Arg-Pro-X-Ser/Thr Is a Consensus Phosphoacceptor Sequence for the Meiosis-Specific Ime2 Protein Kinase in Saccharomyces cerevisiae

• Published in: Biochemistry (Easton) Vol. 46; no. 1; pp. 271 - 278
• Main Authors: Moore, Michael, Shin, Marcus E, Bruning, Adrian, Schindler, Karen, Vershon, Andrew, Winter, Edward
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 09.01.2007
• Subjects: Amino Acid Motifs; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Intracellular Signaling Peptides and Proteins; Meiosis; Nuclear Proteins - chemistry; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Phosphorylation; Protein Kinases - genetics; Protein Kinases - metabolism; Protein Phosphatase 1; Protein-Serine-Threonine Kinases; RecQ Helicases - genetics; RecQ Helicases - metabolism; Repressor Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Threonine - analysis; Threonine - metabolism; Transcription, Genetic
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi061858p

Ime2 is a meiosis-specific protein kinase in Saccharomyces cerevisiae that is functionally related to cyclin-dependent kinase. Although Ime2 regulates multiple steps in meiosis, only a few of its substrates have been identified. Here we show that Ime2 phosphorylates Sum1, a repressor of meiotic gene transcription, on Thr-306. Ime2 protein kinase assays with Sum1 mutants and synthetic peptides define a consensus Arg-Pro-X-Ser/Thr motif that is required for efficient phosphorylation by Ime2. The carboxyl residue adjacent to the phosphoacceptor (+1 position) also influences the efficiency of Ime2 phosphorylation with alanine being a preferred residue. This information has predictive value in identifying new potential Ime2 targets as shown by the ability of Ime2 to phosphorylate Sgs1 and Gip1 in vitro and could be important in differentiating mitotic and meiotic regulatory pathways.