SENP3调控Aurora-A的SUMO化修饰对氧化应激下分裂期细胞纺锤体结构的影响

Mild oxidative stress can cause abnormal structure and function in cell division, especially the abnormal structure and function of the important mitotic device spindle. The underlying molecular mechanisms for the abnormal structures are uncovered. Although earlier study showed that Aurora-A play crucial roles in maintaining spindle structure and function, so far the regulating mechanism including possible substrates and interacting proteins are all not clear. The results of our group in recent years have shown that mild oxidative stress can cause SUMO protease SENP3 protein accumulation and its sub-localization alteration among non-mitotic cells. Our previous results gave us hints that mild oxidative stress caused the spindle shrunk; at the same time, the accumulated SENP3 protein resulting from mild oxidative stress sub-localized at the centrosome and bipolar spindles; in addition, SENP3 affected the Aurora-A SUMOylation. This project aims at the investigation that 1) whether SUMO2/3 specific protease SENP3 which accumulate and sub-localize at the centrosome and bipolar spindles in mitotic cells under mild oxidative stress involve in or account for the abnormal spindle structure and function under mild oxidative stress; 2）whether and how SENP3 mediate Aurora-A SUMOylation and impact its auto-phosphorylation and ultimately cause the abnormal spindle structure and function. We purpose to throw light on the role of SENP3 in mitotic cell under oxidative stress.

轻度氧化应激造成细胞分裂期异常、尤其是分裂期重要装置纺锤体结构、功能异常的分子机制研究很少。虽然早期研究显示：Aurora-A对纺锤体结构功能的维持至关重要，但迄今为止其调控机制包括其自身的翻译后修饰、可能底物和相互作用蛋白都不清楚。本课题组近年研究显示：轻度氧化应激造成SUMO蛋白酶SENP3蛋白的累积和其在间期细胞中定位的改变。最近，本项目预初结果提示：轻度氧化应激造成纺锤体塌陷；同时累积的SENP3聚集在纺锤体两极；SENP3影响了Aurora-A的SUMO化修饰。本项目拟考察氧化应激下1）SENP3在分裂期细胞中是否参与或负责应激造成的纺锤体结构、功能异常；2）SENP3是否及如何介导Aurora-A的SUMOylation修饰影响其自身磷酸化修饰并最终造成应激引起的纺锤体结构、功能异常，以期阐明SENP3在分裂期细胞氧化应激中的角色。

轻度氧化应激能引起SUMO 蛋白酶 SENP3蛋白累积，同时造成细胞分裂期异常，但SENP3对分裂期细胞的调控尤其是分裂期重要装置纺锤体结构、功能异常的分子机制研究很少。早期研究显示：Aurora-A 对纺锤体结构功能的维持至关重要，但迄今为止其调控机制包括其自身的翻译后修饰、可能底物和相互作用蛋白都不清楚。. 本研究发现外源或内源SENP3蛋白在有丝分裂细胞的纺锤体上聚集、定位；提出Aurora-A的自磷酸化及活性减少依赖其SUMO修饰，且SENP3 通过影响 Aurora-A 的去SUMO化修饰来调控Aurora-A 的磷酸化修饰并进而影响了Aurora-A的蛋白活性；首次提出定位在纺锤体的SENP3蛋白通过影响Aurora-A的蛋白活性从而延迟了纺锤体的装配和染色体的列队最终阻止了分裂期细胞向各期推进即影响了细胞分裂周期进程；对氧化应激敏感的蛋白酶SENP3影响的蛋白质去SUMO化修饰是调控细胞分裂装置及细胞周期进程的一种重要翻译后修饰。. 本研究的意义在于首次揭示了纺锤体定位的SENP3蛋白通过影响Aurora-A的蛋白活性延迟了纺锤体的装配和染色体的列队最终阻止了细胞分裂周期进程；发现SENP3调控的SUMO化修饰是除磷酸化修饰和泛素化修饰以外的另一种调控细胞分裂装置及细胞周期进程的重要翻译后修饰。