Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea.
J Biol Chem. 2010 Aug 13;285(33):25476-84. doi: 10.1074/jbc.M109.099127. Epub 2010 May 29.
Centrobin/NIP2 is a centrosomal protein that is required for centrosome duplication. It is also critical for microtubule organization in both interphase and mitotic cells. In the present study, we observed that centrobin is phosphorylated in a cell cycle stage-specific manner, reaching its maximum at M phase. PLK1 is a kinase that is responsible for M phase-specific phosphorylation of centrobin. The microtubule forming activity of centrobin was enhanced by PLK1 phosphorylation. Furthermore, mitotic spindles were not assembled properly with the phospho-resistant mutant of centrobin. Based on these results, we propose that centrobin functions as a microtubule stabilizing factor and PLK1 enhances centrobin activity for proper spindle formation during mitosis.
中心体蛋白 NIP2(Centrobin/NIP2)是一种与中心体复制相关的蛋白,它对于间期和有丝分裂细胞中的微管组织也非常重要。在本研究中,我们观察到中心体蛋白在细胞周期中以阶段特异性的方式发生磷酸化,在 M 期达到最大值。PLK1 是一种激酶,负责中心体蛋白的 M 期特异性磷酸化。PLK1 磷酸化增强了中心体蛋白的微管形成活性。此外,带有磷酸化抗性突变的中心体蛋白组装的有丝分裂纺锤体不正常。基于这些结果,我们提出中心体蛋白作为微管稳定因子发挥功能,PLK1 增强中心体蛋白的活性,以在有丝分裂过程中正确形成纺锤体。