The Dcr2p phosphatase destabilizes Sic1p in Saccharomyces cerevisiae.
Initiation of cell division is controlled by an irreversible switch. In Saccharomyces cerevisiae degradation of the Sic1p protein, an inhibitor of mitotic cyclin/cyclin-dependent kinase complexes, takes place before initiation of DNA replication, at a point called START. Sic1p is phosphorylated by multiple kinases, which can differentially affect the stability of Sic1p. How phosphorylations that stabilize Sic1p are reversed is unknown. Here we show that the Dcr2p phosphatase functionally and physically interacts with Sic1p. Over-expression of Dcr2p destabilizes Sic1p and leads to phenotypes associated with destabilized Sic1p, such as genome instability. Our results identify a novel factor that affects the stability of Sic1p, possibly contributing to mechanisms that trigger initiation of cell division.
Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843, USA.
Ritu
R
Pathak
Heidi M
HM
Blank
Jinbai
J
Guo
Sarah
S
Ellis
Michael
M
Polymenis
D002453:Cell Cycle; D043171:Chromosomal Instability; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D010641:Phenotype; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
D050756:Cyclin-Dependent Kinase Inhibitor Proteins; C086926:SIC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C501514:Dcr2 protein, S cerevisiae; D010744:Phosphoric Monoester Hydrolases