ISOLATION AND CHARACTERIZATION OF PERIAXOLEMMAL AND AXOLEMMAL ENRICHED MEMBRANE-FRACTIONS FROM THE RAT CENTRAL-NERVOUS-SYSTEM
ISOLATION AND CHARACTERIZATION OF PERIAXOLEMMAL AND AXOLEMMAL ENRICHED MEMBRANE-FRACTIONS FROM THE RAT CENTRAL-NERVOUS-SYSTEM
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DOI：
10.1002/jnr.490320415
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发表时间：
1992-08-01
影响因子：
4.2
通讯作者：
FISCHER, I
中科院分区：
文献类型：
--
作者：
SAPIRSTEIN, VS;DURRIE, R;FISCHER, I
在这份报告中，我们描述了将大鼠下脑干的粗轴膜部分分级分离为富含轴膜周髓鞘或轴膜标记物的亚部分。这些亚组分在0.8M和1.0M蔗糖上分层的密度梯度上分离。两个亚组分均由单层囊泡组成。相对于从相同起始材料纯化的髓磷脂，0.8M亚级分富含MAG、CN酶、碳酸酐酶和Na+，K+ ATP酶，但PLP和MBP极低。此外，该级分表现出与髓磷脂不同的蛋白质谱。1.0M组分也高度富集Na+，K+ ATP酶，并具有与0.8M亚组分相似的总体组成。然而，它不同于0.8 M亚组分，MAG，CNG 4和碳酸酐酶低，但富含电压依赖性Na+通道，轴突特异性胞衬蛋白和MAP-1B。基于这些特征，我们得出结论，0.8M和1.0M亚组分分别高度富集在轴膜周髓鞘和轴膜中。Plasmolipin 10是独特的，在髓磷脂和0.8M和1.0M亚组分中具有同样高的水平。相对于髓鞘，这两个亚组分都富含GTP结合蛋白Go的α亚基和所有G蛋白GA/1共有的α亚基。与膜亚组分融合的脂质双层的电生理学表明，这两种膜包含组的K+和Cl-通道，这是基于通道的大小和开放时间，在很大程度上彼此不同。
In this report, we describe the fractionation of crude axolemmal fractions from rat lower brainstem into subfractions enriched in markers for either periaxolemmal myelin or axolemma. These subfractions were isolated on density gradients as bands layering on 0.8M and 1.0M sucrose. Both subfractions consisted of unilamellar vesicles. Relative to myelin purified from the same starting material, the 0.8M subfraction was enriched in MAG, CNPase, carbonic anhydrase and Na+, K+ ATPase but was extremely low in PLP and MBP. In addition, this fraction exhibited a protein profile distinct from myelin. The 1.0M fraction was also highly enriched in Na+, K+ ATPase and had an overall composition similar to the 0.8M subfraction. However, it differed from the 0.8M subfraction by being low in MAG, CNPase, and carbonic anhydrase, but enriched in voltage-dependent Na+ channel, axon-specific fodrin, and MAP-1B. Based on these characteristics we concluded that the 0.8M and 1.0M subfractions were highly enriched in periaxolemmal myelin and axolemmal membrane, respectively. Plasmolipin10 was unique with equally high levels in myelin and in the 0.8M and 1.0M subfractions. Both subfractions were enriched, relative to myelin, in the alpha subunit of the GTP binding protein, Go, and the alpha subunit common to all G proteins, GA/1. Electrophysiology with membrane subfractions fused to lipid bilayers showed that both membranes contained sets of K+ and Cl- channels, which based on channel sizes and open times, are largely distinct from one another.