Multiple GTP-binding proteins regulate vesicular transport from the ER to Golgi membranes.
Multiple GTP-binding proteins regulate vesicular transport from the ER to Golgi membranes.
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DOI：
10.1083/jcb.119.5.1077
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发表时间：
1992-12
期刊：
影响因子：
--
通讯作者：
Balch WE
中科院分区：
文献类型：
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作者：
Schwaninger R;Plutner H;Bokoch GM;Balch WE
使用间接免疫荧光，我们已经检查了抑制ras相关的rab小GTP结合蛋白和异源三聚体G α β γ蛋白在ER到高尔基体转运中的功能的试剂的作用。从ER的输出被针对rab 1B的抗体和抑制ARF功能的NH 2末端肽抑制（Balch，W. E、R. A. Kahn和R.施瓦宁格1992. J.Biol.Chem.267：13053-13061），表明这两种小GTP结合蛋白对于转运囊泡的形成是必需的。从ER的输出也被mastoparan有效抑制，mastoparan是一种肽，其模拟七种跨膜受体的G蛋白结合区，激活异源三聚体G蛋白并将其从其同源受体解偶联。与此结果一致，纯化的β-γ亚基抑制VSV-G从ER的出口，表明运输囊泡组装的初始事件是由异源三聚体G蛋白调节的。相比之下，在GTP γ S或AIF（3-5）存在下的孵育导致转运蛋白在分布于整个细胞的细胞质中的点状前高尔基体中间体的不同群体中积累。最后，被认为拮抗rab蛋白与推定的下游效应分子的相互作用的肽在递送至顺式高尔基体区室之前的后续步骤抑制转运，类似于在不存在NSF或钙的情况下转运蛋白的积累位点（Plutner，H.，H. W. Davidson，J. Saraste，and W. E.巴尔奇。1992. 119：1097-1116）。这些结果与以下假设一致：多种GTP结合蛋白，包括异源三聚体G蛋白、ARF和rab 1，差异调节分泌途径早期隔室之间蛋白质转运的步骤。讨论了G蛋白偶联受体调控内质网蛋白质输出的概念。
Using indirect immunofluorescence we have examined the effects of reagents which inhibit the function of ras-related rab small GTP- binding proteins and heterotrimeric G alpha beta gamma proteins in ER to Golgi transport. Export from the ER was inhibited by an antibody towards rab1B and an NH2-terminal peptide which inhibits ARF function (Balch, W. E., R. A. Kahn, and R. Schwaninger. 1992. J. Biol. Chem. 267:13053-13061), suggesting that both of these small GTP-binding proteins are essential for the transport vesicle formation. Export from the ER was also potently inhibited by mastoparan, a peptide which mimics G protein binding regions of seven transmembrane spanning receptors activating and uncoupling heterotrimeric G proteins from their cognate receptors. Consistent with this result, purified beta gamma subunits inhibited the export of VSV-G from the ER suggesting an initial event in transport vesicle assembly was regulated by a heterotrimeric G protein. In contrast, incubation in the presence of GTP gamma S or AIF(3-5) resulted in the accumulation of transported protein in different populations of punctate pre-Golgi intermediates distributed throughout the cytoplasm of the cell. Finally, a peptide which is believed to antagonize the interaction of rab proteins with putative downstream effector molecules inhibited transport at a later step preceding delivery to the cis Golgi compartment, similar to the site of accumulation of transported protein in the absence of NSF or calcium (Plutner, H., H. W. Davidson, J. Saraste, and W. E. Balch. 1992. J. Cell Biol. 119:1097-1116). These results are consistent with the hypothesis that multiple GTP-binding proteins including a heterotrimeric G protein(s), ARF and rab1 differentially regulate steps in the transport of protein between early compartments of the secretory pathway. The concept that G protein-coupled receptors gate the export of protein from the ER is discussed.