title: Requirement for Bbp1p in the proper mitotic functions of Cdc5p in Saccharomyces cerevisiae.
abstract: The polo-box domain of the budding yeast polo kinase Cdc5p plays an essential role for targeting the catalytic activity of Cdc5p to spindle pole bodies (SPBs) and cytokinetic neck-filaments. Here, we report the isolation of Bbp1p as a polo-box interacting protein by a yeast two-hybrid screen. Bbp1p localizes to the periphery of the central plaque of the SPB and plays an important role in SPB duplication. Similarly, Cdc5p localized to the cytoplasmic periphery of the SPB. In vitro binding studies showed that Cdc5p interacted with the N-terminal domain of Bbp1p (Bbp1pDeltaC), but apparently not with Mps2p, a component shown to form a stable complex with Bbp1p. In addition, Bbp1p, but likely not Mps2p, was required for proper localization of Cdc5p to the SPB. The C-terminal coiled-coil domain of Bbp1p (Bbp1p(243-385)), which is crucial for both the homodimerization and the SPB localization, could target the localization-defective Cdc5pDeltaC to the SPB and induce the release of Cdc14p from the nucleolus. Consistent with this observation, expression of CDC5DeltaC-BBP1(243-385) under CDC5 promoter control partially complemented the cdc5Delta defect. These data suggest that Bbp1pDeltaC interacts with the polo-box domain of Cdc5p, and this interaction is critical for the subcellular localization and mitotic functions of Cdc5p.
authors.affiliation: Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Chong J
authors.initials: CJ
authors.lastname: Park
authors.forename: Sukgil
authors.initials: S
authors.lastname: Song
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Giddings
authors.forename: Hyeon-Su
authors.initials: HS
authors.lastname: Ro
authors.forename: Krisada
authors.initials: K
authors.lastname: Sakchaisri
authors.forename: Jung-Eun
authors.initials: JE
authors.lastname: Park
authors.forename: Yeon-Sun
authors.initials: YS
authors.lastname: Seong
authors.forename: Mark
authors.initials: M
authors.lastname: Winey
authors.forename: Kyung S
authors.initials: KS
authors.lastname: Lee
mesh_terms: D002384:Catalysis; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000502:physiology*; D002455:Cell Division; D002466:Cell Nucleolus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D019281:Dimerization; D005838:Genotype; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008868:Microtubule Proteins / Q000502:physiology*; D008938:Mitosis; D008954:Models, Biological; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000502:physiology*; D008941:Spindle Apparatus; D013696:Temperature; D013997:Time Factors; D020798:Two-Hybrid System Techniques
chemical_list: C404863:BBP1 protein, S cerevisiae; C074860:CDC14 protein, S cerevisiae; C513239:CEF1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D008164:Luminescent Proteins; D008868:Microtubule Proteins; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D005982:Glutathione Transferase; D017027:Protein Tyrosine Phosphatases