Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764, Republic of Korea.
Biochem Biophys Res Commun. 2013 Mar 1;432(1):80-5. doi: 10.1016/j.bbrc.2013.01.082. Epub 2013 Jan 29.
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.
在真核生物中，LAMMER 激酶参与多种细胞事件，包括细胞周期。然而，尚未尝试研究 LAMMER 激酶参与的机制。在这项研究中，我们使用裂殖酵母 Schizosaccharomyces pombe 对 LAMMER 激酶进行了功能分析。FACS 分析显示，缺失编码 LAMMER 激酶 Lkh1 的基因的突变细胞比其野生型细胞更快地通过 G1/S 期。共免疫沉淀和体外激酶测定还表明，Lkh1 可以与 Rum1 相互作用并磷酸化它，从而激活作为细胞周期蛋白依赖性激酶抑制剂的该分子，该抑制剂阻止细胞周期从 G1 期向 S 期的进展。肽质量指纹图谱分析和 Rum1(T110A)的激酶测定证实 T110 是 Lkh1 依赖性磷酸化残基。在本报告中，我们首次提出了一种负责 Rum1 的 CKI 活性的正向作用机制，其中涉及 LAMMER 激酶介导的 Rum1 磷酸化。
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