ROLE FOR ADENOSINE-TRIPHOSPHATE IN REGULATING THE ASSEMBLY AND TRANSPORT OF VESICULAR STOMATITIS-VIRUS G PROTEIN TRIMERS
ROLE FOR ADENOSINE-TRIPHOSPHATE IN REGULATING THE ASSEMBLY AND TRANSPORT OF VESICULAR STOMATITIS-VIRUS G PROTEIN TRIMERS
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DOI：
10.1083/jcb.105.5.1957
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发表时间：
1987-11-01
影响因子：
7.8
通讯作者：
BALCH, WE
中科院分区：
文献类型：
--
作者：
DOMS, RW;KELLER, DS;BALCH, WE
我们的特点是水泡性口炎病毒（VSV）G蛋白获得其最终的寡聚体结构的过程中，使用密度梯度离心在温和的酸性蔗糖梯度。成熟的野生型VSV G蛋白是一种非共价结合的三聚体。三聚体组装从新合成的G单体与t1/2的6-8分钟。本地化的网站的三聚体和相关的三聚体形成与步骤之间的内质网（ER）和高尔基复合体的运输，我们研究了组装的温度敏感的突变体VSV株，ts 045的动力学。在非允许温度（39 ℃）下，C），ts 045 G蛋白不从ER转运。表型缺陷，抑制出口的ER在非允许的温度被认为是聚集的ts 045 G蛋白的积累。在转换到允许温度（32 ℃）之后，C），ts 045 G蛋白聚集体迅速解离（t1/2 < 1分钟）为单体G蛋白，其随后以与野生型G蛋白相同的动力学三聚化。只有三聚体被运送到高尔基复合体。动力学研究，以及在阻断ER向高尔基体转运的条件下发生三聚化的发现（在15和4 ℃下）。C），显示在ER中形成三聚体。耗尽细胞ATP抑制了ts 045 G蛋白聚集中间体的解离以及稳定三聚体的形成。结果表明，G蛋白的寡聚化发生在几个步骤中，对细胞ATP敏感，并且是从ER转运所必需的。
We have characterized the process by which the vesicular stomatitis virus (VSV) G protein acquires its final oligomeric structure using density-gradient centrifugation in mildly acidic sucrose gradients. The mature wild-type VSV G protein is a noncovalently associated trimer. Trimers are assembled from newly synthesized G monomers with a t1/2 of 6-8 min. To localize the site of trimerization and to correlate trimer formation with steps in transport between the endoplasmic reticulum (ER) and Golgi complex, we examined the kinetics of assembly of the temperature-sensitive mutant VSV strain, ts045. At the nonpermissive temperature (39.degree. C), ts045 G protein is not transported from the ER. The phenotypic defect that inhibited export from the ER at the nonpermissive temperature was found to be the accumulation of ts045 G protein in an aggregate. After being shifted to the permissive temperature (32.degree. C), the ts045 G protein aggregate rapidly dissociated (t1/2 < 1 min) to monomeric G protein which subsequently trimerized with the same kinetics as the wild-type G protein. Only trimers were transported to the Golgi complex. Kinetic studies, as well as the finding that trimerization occurred under conditions which block ER to Golgi transport (at both 15 and 4.degree. C), showed that trimers were formed in the ER. Depletion of cellular ATP inhibited both the dissociation of the aggregated intermediate of ts045 G protein as well as the formation of stable trimers. The results indicate that oligomerization of G protein occurs in several steps, is sensitive to cellular ATP, and is required for transport from the ER.