Zick Michael, Stroupe Christopher, Orr Amy, Douville Deborah, Wickner William T
Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, United States.
Elife. 2014 Jan 1;3:e01879. doi: 10.7554/eLife.01879.
Like other intracellular fusion events, the homotypic fusion of yeast vacuoles requires a Rab GTPase, a large Rab effector complex, SNARE proteins which can form a 4-helical bundle, and the SNARE disassembly chaperones Sec17p and Sec18p. In addition to these proteins, specific vacuole lipids are required for efficient fusion in vivo and with the purified organelle. Reconstitution of vacuole fusion with all purified components reveals that high SNARE levels can mask the requirement for a complex mixture of vacuole lipids. At lower, more physiological SNARE levels, neutral lipids with small headgroups that tend to form non-bilayer structures (phosphatidylethanolamine, diacylglycerol, and ergosterol) are essential. Membranes without these three lipids can dock and complete trans-SNARE pairing but cannot rearrange their lipids for fusion. DOI: http://dx.doi.org/10.7554/eLife.01879.001.
与其他细胞内融合事件一样，酵母液泡的同型融合需要一种Rab GTP酶、一个大型Rab效应器复合体、能够形成四螺旋束的SNARE蛋白以及SNARE拆解分子伴侣Sec17p和Sec18p。除了这些蛋白质外，体内和纯化细胞器的高效融合还需要特定的液泡脂质。用所有纯化成分重建液泡融合表明，高SNARE水平可以掩盖对复杂液泡脂质混合物的需求。在较低的、更接近生理水平的SNARE浓度下，具有小头基团且倾向于形成非双层结构的中性脂质（磷脂酰乙醇胺、二酰基甘油和麦角固醇）至关重要。没有这三种脂质的膜可以对接并完成反式SNARE配对，但无法重新排列其脂质以实现融合。DOI: http://dx.doi.org/10.7554/eLife.01879.001
