Identification of the plasma membrane proteolipid protein as a constituent of brain coated vesicles and synaptic plasma membrane.
Identification of the plasma membrane proteolipid protein as a constituent of brain coated vesicles and synaptic plasma membrane.
复制标题
鉴定质膜蛋白脂质蛋白作为脑包被囊泡和突触质膜的成分。
DOI：
10.1111/j.1471-4159.1988.tb01829.x
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发表时间：
1988
影响因子：
4.7
通讯作者：
Masur,SK
中科院分区：
文献类型：
--
作者：
Sapirstein,VS;Nolan,C;Stern,R;Ciocci,M;Masur,SK
我们已经分析了脑包被囊泡和突触质膜的质膜蛋白脂质蛋白的存在。从小牛脑灰质中分离包被的囊泡，并在Sephacryl S-1000上进行最终纯化，并通过色谱法重新分离两次以确保均匀性。通过凝胶电泳、网格蛋白重链免疫印迹和电子显微镜分析馏分。使用免疫印迹分析，我们能够证明在这些包被的囊泡中存在显著水平的质膜蛋白脂质蛋白（即，约占这些囊泡的双层蛋白的1%）。包被囊泡的再分离没有减少该部分中蛋白质的浓度。去除网格蛋白外壳蛋白或暴露于0.1MNa2CO3的包被囊泡表明，质膜蛋白脂质蛋白未被删除在脱壳和裂解，但这些囊泡的膜双层固有的。这些研究表明，质膜蛋白脂质蛋白代表了大量的双层蛋白包被囊泡，这表明这些囊泡可能是一个运输工具的质膜蛋白脂质蛋白的细胞内运动。从成年大鼠脑中分离突触质膜并使用免疫印迹法估计质膜蛋白脂质蛋白含量证实了早期研究，该研究表明该蛋白质也以高水平（约1 - 2%）存在于该膜部分中。这种蛋白质在突触质膜中的水平表明，突触质膜是这些囊泡可能靶向的一个主要位点，或者是蛋白质被回收的一个主要位点。
We have analyzed brain coated vesicles and synaptic plasma membrane for the presence of the plasma membrane proteolipid protein. Coated vesicles were isolated from calf brain gray matter with a final purification on Sephacryl S‐1000 and reisolated twice by chromatography to ensure homogeneity. Fractions were analyzed by gel electrophoresis, immunoblotting for clathrin heavy chain, and by electron microscopy. Using an immunoblotting assay we were able to demonstrate the presence of the plasma membrane proteolipid protein in these coated vesicles at a significant level (i.e., approximately 1% of the bilayer protein of these vesicles). Reisolation of coated vesicles did not diminish the concentration of the protein in this fraction. Removal of the clathrin coat proteins or exposure of the coated vesicles to 0.1MNa2CO3showed that the plasma membrane proteolipid protein is not removed during uncoating and lysis but is intrinsic to the membrane bilayer of these vesicles. These studies demonstrate that plasma membrane proteolipid protein represents a significant amount of the bilayer protein of coated vesicles, suggesting that these vesicles may be a transport vehicle for the intracellular movement of the plasma membrane proteolipid protein. Isolation of synaptic plasma membranes from adult rat brain and estimation of the plasma membrane proteolipid protein content using the immunoblotting method confirmed earlier studies that show this protein is present in this membrane fraction at high levels as well (approximately 1‐2%). The level of this protein in the synaptic plasma membrane suggests that the synaptic plasma membrane is one major site to which these vesicles may be targeted or from which the protein is being retrieved.