The Saccharomyces cerevisiae v-SNARE Vti1p is required for multiple membrane transport pathways to the vacuole
The Saccharomyces cerevisiae v-SNARE Vti1p is required for multiple membrane transport pathways to the vacuole
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DOI：
10.1091/mbc.10.6.1719
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发表时间：
1999-06-01
影响因子：
3.3
通讯作者：
Stevens, TH
中科院分区：
文献类型：
--
作者：
von Mollard, GF;Stevens, TH
真核细胞的膜运输需要转运小泡上的V-SNARs和靶膜上的T-SNARs之间的相互作用。在这里，我们确定Vti1p是第一个被发现的V-SNARE蛋白，它是生物合成运输进入酵母液泡所必需的，相当于哺乳动物的溶酶体。某些Vti1-ts酵母突变体在碱性磷酸酶从高尔基体到液泡的运输以及氨基肽酶I从胞浆到液泡的靶向方面存在缺陷。VTI1与液泡T-SNARE VAM3基因相互作用，VAM3是碱性磷酸酶和氨基肽酶I运输到液泡所必需的。在同型液泡融合中，V-SNARE Nyv1p与Vam3p形成SNARE复合体；然而，我们发现Nyv1p不是通向液泡的三条生物合成途径中的任何一条所必需的。V-陷阱被认为确保了膜运输的特异性。然而，Vti1p还在另外两条膜信号通路中发挥作用：Vti1p在从TGN到前房室的交通中与t-Snares Pep12p相互作用，在逆行到顺高尔的交通中与Sed5p相互作用。Vti1p介导多个融合步骤的能力需要额外的蛋白质来确保膜交通的特异性。
The interaction between V-SNAREs on transport vesicles and t-SNAREs on target membranes is required for membrane traffic in eukaryotic cells. Here we identify Vti1p as the first V-SNARE protein found to be required for biosynthetic traffic into the yeast vacuole, the equivalent of the mammalian lysosome. Certain vti1-ts yeast mutants are defective in alkaline phosphatase transport from the Golgi to the vacuole and in targeting of aminopeptidase I from the cytosol to the vacuole. VTI1 interacts genetically with the vacuolar t-SNARE VAM3, which is required for transport of both alkaline phosphatase and aminopeptidase I to the vacuole. The V-SNARE Nyv1p forms a SNARE complex with Vam3p in homotypic vacuolar fusion; however, we find that Nyv1p is not required for any of the three biosynthetic pathways to the vacuole. V-SNAREs were thought to ensure specificity in membrane traffic. However, Vti1p also functions in two additional membrane traffic pathways: Vti1p interacts with the t-SNAREs Pep12p in traffic from the TGN to the prevacuolar compartment and with Sed5p in retrograde traffic to the cis-Golgi. The ability of Vti1p to mediate multiple fusion steps requires additional proteins to ensure specificity in membrane traffic.