Asymmetric microtubule pushing forces in nuclear centering
Asymmetric microtubule pushing forces in nuclear centering
复制标题
DOI：
10.1016/j.cub.2006.06.026
复制
发表时间：
2006-08-08
期刊：
影响因子：
9.2
通讯作者：
Chang, Fred
中科院分区：
文献类型：
--
作者：
Daga, Rafael R.;Yonetani, Ann;Chang, Fred
微管的动态特性有助于细胞内空间秩序的建立。在裂殖酵母裂殖酵母中，间期细胞质微管被组织成附着在核膜上的反平行束，并且需要将细胞核定位在细胞的几何中心[1，2]。在这里，我们表明，细胞核被细胞离心移位后，这些微管束有效地将细胞核推回中心。微管数量、长度和动力学的不对称性有助于产生负责这种单向运动的力。值得注意的是，当同一束中的微管从近端细胞尖端推动时，面向远端细胞尖端的微管不稳定。CLIP-170样蛋白tip 1 p [3]和微管束蛋白酶1 p [4，5]是微管动力学的这种不对称调节所必需的，表明微管加端和微管束内的因子都有贡献。这些因子中的突变体在核运动中有缺陷。因此，细胞拥有一个有效的基于微管的引擎，可以产生和感知使细胞核居中的力。这些研究可能提供洞察机制的不对称微管行为和力传感在其他过程中，如染色体分离和细胞极化。
Dynamic properties of microtubules contribute to the establishment of spatial order within cells. In the fission yeast Schizosaccharomyces pombe, interphase cytoplasmic microtubules are organized into antiparallel bundles that attach to the nuclear envelope and are needed to position the nucleus at the geometric center of the cell [1, 2]. Here, we show that after the nucleus is displaced by cell centrifugation, these microtubule bundles efficiently push the nucleus back to the center. Asymmetry in microtubule number, length, and dynamics contributes to the generation of force responsible for this unidirectional movement. Notably, microtubules facing the distal cell tip are destabilized when the microtubules in the same bundle are pushing from the proximal cell tip. The CLIP-170-like protein tip1p [3] and the microtubule-bundling proteinase1p [4,5] are required for this asymmetric regulation of microtubule dynamics, indicating contributions of factors both at microtubule plus ends and within the microtubule bundle. Mutants in these factors are defective in nuclear movement. Thus, cells possess an efficient microtubule-based engine that produces and senses forces for centering the nucleus. These studies may provide insights into mechanisms of asymmetric microtubule behaviors and force sensing in other processes such as chromosome segregation and cell polarization.