Two distinct populations of synaptic-like vesicles from rat brain.
Two distinct populations of synaptic-like vesicles from rat brain.
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来自大鼠大脑的两个不同的突触样囊泡群体。
DOI：
10.1073/pnas.95.1.183
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发表时间：
1998
影响因子：
11.1
通讯作者：
Kandror,KV
中科院分区：
文献类型：
--
作者：
Thoidis,G;Chen,P;Pushkin,AV;Vallega,G;Leeman,SE;Fine,RE;Kandror,KV
在非神经元细胞中，几种质膜蛋白如外表面酶、受体和离子通道通过内体途径在其细胞内区室和细胞表面之间循环。然而，在神经元中，这种途径尚未得到广泛的表征。特别是，目前还不清楚它是否与小突触囊泡的再循环有关，小突触囊泡是神经末梢膜运输的主要途径。为了解决这个问题，我们纯化和研究了大鼠脑突触体的囊泡组分。两个不同的群体的小泡具有不同的浮力密度和沉降系数，检测在这一部分通过蔗糖梯度离心和Western印迹分析的个别蛋白质。这两个群体都含有作为突触囊泡标志物的蛋白质，即SV 2、突触结合蛋白、突触泡蛋白、分泌性载体膜蛋白（SCAMP）、小突触泡蛋白和rab3a。这两个群体之间的一个显着差异是精氨酸氨肽酶活性（以前建议的标志物调节内体再循环途径）的存在下，专门在较轻的低密度囊泡。同样的两个囊泡的人口中也检测到网格蛋白包被的囊泡分离的整个大鼠脑或纯化的突触体后，除去其网格蛋白外套孵育在pH 8.5的制备。因此，我们得出结论，这两种类型的囊泡循环突触体通过网格蛋白介导的途径。这些数据提供了实验证据，在大鼠脑突触样囊泡的生化异质性。
In nonneuronal cells, several plasma membrane proteins such as exofacial enzymes, receptors, and ion channels recycle between their intracellular compartment(s) and the cell surface via an endosomal pathway. In neurons, however, this pathway has not been extensively characterized. In particular, it remains unclear whether or not it is related to the recycling of small synaptic vesicles, the major pathway of membrane traffic in nerve terminals. To approach this problem, we purified and studied a vesicular fraction from rat brain synaptosomes. Two distinct populations of vesicles with different buoyant densities and sedimentation coefficients were detected in this fraction by sucrose gradient centrifugation and Western blot analysis of the individual proteins. Both populations contain proteins that are markers of synaptic vesicles, namely, SV2, synaptotagmin, synaptophysin, secretory carrier membrane proteins (SCAMPs), synaptobrevin, and rab3a. A striking difference between the two populations is the presence of arginine aminopeptidase activity (a previously suggested marker for the regulated endosomal recycling pathway) exclusively in the lighter less-dense vesicles. The same two vesicular populations were also detected in the preparation of clathrin-coated vesicles isolated from whole rat brain or purified synaptosomes after removal of their clathrin coats by incubation at pH 8.5. We conclude, therefore, that both types of vesicles recycle in synaptosomes via a clathrin-mediated pathway. These data present experimental evidence for biochemical heterogeneity of synaptic-like vesicles in rat brain.