Université de Paris, CNRS, Institut Jacques Monod, 15 rue Hélène Brion, Paris, 75013, France.
Biol Cell. 2020 Oct;112(10):300-315. doi: 10.1111/boc.201900105. Epub 2020 Jul 20.
The RZZ complex, composed of the proteins Rough-Deal (Rod), Zw10 and Zwilch, plays a central role in the spindle assembly checkpoint (SAC), which assures proper sister chromatid segregation during mitosis. RZZ contributes to the regulation of the spindle assembly checkpoint by helping to recruit Mad1-Mad2 and the microtubule motor dynein to unattached kinetochores. It is an important component of the outer kinetochore and specifically the fibrous corona whose expansion is believed to facilitate microtubule capture. How RZZ carries out its diverse activities is only poorly understood. The C-terminal region of the Rod subunit is relatively well-conserved across metazoan phylogeny, but no function has been attributed to it.
To explore the importance of the Rod_C domain in RZZ function in Drosophila, we generated a series of point mutations in a stretch of 200 residues within this domain and we report here their phenotypes. Several of the mutations profoundly disrupt recruitment of RZZ to kinetochores, including one in a temperature-sensitive manner, while still retaining the capacity to assemble into a complex with Zw10 and Zwilch. Others affect aspects of dynein activity or recruitment at the kinetochore.
These results suggest that the Rod_C domain participates in the protein interactions necessary for RZZ recruitment and functionality at kinetochores.
RZZ 复合物由蛋白质 Rough-Deal（Rod）、Zw10 和 Zwilch 组成，在纺锤体组装检查点（SAC）中发挥核心作用，该检查点可确保有丝分裂期间姐妹染色单体的正确分离。RZZ 通过帮助募集 Mad1-Mad2 和微管动力蛋白 dynein 到未连接的动粒，有助于调节纺锤体组装检查点。它是外动粒的重要组成部分，特别是纤维冠状结构，其扩展被认为有助于微管捕获。RZZ 如何执行其多种活性还知之甚少。Rod 亚基的 C 末端区域在后生动物的系统发育中相对保守，但尚未赋予其功能。
为了探究 Rod_C 结构域在果蝇 RZZ 功能中的重要性，我们在该结构域内的 200 个残基长的一段序列中生成了一系列点突变，并在此报告其表型。该突变严重破坏了 RZZ 向动粒的募集，包括以温度敏感的方式募集，同时仍保留与 Zw10 和 Zwilch 组装成复合物的能力。其他突变则影响动粒处 dynein 活性或募集的各个方面。
这些结果表明，Rod_C 结构域参与了 RZZ 在动粒处募集和功能所需的蛋白相互作用。
