Phosphorylation and spindle pole body localization of the Cdc15p mitotic regulatory protein kinase in budding yeast.
Cdc15p is an essential protein kinase and functions with a group of late mitotic proteins that includes Lte1p, Tem1p, Cdc14p and Dbf2p/Dbf20p to inactivate Cdc28p-Clb2p at the end of mitosis in budding yeast [1] [2]. Cdc14p is activated and released from the nucleolus at late anaphase/telophase to dephosphorylate important regulators ... of Cdc28p-Clb2p such as Hct1p/Cdh1p, Sic1p and Swi5p in a CDC15-dependent manner [3] [4] [5] [6] [7]. How Cdc15p itself is regulated is not known. Here, we report that both the phosphorylation and localization of Cdc15p are cell cycle regulated. The extent of phosphorylation of Cdc15p gradually increases during cell-cycle progression until some point during late anaphase/telophase when it is rapidly dephosphorylated. We provide evidence suggesting that Cdc14p is the phosphatase responsible for the dephosphorylation of Cdc15p. Using a Cdc15p fusion protein coupled at its carboxyl terminus to green fluorescent protein (GFP), we found that Cdc15p, like its homologue Cdc7p [8] in fission yeast, localizes to the spindle pole bodies (SPBs) during mitosis. At the end of telophase, a portion of Cdc15p is located at the mother-bud neck, suggesting a possible role for Cdc15p in cytokinesis.
Mesh Terms:
Cell Cycle, Cell Cycle Proteins, Fungal Proteins, GTP-Binding Proteins, Mitosis, Mitotic Spindle Apparatus, Phosphoprotein Phosphatases, Phosphorylation, Protein Kinases, Protein Tyrosine Phosphatases, Recombinant Fusion Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
Cell Cycle, Cell Cycle Proteins, Fungal Proteins, GTP-Binding Proteins, Mitosis, Mitotic Spindle Apparatus, Phosphoprotein Phosphatases, Phosphorylation, Protein Kinases, Protein Tyrosine Phosphatases, Recombinant Fusion Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
Curr. Biol.
Date: Mar. 23, 2000
PubMed ID: 10744974
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