title: Role of the septin ring in the asymmetric localization of proteins at the mother-bud neck in Saccharomyces cerevisiae.
abstract: In the yeast Saccharomyces cerevisiae, septins form a scaffold in the shape of a ring at the future budding site that rearranges into a collar at the mother-bud neck. Many proteins bind asymmetrically to the septin collar. We found that the protein Bni4-CFP was located on the exterior of the septin ring before budding and on the mother side of the collar after budding, whereas the protein kinase Kcc4-YFP was located on the interior of the septin ring before budding and moved into the bud during the formation of the septin collar. Unbudded cells treated with the actin inhibitor latrunculin-A assembled cortical caps of septins on which Bni4-CFP and Kcc4-YFP colocalized. Bni4-CFP and Kcc4-YFP also colocalized on cortical caps of septins found in strains deleted for the genes encoding the GTPase activating proteins of Cdc42 (RGA1, RGA2, and BEM3). However, Bni4-CFP and Kcc4-YFP were still partially separated in mutants (gin4, elm1, cla4, and cdc3-1) in which septin morphology was severely disrupted in other ways. These observations provide clues to the mechanisms for the asymmetric localization of septin-associated proteins.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Kozubowski
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Larson
authors.forename: Kelly
authors.initials: K
authors.lastname: Tatchell
mesh_terms: D000199:Actins / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D016764:Cell Polarity; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D048749:Cytokinesis; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D051304:Profilins / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000199:Actins; C494956:Bni4p protein, S cerevisiae; D019086:Bridged Bicyclo Compounds, Heterocyclic; C099502:CDC11 protein, S cerevisiae; C099504:CDC12 protein, S cerevisiae; C086662:CDC3 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D051304:Profilins; C115656:SHS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013844:Thiazoles; D053778:Thiazolidines; D011494:Protein Kinases; C411302:ELM1 protein, S cerevisiae; C107283:GIN4 protein, S cerevisiae; C117190:KCC4 protein, S cerevisiae; D018844:Cyclin-Dependent Kinases; C037067:latrunculin A