Mollinari Cristiana, Reynaud Caroline, Martineau-Thuillier Stephanie, Monier Solange, Kieffer Sylvie, Garin Jerome, Andreassen Paul R, Boulet Annick, Goud Bruno, Kleman Jean-Philippe, Margolis Robert L
Institut de Biologie Structurale J-P Ebel, CEA-CNRS, 41 rue Jules Horowitz, 38027 Cedex 1, Grenoble, France.
Dev Cell. 2003 Aug;5(2):295-307. doi: 10.1016/s1534-5807(03)00205-3.
Passenger proteins migrate from inner centromeres to the spindle midzone during late mitosis, and those described to date are essential both for proper chromosome segregation and for completion of cell cleavage. We have purified and cloned the human passenger protein TD-60, and we here report that it is a member of the RCC1 family and that it binds preferentially the nucleotide-free form of the small G protein Rac1. Using siRNA, we further demonstrate that the absence of TD-60 substantially suppresses overall spindle assembly, blocks cells in prometaphase, and activates the spindle assembly checkpoint. These defects suggest TD-60 may have a role in global spindle assembly or may be specifically required to integrate kinetochores into the mitotic spindle. The latter is consistent with a TD-60 requirement for recruitment of the passenger proteins survivin and Aurora B, and suggests that like other passenger proteins, TD-60 is involved in regulation of cell cleavage.
在有丝分裂后期，乘客蛋白从内着丝粒迁移至纺锤体中区，迄今为止所描述的这些蛋白对于正确的染色体分离以及细胞分裂的完成均至关重要。我们已经纯化并克隆了人类乘客蛋白TD-60，在此报告它是RCC1家族的一员，并且它优先结合小G蛋白Rac1的无核苷酸形式。利用小干扰RNA，我们进一步证明TD-60的缺失会显著抑制纺锤体的整体组装，使细胞阻滞在前中期，并激活纺锤体组装检验点。这些缺陷表明TD-60可能在整体纺锤体组装中发挥作用，或者可能是将动粒整合到有丝分裂纺锤体中所特别需要的。后者与招募乘客蛋白生存素和极光激酶B对TD-60的需求相一致，并表明与其他乘客蛋白一样，TD-60参与细胞分裂的调控。
