Mitotic phosphorylation of PRC1 at Thr470 is required for PRC1 oligomerization and proper central spindle organization  

作　　者：Chuanhai Fu Feng Yan Fang Wu Quan Wu Joseph Whittaker Haiying Hu Renming Hu Xuebiao Yao 

机构地区：[1]Laboratory of Cellular Dynamics, Hefei National Laboratory and the University of Science and Technology of China, Hefei 230027, China, [2]Department of Physiology Atlanta, GA 30310, USA, [3]Department of Anatomy & Neurobiology, Morehouse School of Medicine, Atlanta, GA 30310, USA, [4]Department of Endocrinology, Huashan Hospital, Fudan University School of Medicine, Shanghai 200040, China

出　　处：《Cell Research》2007年第5期449-457,共9页细胞研究（英文版）

基　　金：National Natural Science Foundation of China （39925018, 90508002 , 30121001）; Chinese Academy of Science （KSCX 1-R65 and RSCX2-H10）; National Basic Research Program of China （973 project, 2002CB713700）; American Cancer Society （RPG-99-173-01）; a Gcc Breast Cancer Research award and National Institutes of Health grants DK56292 and CA89019 to XY （a GCC Eminent Scholar） and NS36194 （JW）.

摘　　要：During cell division, chromosome segregation is orchestrated by the interaction of spindle microtubules with the centromere. A dramatic remodeling of interpolar microtubules into an organized central spindle between the separating chromatids is required for the initiation and execution ofcytokinesis. Central spindle organization requires mitotic kinesins, the chromosomal passenger protein complex, and microtubule bundling protein PRC 1. PRC 1 is phosphorylated by Cdc2 at Thr470 and Thr481 during mitosis. However, the functional relevance of PRC 1 phosphorylation at Thr470 has remained elusive. Here we show that expression of the non-phosphorylatable mutant PRC 1T470A but not the phospho-mimicking mutant PRC 1^T470E causes aberrant organization of the central spindle. Immunoprecipitation experiment indicates that both PRC 1^T470A and PRC 1^T470E mutant proteins associate with wild-type PRC 1, suggesting that phosphorylation of Thr470 does not alter PRC 1 self-association. In addition, in vitro co-sedimentation experiment showed that PRC 1 binds to microtubule independent of the phosphorylation state of Thr470. Gel-filtration experiment suggested that phosphorylation of Thr470 promotes oligomerization of PRC 1. Given the fact that prevention of the Thr470 phosphorylation inhibits PRC 1 oligomerization in vitro and causes an aberrant organization of central spindle in vivo, we propose that this phosphorylation-dependent PRC 1 oligomerization ensures that central spindle assembly occurs at the appropriate time in the cell cycle.

关 键 词：central spindle MICROTUBULE OLIGOMERIZATION PRC 1 PHOSPHORYLATION 

分 类 号：Q253[生物学—细胞生物学] Q26