cells, respectively, suggesting that Shs1 is involved in septin organization, exerting different effects on septin-ring assembly, depending on the composition of the septin subunits. Furthermore, we constructed an shs1-100c allele that lacks the coding sequence for the C-terminal 32 amino acids. This allele still displayed the genetic interactions with the septin mutants, but did not show cytokinesis defects as described above, suggesting that the roles of Shs1 in septin organization and cytokinesis are separable.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Iwase
authors.forename: Jianying
authors.initials: J
authors.lastname: Luo
authors.forename: Erfei
authors.initials: E
authors.lastname: Bi
authors.forename: Akio
authors.initials: A
authors.lastname: Toh-e
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: C099502:CDC11 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; C115656:SHS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C512892:CDC10 protein, S cerevisiae; D020558:GTP Phosphohydrolases