PNAS:两种截然不同的推动锥虫细胞从相反的细胞两端起始分裂的
2016年3月22日，国际著名学术期刊《美国国家科学院院刊》杂志在线发表了德克萨斯大学医学院微生物学与分子遗传学教研室Ziyin Li研究组题为Two distinct cytokinesis pathways drive trypanosome cell division initiation from opposite cell ends的研究论文。
研究论文揭示了CIF1和Polo样激酶启动胞质分裂的作用机理并阐明了在细胞分裂晚后期Aurora B激酶招募到胞质分裂起始位点的潜在机制。德克萨斯大学的Qing Zhou为第一作者，德克萨斯大学的Ziyin Li和加利福尼亚大学的Francisco J. Ayala为共同通讯作者。
早期分支原生动物布氏锥虫的胞质分裂是从新鞭毛连接区长丝的前尖沿其纵轴朝细胞后末端单向发生。然而，其潜在的作用机制却不清楚。
在本项研究中，Ziyin Li研究组的学生Qing Zhou等证明了布氏锥虫胞质分裂由Polo样激酶，Aurora B激酶，和锥虫特异蛋白CIF1共同作用下调节的。被Polo样激酶磷酸化的CIF1的靶向新鞭毛附着区纤维的前端，它随后招募Aurora B激酶启动胞质分裂。与CIF1的作用一致的是，CIF1的耗尽抑制胞质从细胞的前端启动分裂，但令人惊讶的却是会激发胞质分裂从细胞的后端启动，这表明激活了一个可替代的胞质从相反细胞末端分裂的途径。该研究结果揭示了CIF1和Polo样激酶启动胞质分裂的作用机理并阐明了在细胞分裂晚后期Aurora B激酶招募到胞质分裂起始位点的潜在机制。这些研究结果也显示了信号级联控制的细胞分裂起始于细胞的前端，揭露了当典型的从前端到后端胞质分裂受阻时存在一个可替代的从细胞后端启动胞质分裂的途径。
原文链接：
Two distinct cytokinesis pathways drive trypanosome cell division initiation from opposite cell ends
原文摘要：
Cytokinesis in Trypanosoma brucei, an early branching protozoan, occurs along its longitudinal axis uni-directionally from the anterior tip of the new flagellum attachment zone filament toward the Cell’s posterior end. However, the underlying mechanisms remain elusive. Here we report that cytokinesis in T. brucei is regulated by a concerted action of Polo-like kinase, Aurora B kinase, and a trypanosome-specific protein CIF1. Phosphorylation of CIF1 by Polo-like kinase targets it to the anterior tip of the new flagellum attachment zone filament, where it subsequently recruits Aurora B kinase to initiate cytokinesis. Consistent with its role, CIF1 depletion inhibits cytokinesis initiation from the anterior end of the cell, but, surprisingly, triggers cytokinesis initiation from the posterior end of the cell, suggesting the activation of an alternative cytokinesis from the opposite cell end. Our results reveal the mechanistic roles of CIF1 and Polo-like kinase in cytokinesis initiation and elucidate the mechanism underlying the recruitment of Aurora B kinase to the cytokinesis initiation site at late anaphase. These findings also delineate a signaling cascade controlling cytokinesis initiation from the anterior end of the cell and uncover a backup cytokinesis that is initiated from the posterior end of the cell when the typical anterior-to-posterior cytokinesis is compromised.
作者：生物帮
