Sec17p和同型寡聚体蛋白分选复合物（HOPS）在不同的可溶性N-乙基马来酰胺敏感因子附着蛋白受体（SNARE）复合物中，介导SNARE复合物的破坏或组装以实现融合。
Sec17p and HOPS, in distinct SNARE complexes, mediate SNARE complex disruption or assembly for fusion.
作者信息
Collins Kevin M, Thorngren Naomi L, Fratti Rutilio A, Wickner William T
机构信息
Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA.
出版信息
EMBO J. 2005 May 18;24(10):1775-86. doi: 10.1038/sj.emboj.7600658. Epub 2005 May 5.
SNARE functions during membrane docking and fusion are regulated by Sec1/Munc18 (SM) chaperones and Rab/Ypt GTPase effectors. These functions for yeast vacuole fusion are combined in the six-subunit HOPS complex. HOPS facilitates Ypt7p nucleotide exchange, is a Ypt7p effector, and contains an SM protein. We have dissected the associations and requirements for HOPS, Ypt7p, and Sec17/18p during SNARE complex assembly. Vacuole SNARE complexes bind either Sec17p or the HOPS complex, but not both. Sec17p and its co-chaperone Sec18p disassemble SNARE complexes. Ypt7p regulates the reassembly of unpaired SNAREs with each other and with HOPS, forming HOPS.SNARE complexes prior to fusion. After HOPS.SNARE assembly, lipid rearrangements are still required for vacuole content mixing. Thus, Sec17p and HOPS have mutually exclusive interactions with vacuole SNAREs to mediate disruption of SNARE complexes or their assembly for docking and fusion. Sec17p may displace HOPS from SNAREs to permit subsequent rounds of fusion.
SNARE在膜对接和融合过程中的功能受Sec1/Munc18（SM）分子伴侣和Rab/Ypt GTP酶效应器调控。酵母液泡融合的这些功能由六亚基HOPS复合体整合。HOPS促进Ypt7p核苷酸交换，是Ypt7p效应器，并包含一个SM蛋白。我们剖析了SNARE复合体组装过程中HOPS、Ypt7p和Sec17/18p之间的关联及需求。液泡SNARE复合体要么结合Sec17p，要么结合HOPS复合体，但不会同时结合两者。Sec17p及其共分子伴侣Sec18p会拆解SNARE复合体。Ypt7p调节未配对SNARE之间以及它们与HOPS之间的重新组装，在融合前形成HOPS.SNARE复合体。HOPS.SNARE组装后，液泡内容物混合仍需要脂质重排。因此，Sec17p和HOPS与液泡SNARE具有相互排斥的相互作用，以介导SNARE复合体的拆解或组装，用于对接和融合。Sec17p可能会将HOPS从SNARE上置换下来，以允许后续轮次的融合。
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