Vac7p, a novel vacuolar protein, is required for normal vacuole inheritance and morphology
Vac7p, a novel vacuolar protein, is required for normal vacuole inheritance and morphology
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DOI：
10.1128/mcb.17.12.6847
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发表时间：
1997-12-01
影响因子：
5.3
通讯作者：
Weisman, LS
中科院分区：
文献类型：
--
作者：
Bonangelino, CJ;Catlett, NL;Weisman, LS
在细胞分裂过程中，酿酒酵母的液泡在母细胞和子细胞之间分配。一部分亲本液泡膜移动到芽中，最终膜断裂将液泡分成两个独立的结构，在这里，我们描述了两个酵母突变导致液泡膜断裂缺陷，vac 7 -1和vac 14 -1。第三个突变体afab 1 -2菌株在非相关筛选中分离（A. Yamamoto等人，梅尔. h Cell 6：525-539，1995）共享vac 7 -1和vac 14 -1菌株的空泡表型。与野生型不同，突变体液泡不是多叶结构;在许多情况下，单个液泡跨越母体和芽，在母体-芽颈中具有明显的间隙。因此，即使在膜紧密相对的地方，液泡分裂也被阻止了。简单地扩大液泡不会产生这种突变表型。这些突变体的另一个共同表型是液泡酸化缺陷;然而，大多数其他液泡酸化突变体中的液泡断裂是正常的。液泡膜脂质的改变可以解释液泡膜断裂和酸化缺陷。由于定向筛选没有发现额外的III类互补基团，因此很可能所有三个基因都参与了类似的过程。有趣的是，FAB 1，以前被证明编码一个假定的磷脂酰肌醇-4-磷酸5-激酶。此外，FAB 1的过表达抑制了vac 14 -1突变，这表明VAC 14和FAB 1在一个共同的步骤起作用，VAC 7编码一种新的128 kDa蛋白，定位于液泡膜。Vac 7 p的这个位置与其参与液泡形态和遗传一致。
During cell division, the vacuole of Saccharomyces cerevisiae partitions between mother and daughter cells. A portion of the parental vacuole membrane moves into the bud, and ultimately membrane scission divides the vacuole into two separate structures, Here we characterize two yeast mutations causing defects in vacuole membrane scission, vac7-1 and vac14-1. A third mutant, afab1-2 strain, isolated in a nonrelated screen (A. Yamamoto et al., Mel. Biol. Cell 6:525-539, 1995) shares the vacuolar phenotypes of the vac7-1 and vac14-1 strains. Unlike the wild type, mutant vacuoles are not multilobed structures; in many cases, a single vacuole spans both the mother and bud, with a distinct gap in the mother-bud neck. Thus, even,where the membranes are closely opposed, vacuole fission is arrested. Simply enlarging the vacuole does not produce this mutant phenotype. An additional common phenotype of these mutants is a defect in vacuole acidification; however, vacuole scission in most other vacuole acidification mutants is normal. An alteration in vacuole membrane lipids could account for both the vacuole membrane scission and acidification defects. Because a directed screen has not identified additional class III complementation groups, it is likely that all three genes are involved in a similar process. Interestingly, FAB1, was previously shown to encode a putative phosphatidylinositol-4-phosphate 5-kinase. Moreover, overexpression of FAB1 suppresses the vac14-1 mutation, which suggests that VAC14 and FAB1 act at a common step, VAC7 encodes a novel 128-kDa protein that is localized at the vacuole membrane. This location of Vac7p is consistent with its involvement in vacuole morphology and inheritance.