Two mammalian proteins, vtila and vtilb, are homologous to the yeast Q-SNARE Vtilp which is part of several SNARE complexes in different transport steps. In vitro experiments suggest distinct functions for vtila and vtilb. Here we compared the subcellular localization of endogenous vtila and vtilb by immunofluorescence and immuno-electron microscopy. Both proteins had a distinct but overlapping localization. vtila was found predominantly on the Golgi and the TGN, vtilb mostly on tubules and vesicles in the TGN area and on endosomes. vti1a coimmunoprecipitated with VAMP-4, syntaxin 6, and syntaxin 16. These four SNAREs could assemble into a SNARE complex of conserved structure because one SNARE motif of each subgroup is present. vtila-beta, VAMP-4, syntaxin 6, and syntaxin 16 are coenriched with small synaptic vesicles and with clathrin-coated vesicles isolated from rat brain synaptosomes. Therefore, this SNARE complex may have a role in synaptic vesicle biogenesis or recycling.

中文翻译：

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SNARE vti1a和vti1b具有独特的本地化和SNARE复杂伙伴。

两种哺乳动物蛋白vtila和vtilb与酵母Q-SNARE Vtilp同源，后者是几种SNARE复合物在不同运输步骤中的一部分。体外实验表明vtila和vtilb具有不同的功能。在这里，我们通过免疫荧光和免疫电子显微镜比较了内源性vtila和vtilb的亚细胞定位。两种蛋白质都有独特但重叠的定位。vtila主要在高尔基体和TGN上发现，vtilb多见于TGN地区的小管和囊泡以及内体。vti1a与VAMP-4，syntaxin 6和syntaxin 16共免疫沉淀。这四个SNARE可以组装成一个保守结构的SNARE复合体，因为每个子组都有一个SNARE母题。vtila-beta，VAMP-4，syntaxin 6，和Syntaxin 16与小突触小泡和从大鼠脑突触小体分离的网格蛋白包被小泡共富集。因此，该SNARE复合物可能在突触小泡的生物发生或回收中起作用。