Wang Y X, Zhao H, Harding T M, Gomes de Mesquita D S, Woldringh C L, Klionsky D J, Munn A L, Weisman L S
Department of Biochemistry, University of Iowa, Iowa City 52242, USA.
Mol Biol Cell. 1996 Sep;7(9):1375-89. doi: 10.1091/mbc.7.9.1375.
In Saccharomyces cerevisiae the vacuoles are partitioned from mother cells to daughter cells in a cell-cycle-coordinated process. The molecular basis of this event remains obscure. To date, few yeast mutants had been identified that are defective in vacuole partitioning (vac), and most such mutants are also defective in vacuole protein sorting (vps) from the Golgi to the vacuole. Both the vps mutants and previously identified non-vps vac mutants display an altered vacuolar morphology. Here, we report a new method to monitor vacuole inheritance and the isolation of six new non-vps vac mutants. They define five complementation groups (VAC8-VAC12). Unlike mutants identified previously, three of the complementation groups exhibit normal vacuolar morphology. Zygote studies revealed that these vac mutants are also defective in intervacuole communication. Although at least four pathways of protein delivery to the vacuole are known, only the Vps pathway seems to significantly overlap with vacuole partitioning. Mutants defective in both vacuole partitioning and endocytosis or vacuole partitioning and autophagy were not observed. However, one of the new vac mutants was additionally defective in direct protein transport from the cytoplasm to the vacuole.
在酿酒酵母中，液泡通过细胞周期协调的过程从母细胞分配到子细胞。这一事件的分子基础仍不清楚。迄今为止，很少有被鉴定出的酵母突变体在液泡分配（vac）方面存在缺陷，并且大多数此类突变体在从高尔基体到液泡的液泡蛋白分选（vps）方面也存在缺陷。vps突变体和先前鉴定的非vps vac突变体均表现出液泡形态的改变。在此，我们报告一种监测液泡遗传的新方法以及六个新的非vps vac突变体的分离。它们定义了五个互补群（VAC8 - VAC12）。与先前鉴定的突变体不同，其中三个互补群表现出正常的液泡形态。合子研究表明，这些vac突变体在液泡间通讯方面也存在缺陷。尽管已知至少有四条蛋白质输送到液泡的途径，但似乎只有Vps途径与液泡分配有显著重叠。未观察到在液泡分配和内吞作用或液泡分配和自噬方面均存在缺陷的突变体。然而，其中一个新的vac突变体在从细胞质到液泡的直接蛋白质运输方面还存在额外缺陷。
