Requirement for the Budding Yeast Polo Kinase Cdc5 in Proper Microtubule Growth and Dynamics

Abstract

In many organisms, polo kinases appear to play multiple roles during M-phase progression. To provide new insights into the function of the budding yeast polo kinase Cdc5, we generated novel temperature-sensitive cdc5 mutants by mutagenizing the C-terminal noncatalytic polo box domain, a region that is critical for proper subcellular localization. One of these mutants, cdc5-11, exhibited a temperature-sensitive growth defect with an abnormal spindle morphology. Strikingly, provision of a moderate level of benomyl, a microtubule-depolymerizing drug, permitted cdc5-11 cells to grow significantly better than the isogenic CDC5 wild type in a FEAR (cdc Fourteen Early Anaphase Release)-independent manner. In addition, cdc5-11 required MAD2 for both cell growth and the benomyl-remedial phenotype. These results suggest that cdc5-11 is defective in proper spindle function. Consistent with this view, cdc5-11 exhibited abnormal spindle morphology, shorter spindle length, and delayed microtubule regrowth at the nonpermissive temperature. Overexpression of CDC5 moderately rescued the spc98-2 growth defect. Interestingly, both Cdc28 and Cdc5 were required for the proper modification of the spindle pole body components Nud1, Slk19, and Stu2 in vivo. They also phosphorylated these three proteins in vitro. Taken together, these observations suggest that concerted action of Cdc28 and Cdc5 on Nud1, Slk19, and Stu2 is important for proper spindle functions.

Orthologues of the Anaphase-Promoting Complex/Cyclosome Coactivators Cdc20p and Cdh1p Are Important for Mitotic Progression and Morphogenesis in Candida albicans

“…In support of this, Cdc20p and Cdc5p directly or indirectly interact in S. cerevisiae (67) and higher organisms (44,50), respectively. Polo-like kinases can also act upstream of the spindle assembly checkpoint (SAC) factor Mad2p in other systems (1,47), which binds and inactivates Cdc20p (87). Our demonstration that Cdc5p-TAP increased during depletion of Cdc20p may reflect an indirect effect of mitotic arrest.…”

Polo-Like Kinase Is Expressed in S/G 2 /M Phase and Associated with the Flagellum Attachment Zone in both Procyclic and Bloodstream Forms of Trypanosoma brucei

“…The single localization of TbPLK to the dorsal spots of cells thus distinguishes it from all the other known PLKs, which could be due to the sole function of TbPLK in regulating only the cytokinesis in trypanosomes (16,24). This limited function of TbPLK could be due to the fact that none of the Cdc5 substrates that appear to play a role in controlling the mitosis of yeast (33,44) or the proteins involving PLKs in mitosis in metazoans (12,20,35,36,41,46) can find a structural homologue in the T. brucei genome database (4). An Aurora B homologue (TbAUK1) in the trypanosome plays important roles in controlling both mitosis and cytokinesis (27,47).…”

Independent modulation of the kinase and polo-box activities of Cdc5 protein unravels unique roles in the maintenance of genome stability

“…First, loss of ploidy control is frequently observed in mutants defective in the regulation of SPB components (e.g., 12). Second, multiple components of the SPB are regulated by Cdc5- mediated phosphorylation (22,32,33). Third, Cdc5 localizes to SPBs (6,24) and interacts physically with multiple SPB components (22,33,34).…”

“…Second, multiple components of the SPB are regulated by Cdc5- mediated phosphorylation (22,32,33). Third, Cdc5 localizes to SPBs (6,24) and interacts physically with multiple SPB components (22,33,34). Fourth, mutants of SPB outer plaque components that are known to interact physically with Cdc5 [i.e., Spc72, Cnm67 (22,34)] show an uncommon age-dependent increase in ploidy that is reminiscent of the progressive changes in ploidy experienced by cdc5-16 cells (35).…”