title: A novel function of Saccharomyces cerevisiae CDC5 in cytokinesis.
abstract: Coordination of mitotic exit with timely initiation of cytokinesis is critical to ensure completion of mitotic events before cell division. The Saccharomyces cerevisiae polo kinase Cdc5 functions in a pathway leading to the degradation of mitotic cyclin Clb2, thereby permitting mitotic exit. Here we provide evidence that Cdc5 also plays a role in regulating cytokinesis and that an intact polo-box, a conserved motif in the noncatalytic COOH-terminal domain of Cdc5, is required for this event. Depletion of Cdc5 function leads to an arrest in cytokinesis. Overexpression of the COOH-terminal domain of Cdc5 (cdc5DeltaN), but not the corresponding polo-box mutant, resulted in connected cells. These cells shared cytoplasms with incomplete septa, and possessed aberrant septin ring structures. Provision of additional copies of endogenous CDC5 remedied this phenotype, suggesting a dominant-negative inhibition of cytokinesis. The polo-box-dependent interactions between Cdc5 and septins (Cdc11 and Cdc12) and genetic interactions between the dominant-negative cdc5DeltaN and Cyk2/Hof1 or Myo1 suggest that direct interactions between cdc5DeltaN and septins resulted in inhibition of Cyk2/Hof1- and Myo1-mediated cytokinetic pathways. Thus, we propose that Cdc5 may coordinate mitotic exit with cytokinesis by participating in both anaphase promoting complex activation and a polo-box-dependent cytokinetic pathway.
authors.affiliation: Laboratory of Metabolism, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: S
authors.initials: S
authors.lastname: Song
authors.forename: K S
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000199:Actins / Q000378:metabolism; D020816:Amino Acid Motifs; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics / Q000502:physiology*; D048429:Cell Size; D003598:Cytoskeletal Proteins; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009154:Mutation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques
chemical_list: D000199:Actins; C099502:CDC11 protein, S cerevisiae; C099504:CDC12 protein, S cerevisiae; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; C116847:HOF1 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C081927:CDC5 protein, S cerevisiae