title: Fission yeast LAMMER kinase Lkh1 regulates the cell cycle by phosphorylating the CDK-inhibitor Rum1.
abstract: In eukaryotes, LAMMER kinases are involved in various cellular events, including the cell cycle. However, no attempt has been made to investigate the mechanisms that underlie the involvement of LAMMER kinase. In this study, we performed a functional analysis of LAMMER kinase using the fission yeast, Schizosaccharomyces pombe. FACS analyses revealed that deletion of the gene that encodes the LAMMER kinase Lkh1 made mutant cells pass through the G1/S phase faster than their wild-type counterparts. Co-immunoprecipitation and an in vitro kinase assay also revealed that Lkh1 can interact with and phosphorylate Rum1 to activate this molecule as a cyclin-dependent kinase inhibitor, which blocks cell cycle progression from the G1 phase to the S phase. Peptide mass fingerprinting and kinase assay with Rum1(T110A) confirmed T110 as the Lkh1-dependent phosphorylation residue. In this report we present for the first time a positive acting mechanism that is responsible for the CKI activity of Rum1, in which the LAMMER kinase-mediated phosphorylation of Rum1 is involved.
authors: Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764, Republic of Korea.
authors: Eun-Young
authors: EY
authors: Yu
authors: Ju-Hee
authors: JH
authors: Lee
authors: Won-Hwa
authors: WH
authors: Kang
authors: Yun-Hee
authors: YH
authors: Park
authors: Lila
authors: L
authors: Kim
authors: Hee-Moon
authors: HM
authors: Park
mesh_terms: D002453:Cell Cycle / Q000235:genetics*; D002469:Cell Separation; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D005434:Flow Cytometry; D059585:G1 Phase Cell Cycle Checkpoints / Q000235:genetics; D017353:Gene Deletion; D009584:Nitrogen / Q000172:deficiency; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000166:cytology* / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C086077:Rum1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D011494:Protein Kinases; C446922:lkh1 protein, S pombe; D018844:Cyclin-Dependent Kinases; D009584:Nitrogen