激活转录因子5的类泛素化（SUMO）修饰调控中心粒外周物质动态组装的分子机制研究

中心体是哺乳动物细胞内的微管组织中心，中心粒外周物质（PCM）是发挥微管组织功能的基本结构。PCM组装异常会引起中心体功能紊乱，影响正常的细胞分裂和诱发多种人类疾病。申请人发现激活转录因子5（ATF5）是中心体调控蛋白之一，它分别通过与中心粒三联微管上的聚谷氨酸酰化微管蛋白（PGT）结合和与PCM骨架蛋白中心粒旁素（PCNT）相互作用调控PCNT在中心粒上的组装。申请人最新研究发现，ATF5的类泛素化（SUMO）修饰具有细胞周期依赖性，且抑制ATF5在中心体上的定位。据此申请人提出ATF5的SUMO修饰抑制PCNT-ATF5-PGT复合物形成并调控中心体PCM动态组装的假设。本项目将运用定量蛋白质组学、基因干扰、活细胞延时观察（Time-Lapse）以及中心体体外结合分析等技术研究ATF5的SUMO修饰和去SUMO修饰对中心体PCM动态组装的影响以及其在中心体功能调控方面的生物学意义

Centrosome is the primary microtubule-organizing center in the mammalian cells and the surrounding pericentriolar material (PCM) plays a critical role in microtubules (MTs) nucleation at the centrosome. Abnormal PCM assembling will result in deficiency of centrosome function and induce many human diseases. We found that activating transcription factor 5(ATF5) was one of centrosomal proteins and regulated PCM assembly through associating with polyglutamylated tubulin (PGT) and pericentrin (PCNT). Recently, we found ATF5 sumoylation was dependent on cell cycle and sumoylation of ATF5 decreased ATF5 accumulation on centrosome. In conclusion, we propose that ATF5 sumoylation interferes in formation of PCNT-ATF5-PGT complex and regulates dynamic assembly of PCM at the centrosome. For investigating effects of ATF5 sumo- or desumoylation on centrosome biological functions and PCM assembly, several advanced techniques will be used in this proposed study. These techniques include quantitative proteomic, genes interference, Time-Lapse microscope and centrosome binding assay, etc. The proposed study may not only bring new insight into understanding mechanism of ATF5 sumoylation regulating PCM dynamic assembly and promoting progress in the centrosome biology, but also provide new concepts and new candidate targets for curing deficiency of PCM functions related diseases in human.