Basson M D, Goldenring J R, Tang L H, Lewis J J, Padfield P, Jamieson J D, Modlin I M
Department of Surgery, Yale University School of Medicine, New Haven, CT 06510.
Biochem J. 1991 Oct 1;279 ( Pt 1)(Pt 1):43-8. doi: 10.1042/bj2790043.
Small GTP-binding proteins are important regulators of intracellular traffic. The presence of several small GTP-binding proteins was documented in subfractions of rabbit parietal cells. Upon maximal stimulation of the cells with a combination of histamine and forskolin, one 23 kDa GTP-binding band was observed to decrease in a 50,000 g membrane fraction while increasing in 4000 g membranes. The 23 kDa band resolved into one major and two minor species on two-dimensional gels. GTP-binding species of 23 kDa, 24 kDa and 25 kDa were present in purified preparations of tubulovesicles. The three isoelectric species of the 23 kDa proteins observed in parietal cell 50,000 g microsomes were enriched in tubulovesicle preparations. None of the tubulovesicle-associated GTP-binding proteins were substrates for ADP-ribosylation by a preparation of botulinum D toxin. These results indicate that tubulovesicles contain discrete small GTP-binding proteins which redistribute during parietal cell stimulation.
小GTP结合蛋白是细胞内运输的重要调节因子。在兔壁细胞的亚组分中发现了几种小GTP结合蛋白。在用组胺和福斯高林联合最大程度刺激细胞后，观察到一条23 kDa的GTP结合带在50,000 g膜组分中减少，而在4000 g膜中增加。这条23 kDa的带在二维凝胶上分离为一个主要条带和两个次要条带。23 kDa、24 kDa和25 kDa的GTP结合条带出现在纯化的微管泡制剂中。在壁细胞50,000 g微粒体中观察到的23 kDa蛋白的三种等电条带在微管泡制剂中富集。微管泡相关的GTP结合蛋白均不是肉毒杆菌D毒素制剂进行ADP核糖基化的底物。这些结果表明，微管泡含有离散的小GTP结合蛋白，它们在壁细胞刺激过程中会重新分布。
