title: Phosphorylation-dependent septin interaction of Bni5 is important for cytokinesis.
abstract: In budding yeast, septin plays as a scaffold to recruits protein components and regulates crucial cellular events including bud site selection, bud morphogenesis, Cdc28 activation pathway, and cytokinesis. Phosphorylation of Bni5 isolated as a suppressor for septin defect is essential to Swe1-dependent regulation of bud morphogenesis and mitotic entry. The mechanism by which Bni5 regulates normal septin function is not completely understood. Here, we provide evidence that Bni5 phosphorylation is important for interaction with septin component Cdc11 and for timely delocalization from septin filament at late mitosis. Phosphorylation-deficient bni5-4A was synthetically lethal with hof1Delta. bni5-4A cells had defective structure of septin ring and connected cell morphology, indicative of defects in cytokinesis. Two-hybrid analysis revealed that bni5-4A has a defect in direct interaction with Cdc11 and Cdc12. GFP-tagged bni5-4A was normally localized at mother-bud neck of budded cells before middle of mitosis. In contrast, at large-budded telophase cells, bni5-4A-GFP was defective in localization and disappeared from the neck approximately 2 min earlier than that of wild type, as evidenced by time-lapse analysis. Therefore, earlier delocalization of bni5-4A from septin filament is consistent with phosphorylation-dependent interaction with the septin component. These results suggest that timely delocalization of Bni5 by phosphorylation is important for septin function and regulation of cytokinesis.
authors.affiliation: Research and Development Center, Pigeon, Chopyeongmyeon, Jincheon, Chungbuk, Republic of Korea.
authors.forename: Sung Chang
authors.initials: SC
authors.lastname: Nam
authors.forename: Hyeran
authors.initials: H
authors.lastname: Sung
authors.forename: Seung Hye
authors.initials: SH
authors.lastname: Kang
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Joo
authors.forename: Soo Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Yeon Bok
authors.initials: YB
authors.lastname: Chung
authors.forename: Chong-Kil
authors.initials: CK
authors.lastname: Lee
authors.forename: Sukgil
authors.initials: S
authors.lastname: Song
mesh_terms: D019677:Artificial Gene Fusion; D018797:Cell Cycle Proteins / Q000378:metabolism*; D048749:Cytokinesis; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D020043:Genes, Essential; D005800:Genes, Fungal; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D020125:Mutation, Missense; D010766:Phosphorylation; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: C466084:BNI5 protein, S cerevisiae; C099502:CDC11 protein, S cerevisiae; C099504:CDC12 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins