Rab1 and Ca2+ are required for the fusion of carrier vesicles mediating endoplasmic reticulum to Golgi transport.
Rab1 and Ca2+ are required for the fusion of carrier vesicles mediating endoplasmic reticulum to Golgi transport.
复制标题
Rab1和Ca2+是将载体内质网融合到高尔基体转运的载体囊泡所必需的。
DOI：
10.1083/jcb.125.2.239
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发表时间：
1994-04
影响因子：
7.8
通讯作者：
Balch, W E
中科院分区：
文献类型：
--
作者：
Pind, S N;Nuoffer, C;McCaffery, J M;Plutner, H;Davidson, H W;Farquhar, M G;Balch, W E
Rab/YPT1/SEC4基因家族的小分子GTP酶家族成员在胞外途径的腔室之间的囊泡运输调节中起着关键作用。利用免疫电子显微镜，我们证明了一个显性的负性rab1a突变体rab1a(N124I)在体外存在鸟核苷酸结合缺陷，导致水泡性口炎病毒糖蛋白(VSV-G)在许多顺-高尔基前小泡和含有Rab1和Coom复合体的一个亚单位β-COP的囊泡管簇中积聚。与以前的观察结果类似(Balch等人1994年。牢房。76：841-852)，VSV-G在Rab1a(N124I)突变体存在下积累的泡状载体中浓缩近5-10倍。含有VSV-G的囊泡和囊泡-管状团也被发现在存在Rab1a效应域肽模拟物的情况下聚集，该模拟物可以抑制内质网到高尔基体的运输，以及在没有钙离子的情况下。这些结果表明，依赖于Ca(2+)的蛋白质的联合作用和与Rab1的GTPase循环相关的构象变化对于控制囊泡输送到高尔基体的晚期靶向/融合步骤是必不可少的。
Members of the rab/YPT1/SEC4 gene family of small molecular weight GTPases play key roles in the regulation of vesicular traffic between compartments of the exocytic pathway. Using immunoelectron microscopy, we demonstrate that a dominant negative rab1a mutant, rab1a(N124I), defective for guanine nucleotide binding in vitro, leads to the accumulation of vesicular stomatitis virus glycoprotein (VSV-G) in numerous pre-cis-Golgi vesicles and vesicular-tubular clusters containing rab1 and beta-COP, a subunit of the coatomer complex. Similar to previous observations (Balch et al. 1994. Cell. 76:841-852), VSV-G was concentrated nearly 5-10-fold in vesicular carriers that accumulate in the presence of the rab1a(N124I) mutant. VSV-G containing vesicles and vesicular-tubular clusters were also found to accumulate in the presence of a rab1a effector domain peptide mimetic that inhibits endoplasmic reticulum to Golgi transport, as well as in the absence of Ca2+. These results suggest that the combined action of a Ca(2+)-dependent protein and conformational changes associated with the GTPase cycle of rab1 are essential for a late targeting/fusion step controlling the delivery of vesicles to Golgi compartments.