A novel functional domain of Cdc15 kinase is required for its interaction with Tem1 GTPase in Saccharomyces cerevisiae.
Exit from mitosis requires the inactivation of cyclin-dependent kinase (CDK) activity. In the budding yeast Saccharomyces cerevisiae, a number of gene products have been identified as components of the signal transduction network regulating inactivation of CDK (called the MEN, for the mitotic exit network). Cdc15, one of such components of the MEN, is an essential protein kinase. By the two-hybrid screening, we identified Cdc15 as a binding protein of Tem1 GTPase, another essential regulator of the MEN. Coprecipitation experiments revealed that Tem1 binds to Cdc15 in vivo. By deletion analysis, we found that the Tem1-binding domain resides near the conserved kinase domain of Cdc15. The cdc15-LF mutation, which was introduced into the Tem1-binding domain, reduced the interaction with Cdc15 and Tem1 and caused temperature-sensitive growth. The kinase activity of Cdc15 was not so much affected by the cdc15-LF mutation. However, Cdc15-LF failed to localize to the SPB at the restrictive temperature. Our data show that the interaction with Tem1 is important for the function of Cdc15 and that Cdc15 and Tem1 function in a complex to direct the exit from mitosis.
Asakawa
Kazuhide
K
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
Yoshida
Satoshi
S
Otake
Fumiaki
F
Toh-e
Akio
A
D000595:Amino Acid Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016296:Mutagenesis; D011494:Protein Kinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D008941:Spindle Apparatus / Q000378:metabolism
C082279:CDC15 protein; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; C089965:TEM1 protein, S cerevisiae; D011494:Protein Kinases; D019204:GTP-Binding Proteins; D020559:Monomeric GTP-Binding Proteins