The yeast v-SNARE Vti1p mediates two vesicle transport pathways through interactions with the t-SNAREs Sed5p and Pep12p.
The yeast v-SNARE Vti1p mediates two vesicle transport pathways through interactions with the t-SNAREs Sed5p and Pep12p.
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DOI：
10.1083/jcb.137.7.1511
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发表时间：
1997-06-30
期刊：
影响因子：
--
通讯作者：
Stevens TH
中科院分区：
文献类型：
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作者：
von Mollard GF;Nothwehr SF;Stevens TH
真核细胞中的膜运输需要运输囊泡上的特定v-SNARE与靶膜上的特定t-SNARE相互作用。我们发现了一种新的酿酒酵母v-SNARE（Vti 1 p）的必需基因，VTI 1编码。Vti 1 p与prevacuolar t-SNARE Pep 12 p相互作用，引导高尔基体进行prevacuolar运输。vti 1 -1突变体细胞错误分选，当vti 1 -1细胞被转移到限制性温度时，迅速可逆地分泌可溶性液泡水解酶羧肽酶Y（CPY）。然而，Pep 12 p的过表达抑制了vti 1 -1细胞在36°C下表现出的CPY分泌缺陷。第二个Vti 1突变体，Vti 1 -11的表征，揭示了Vti 1 p也发挥了作用，在膜交通在顺式高尔基体阶段。vti 1 -11突变体细胞表现出生长缺陷，并积累了ER和早期高尔基体形式的CPY和分泌蛋白转化酶在非允许的温度。过表达的酵母cis-Golgi t-SNARE Sed 5 p抑制积累的ER形式的CPY，但没有导致CPY运输到vti 1 -11细胞中的液泡。Sed 5 p的过表达允许在没有Vti 1 p的情况下生长。体外结合和免疫共沉淀研究表明，Vti 1 p直接与两个t-SNARE，Sed 5 p和Pep 12 p相互作用。这些数据表明，Vti 1 p在顺式高尔基体膜交通，这是必不可少的酵母菌的生存能力，并在高尔基体衍生的囊泡与prevacuolar室融合的一个非必要的作用中发挥作用。因此，一个单一的v-SNARE可以在功能上与两个不同的t-SNARE相互作用，指导酵母中的膜运输。
Membrane traffic in eukaryotic cells requires that specific v-SNAREs on transport vesicles interact with specific t-SNAREs on target membranes. We identified a novel Saccharomyces cerevisiae v-SNARE (Vti1p) encoded by the essential gene, VTI1. Vti1p interacts with the prevacuolar t-SNARE Pep12p to direct Golgi to prevacuolar traffic. vti1-1 mutant cells missorted and secreted the soluble vacuolar hydrolase carboxypeptidase Y (CPY) rapidly and reversibly when vti1-1 cells were shifted to the restrictive temperature. However, overexpression of Pep12p suppressed the CPY secretion defect exhibited by vti1-1 cells at 36°C. Characterization of a second vti1 mutant, vti1-11, revealed that Vti1p also plays a role in membrane traffic at a cis-Golgi stage. vti1-11 mutant cells displayed a growth defect and accumulated the ER and early Golgi forms of both CPY and the secreted protein invertase at the nonpermissive temperature. Overexpression of the yeast cis-Golgi t-SNARE Sed5p suppressed the accumulation of the ER form of CPY but did not lead to CPY transport to the vacuole in vti1-11 cells. Overexpression of Sed5p allowed growth in the absence of Vti1p. In vitro binding and coimmunoprecipitation studies revealed that Vti1p interacts directly with the two t-SNAREs, Sed5p and Pep12p. These data suggest that Vti1p plays a role in cis-Golgi membrane traffic, which is essential for yeast viability, and a nonessential role in the fusion of Golgi-derived vesicles with the prevacuolar compartment. Therefore, a single v-SNARE can interact functionally with two different t-SNAREs in directing membrane traffic in yeast.