title: Bni5p, a septin-interacting protein, is required for normal septin function and cytokinesis in Saccharomyces cerevisiae.
abstract: In the budding yeast Saccharomyces cerevisiae, the Cdc3p, Cdc10p, Cdc11p, Cdc12p, and Sep7p/Shs1p septins assemble early in the cell cycle in a ring that marks the future cytokinetic site. The septins appear to be major structural components of a set of filaments at the mother-bud neck and function as a scaffold for recruiting proteins involved in cytokinesis and other processes. We isolated a novel gene, BNI5, as a dosage suppressor of the cdc12-6 growth defect. Overexpression of BNI5 also suppressed the growth defects of cdc10-1, cdc11-6, and sep7Delta strains. Loss of BNI5 resulted in a cytokinesis defect, as evidenced by the formation of connected cells with shared cytoplasms, and deletion of BNI5 in a cdc3-6, cdc10-1, cdc11-6, cdc12-6, or sep7Delta mutant strain resulted in enhanced defects in septin localization and cytokinesis. Bni5p localizes to the mother-bud neck in a septin-dependent manner shortly after bud emergence and disappears from the neck approximately 2 to 3 min before spindle disassembly. Two-hybrid, in vitro binding, and protein-localization studies suggest that Bni5p interacts with the N-terminal domain of Cdc11p, which also appears to be sufficient for the localization of Cdc11p, its interaction with other septins, and other critical aspects of its function. Our data suggest that the Bni5p-septin interaction is important for septin ring stability and function, which is in turn critical for normal cytokinesis.
authors.affiliation: Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA.
authors.forename: Philip R
authors.initials: PR
authors.lastname: Lee
authors.forename: Sukgil
authors.initials: S
authors.lastname: Song
authors.forename: Hyeon-Su
authors.initials: HS
authors.lastname: Ro
authors.forename: Chong J
authors.initials: CJ
authors.lastname: Park
authors.forename: John
authors.initials: J
authors.lastname: Lippincott
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.forename: John R
authors.initials: JR
authors.lastname: Pringle
authors.forename: Claudio
authors.initials: C
authors.lastname: De Virgilio
authors.forename: Mark S
authors.initials: MS
authors.lastname: Longtine
authors.forename: Kyung S
authors.initials: KS
authors.lastname: Lee
mesh_terms: D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020558:GTP Phosphohydrolases; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009154:Mutation; D019683:Penetrance; D010957:Plasmids / Q000235:genetics; D051304:Profilins; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D013696:Temperature; D014157:Transcription Factors; D020798:Two-Hybrid System Techniques
chemical_list: C466084:BNI5 protein, S cerevisiae; C099502:CDC11 protein, S cerevisiae; C099504:CDC12 protein, S cerevisiae; C086662:CDC3 protein, S cerevisiae; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; C116847:HOF1 protein, S cerevisiae; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D051304:Profilins; D011993:Recombinant Fusion Proteins; C115656:SHS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C061178:cdc10 protein, S pombe; C512892:CDC10 protein, S cerevisiae; D020558:GTP Phosphohydrolases