Division of Molecular Pathophysiology, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria.
Mol Biol Cell. 2010 Jun 15;21(12):1968-81. doi: 10.1091/mbc.e09-04-0356. Epub 2010 Apr 28.
Spindly recruits a fraction of cytoplasmic dynein to kinetochores for poleward movement of chromosomes and control of mitotic checkpoint signaling. Here we show that human Spindly is a cell cycle-regulated mitotic phosphoprotein that interacts with the Rod/ZW10/Zwilch (RZZ) complex. The kinetochore levels of Spindly are regulated by microtubule attachment and biorientation induced tension. Deletion mutants lacking the N-terminal half of the protein (NDelta253), or the conserved Spindly box (DeltaSB), strongly localized to kinetochores and failed to respond to attachment or tension. In addition, these mutants prevented the removal of the RZZ complex and that of MAD2 from bioriented chromosomes and caused cells to arrest at metaphase, showing that RZZ-Spindly has to be removed from kinetochores to terminate mitotic checkpoint signaling. Depletion of Spindly by RNAi, however, caused cells to arrest in prometaphase because of a delay in microtubule attachment. Surprisingly, this defect was alleviated by codepletion of ZW10. Thus, Spindly is not only required for kinetochore localization of dynein but is a functional component of a mechanism that couples dynein-dependent poleward movement of chromosomes to their efficient attachment to microtubules.
Spindly 将细胞质动力蛋白的一小部分招募到动粒，以实现染色体向极的运动和有丝分裂检查点信号的控制。在这里，我们表明人类 Spindly 是一种细胞周期调节的有丝分裂磷酸蛋白，它与 Rod/ZW10/Zwilch (RZZ) 复合物相互作用。Spindly 的动粒水平受到微管附着和双取向诱导张力的调节。缺失蛋白 N 端一半（NDelta253）或保守的 Spindly 盒（DeltaSB）的缺失突变体强烈定位于动粒，并且无法响应附着或张力。此外，这些突变体阻止了 RZZ 复合物和 MAD2 从双取向染色体上的去除，并导致细胞在中期停滞，表明 RZZ-Spindly 必须从动粒上去除才能终止有丝分裂检查点信号。然而，通过 RNAi 耗尽 Spindly 会导致细胞因微管附着延迟而在前期停滞。令人惊讶的是，这一缺陷可以通过 ZW10 的共缺失得到缓解。因此，Spindly 不仅是动力蛋白向动粒定位所必需的，而且是一种将染色体依赖动力蛋白的向极运动与它们与微管的有效附着相偶联的机制的功能组成部分。
