摘要
在细胞分裂期间，染色体分离被和着丝点的锭子微导管的相互作用安排。进在分开的染色单体之间的一支组织中央锭子的 interpolarmicrotubules 的戏剧的改变为胞质分裂的开始和实行被要求。中央锭子组织要求有丝分裂的 kinesins， chromosomal 旅客蛋白质建筑群，和微导管捆绑蛋白质 PRC1。由在 Thr470 和 Thr481 的 Cdc2 的 PRC1 isphosphorylated 在有丝分裂期间。然而，在 Thr470 的功能的关联 ofPRC1 磷酸化留下了逃犯。这里，我们证明 thenon-phosphorylatable 异种 PRC1 (T470A ) 然而并非 phospho-mimicking 异种 PRC1 (T470E ) 的那表情引起中央锭子的异常组织。Immunoprecipitation 实验与野类型的 PRC1 显示那 bothPRC1 (T470A ) 和 PRC1 (T470E ) 突变蛋白质伙伴，建议 Thr470 的 thatphosphorylation 不改变 PRC1 自我协会。另外，在 vitroco 沉积，实验证明 PRC1 绑在独立于 Thr470 的 phosphorylationstate 的微导管。胶化过滤实验建议了 PRC1 的 Thr470 promotesoligomerization 的那磷酸化。给 Thr470 磷酸化的那预防禁止 PRC1oligomerization 试管内并且引起中央锭子体内的一个异常组织的事实，我们建议这 phosphorylation 依赖的 PRC1 oligomerization 保证中央锭子汇编在房间周期发生在适当时间。
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.
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）.
