The role of the lissencephaly protein Pac1 during nuclear migration in budding yeast.
The role of the lissencephaly protein Pac1 during nuclear migration in budding yeast.
复制标题
DOI：
10.1083/jcb.200209022
复制
发表时间：
2003-02-03
影响因子：
7.8
通讯作者：
Cooper, John A
中科院分区：
文献类型：
--
作者：
Lee, Wei-Lih;Oberle, Jessica R;Cooper, John A
在酿酒酵母有丝分裂过程中，有丝分裂纺锤体通过依赖于动力蛋白的细胞质微管沿着芽的皮层滑动进入母芽颈。在这里，我们证明了Pac1，人类无脑蛋白Lis1的酵母同源物，在这一过程中发挥了关键作用。首先，遗传交互作用将Pac1置于dynein/dynactin途径。第二，缺乏Pac1的细胞不能在芽中显示微管滑动，导致有丝分裂纺锤体运动缺陷和核分离。第三，Pac1定位于芽中细胞质微管的正端(远端)。这种定位不依赖于动力蛋白重链Dy1。此外，在缺乏dynactin或皮质附着分子Num1的细胞中，微管末端的Pac1荧光强度增强。第四，在野生型细胞中，动力蛋白重链Dy1也定位于细胞质微管的顶端。动力蛋白的定位需要Pac1，和Pac1一样，在缺乏动力蛋白成分Arp1或皮质附着分子Num1的细胞中，动力蛋白定位得到增强。我们的结果表明，Pac1将dynein定位于微管尖端，这是微管沿芽皮质滑动所必需的。动力蛋白必须保持不活跃，直到微管末端与芽皮质相互作用，此时动力蛋白和Pac1似乎从微管卸载到皮质。
During mitosis in Saccharomyces cerevisiae, the mitotic spindle moves into the mother–bud neck via dynein-dependent sliding of cytoplasmic microtubules along the cortex of the bud. Here we show that Pac1, the yeast homologue of the human lissencephaly protein LIS1, plays a key role in this process. First, genetic interactions placed Pac1 in the dynein/dynactin pathway. Second, cells lacking Pac1 failed to display microtubule sliding in the bud, resulting in defective mitotic spindle movement and nuclear segregation. Third, Pac1 localized to the plus ends (distal tips) of cytoplasmic microtubules in the bud. This localization did not depend on the dynein heavy chain Dyn1. Moreover, the Pac1 fluorescence intensity at the microtubule end was enhanced in cells lacking dynactin or the cortical attachment molecule Num1. Fourth, dynein heavy chain Dyn1 also localized to the tips of cytoplasmic microtubules in wild-type cells. Dynein localization required Pac1 and, like Pac1, was enhanced in cells lacking the dynactin component Arp1 or the cortical attachment molecule Num1. Our results suggest that Pac1 targets dynein to microtubule tips, which is necessary for sliding of microtubules along the bud cortex. Dynein must remain inactive until microtubule ends interact with the bud cortex, at which time dynein and Pac1 appear to be offloaded from the microtubule to the cortex.