GLYCOSPHINGOLIPID-ENRICHED, DETERGENT-INSOLUBLE COMPLEXES IN PROTEIN SORTING IN EPITHELIAL-CELLS
GLYCOSPHINGOLIPID-ENRICHED, DETERGENT-INSOLUBLE COMPLEXES IN PROTEIN SORTING IN EPITHELIAL-CELLS
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DOI：
10.1021/bi00076a009
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发表时间：
1993-06-29
期刊：
影响因子：
2.9
通讯作者：
SIMONS, K
中科院分区：
文献类型：
--
作者：
FIEDLER, K;KOBAYASHI, T;SIMONS, K
在简单上皮细胞中，细胞顶端和底外侧蛋白的传递是通过反式高尔基网络的分选和单独的囊泡载体进行的。为了确定参与蛋白质分选的分子机制，我们最近研究了Madin-Darby犬肾（MDCK）细胞中清洁剂-不溶性复合物，在CHAPS提取外胞载体囊泡后，特别是包括顶端标记蛋白流感血凝素（HA）。此前，一种富含糖基磷脂酰肌醇锚定（GPI）蛋白和糖脂的Triton X-100不溶性膜残基被表征并参与了向顶端细胞表面的运输[Brown， D, & Rose， J. (1991) cell, 68, 533-544]。在本报告中，通过二维凝胶分析比较了CHAPS和Triton复合物的蛋白质组成。在这些复合物中只发现了几种主要的膜蛋白。蛋白质组成在质量上相似，但在单个成分上有定量差异。CHAPS复合体缺少gpi连接蛋白，保留了少量与Triton X-100不溶性复合体组成相似的脂质。我们提出，在体内，这些复合物构成了一个分选平台的一部分，该平台介导了蛋白质的分离和向顶端细胞表面的传递。
In simple epithelial cells, the delivery of apical and basolateral proteins to the cell surface is mediated by sorting in the trans-Golgi network and transport via separate vesicular carriers. In order to identify the molecular machinery involved in protein sorting, we have recently studied a detergent-insoluble complex in Madin-Darby canine kidney (MDCK) cells, following CHAPS extraction of exocytic carrier vesicles, specifically including the apical marker protein influenza hemagglutinin (HA). Previously, a Triton X-100 insoluble membrane residue that was enriched in glycosylphosphatidylinositol-anchored (GPI) proteins and glycolipids was characterized and implicated in transport to the apical cell surface [Brown, D., & Rose, J. (1991) Cell 68, 533-544]. In this report, the protein compositions of the CHAPS and Triton complexes have been compared by two-dimensional gel analysis. Only a few major membrane proteins are found in the complexes. The protein compositions are qualitatively similar, but differ quantitatively in the individual components. The CHAPS complex is depleted of GPI-linked proteins and retains a minor fraction of lipids similar in composition to that of the Triton X-100 insoluble complex. We propose that in vivo the complexes form part of a sorting platform that mediates protein segregation and delivery to the apical cell surface.