Haas A, Wickner W
Department of Biochemistry, Dartmouth Medical School, NH 03775-3844, USA.
EMBO J. 1996 Jul 1;15(13):3296-305.
In Saccharomyces cerevisiae, vacuoles are inherited by the formation of tubular and vesicular structures from the mother vacuole, the directed projection of these structures into the bud and the homotypic fusion of these vesicles. We have previously exploited a cell-free inheritance assay to show that the fusion step of vacuole inheritance requires cytosol, ATP and the GTPase Ypt7p. Here we demonstrate, using affinity-purified antibodies and purified recombinant proteins, a requirement for Sec17p (yeast alpha-SNAP) and Sec18p (yeast NSF) in homotypic vacuole fusion in vitro. Thus, Sec17p and Sec18p, which are typically involved in heterotypic transport steps, can also be involved in homotypic organelle fusion. We further show that vacuole-to-vacuole fusion is stimulated by certain fatty acyl-coenzyme A compounds in a Sec18p-dependent fashion. Finally, our data suggest the presence of a cytosolic factor which activates vacuole membrane-bound Sec18p.
在酿酒酵母中，液泡通过母液泡形成管状和囊泡状结构、这些结构向芽中的定向投射以及这些囊泡的同型融合来遗传。我们之前利用无细胞遗传分析表明，液泡遗传的融合步骤需要胞质溶胶、ATP和GTP酶Ypt7p。在这里，我们使用亲和纯化抗体和纯化的重组蛋白证明，体外同型液泡融合需要Sec17p（酵母α-SNAP）和Sec18p（酵母NSF）。因此，通常参与异型运输步骤的Sec17p和Sec18p也可参与同型细胞器融合。我们进一步表明，某些脂肪酰辅酶A化合物以Sec18p依赖的方式刺激液泡与液泡的融合。最后，我们的数据表明存在一种激活液泡膜结合Sec18p的胞质因子。
