Identification of rab2 as a tubulovesicle-membrane-associated protein in rabbit gastric parietal cells.
Identification of rab2 as a tubulovesicle-membrane-associated protein in rabbit gastric parietal cells.
复制标题
DOI：
10.1042/bj2850715
复制
发表时间：
1992-08
期刊：
影响因子：
--
通讯作者：
L. Tang;S. Stoch;I. Modlin;J. Goldenring
中科院分区：
文献类型：
--
作者：
L. Tang;S. Stoch;I. Modlin;J. Goldenring
Rab蛋白是ras样低分子量GTP结合蛋白，被认为是胞吐和胞吞作用中膜运输的特异性调节剂。先前，我们报道了兔胃壁细胞中的23 kDa微管囊泡相关GTP结合蛋白[Basson，Goldenring，Tang，刘易斯，Padfield，Jamieson & Modlin（1991）Biochem.J.279，43-48]。23 kDa蛋白质的主要组分现在被鉴定为rab 2。Rab 2共定位于壁细胞的小管囊泡膜。与GTP结合活性（如前所述）一致，在壁细胞的最大刺激下，rab 2免疫反应性从50，000 g重新分布到4000 g亚细胞膜部分。的tubulovesicle相关的rab 2表现为一个完整的膜蛋白，因为0.5 M-NaCl和0.1 M-碳酸盐提取未能从tubulovesicle膜中去除蛋白质。利用PCR技术从兔壁细胞中获得rab 2基因的cDNA序列，与人rab 2基因的cDNA序列相比，只有一个氨基酸的差异。本研究的结果提供了强有力的证据，壁细胞具有rab 2蛋白，这是紧密相关的tubulovesicle膜。
Rab proteins, which are ras-like low-molecular-mass GTP-binding proteins, are postulated to act as specific regulators of membrane trafficking in exocytosis and endocytosis. Previously, we reported a 23 kDa tubulovesicle-associated GTP-binding protein in rabbit gastric parietal cells [Basson, Goldenring, Tang, Lewis, Padfield, Jamieson & Modlin (1991) Biochem. J. 279, 43-48]. The major component of the 23 kDa protein is now identified as rab2. Rab2 was co-localized in tubulovesicle membranes from parietal cells. Consistent with GTP-binding activity (as documented before), upon maximal stimulation of parietal cells, rab2 immunoreactivity was redistributed from a 50,000 g to a 4000 g subcellular membrane fraction. The tubulovesicle-associated rab2 behaved as an integral membrane protein, since both 0.5 M-NaCl and 0.1 M-carbonate extraction failed to remove the protein from the tubulovesicle membrane. Utilizing a PCR the rab2 cDNA sequence from rabbit parietal cells was obtained, and it showed only one amino acid difference compared with the human sequence. The results of the present study provide strong evidence that parietal cells possess a rab2 protein which is tightly associated with tubulovesicle membranes.