University of Colorado Anschutz Medical Campus, Department of Biochemistry and Molecular Genetics, 12801 East 17th Avenue, Aurora, Colorado 80045, USA; Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
University of Colorado Anschutz Medical Campus, Department of Biochemistry and Molecular Genetics, 12801 East 17th Avenue, Aurora, Colorado 80045, USA; Anderson University, Department of Chemistry and Biology, 316 Boulevard, Anderson, SC 29621, USA.
J Mol Biol. 2021 Feb 19;433(4):166812. doi: 10.1016/j.jmb.2021.166812. Epub 2021 Jan 13.
Spindly is a dynein adaptor involved in chromosomal segregation during cell division. While Spindly's N-terminal domain binds to the microtubule motor dynein and its activator dynactin, the C-terminal domain (Spindly-C) binds its cargo, the ROD/ZW10/ZWILCH (RZZ) complex in the outermost layer of the kinetochore. In humans, Spindly-C binds to ROD, while in C. elegans Spindly-C binds to both Zwilch (ZWL-1) and ROD-1. Here, we employed various biophysical techniques to characterize the structure, dynamics and interaction sites of C. elegans Spindly-C. We found that despite the overall disorder, there are two regions with variable α-helical propensity. One of these regions is located in the C-terminal half and is compact; the second is sparsely populated in the N-terminal half. The interactions with both ROD-1 and ZWL-1 are mostly mediated by the same two sequentially remote disordered segments of Spindly-C, which are C-terminally adjacent to the helical regions. The findings suggest that the Spindly-C binding sites on ROD-1 in the ROD-1/ZWL-1 complex context are either shielded or conformationally weakened by the presence of ZWL-1 such that only ZWL-1 directly interacts with Spindly-C in C. elegans.
Spindly 是一种参与细胞分裂过程中染色体分离的动力蛋白衔接物。Spindly 的 N 端结构域与微管动力蛋白 dynein 及其激活因子 dynactin 结合，而 C 端结构域（Spindly-C）与它的货物结合，即动粒最外层的 ROD/ZW10/ZWILCH（RZZ）复合物。在人类中，Spindly-C 与 ROD 结合，而在秀丽隐杆线虫中，Spindly-C 与 Zwilch（ZWL-1）和 ROD-1 都结合。在这里，我们采用了各种生物物理技术来表征秀丽隐杆线虫 Spindly-C 的结构、动力学和相互作用位点。我们发现，尽管整体无序，但有两个区域具有可变的α-螺旋倾向。其中一个区域位于 C 端的一半，结构紧凑；另一个区域在 N 端的一半稀疏存在。与 ROD-1 和 ZWL-1 的相互作用主要由 Spindly-C 的两个连续的远程无序片段介导，这两个片段与螺旋区域在 C 端相邻。这些发现表明，在 ROD-1/ZWL-1 复合物的背景下，ROD-1 上的 Spindly-C 结合位点要么被 ZWL-1 屏蔽，要么被其构象弱化，使得只有 ZWL-1 直接与秀丽隐杆线虫中的 Spindly-C 相互作用。
