||Phosphoproteomic analysis of human mitotic chromosomes identified a chromokinesin KIF4A.
Takahashi, Motoko髙橋, 元子
17 , 2016-03-23 , 新潟大学
学位の種類: 博士（医学）. 報告番号: 甲第4115号. 学位記番号: 新大院博（医）甲第682号. 学位授与年月日: 平成28年3月23日
Biomedical Research. 2016, 37(2), 161-165.
Protein phosphorylation is the prime post-translational modification to drive cell division. Identification of phosphorylated proteins and their related kinases has uncovered molecular networks underlying mitotic processes, including chromosome assembly. Here we aimed to identify phosphoproteins from a mitotic chromosome-enriched lysate biochemically using mass spectrometry. We employed the Polo-box domain (PBD) of Polo-like kinase to tether phosphorylated proteins in the lysate. Resulting candidates included a number of chromosomal proteins that would not be identified unless using chromosome-enriched fractions. Among them, we focused to a chromokinesin KIF4A which becomes concentrated along the longitudinal axis of mitotic condensed chromatids. We found that KIF4A is phosphorylated specifically during mitosis, depending on the activity of Cdk1 and Aurora B, which turned out to be required for KIF4A to interact with condensin I. The molecular link between KIF4A and condensin raises an interesting possibility that the interaction of two distantly related ATPases is triggered by mitotic phosphorylation.