Characterization of the Transmembrane Molecular Architecture of the Dystroglycan Complex in Schwann Cells*
Characterization of the Transmembrane Molecular Architecture of the Dystroglycan Complex in Schwann Cells*
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雪旺细胞中肌营养不良聚糖复合物跨膜分子结构的表征*
DOI：
10.1074/jbc.274.12.8240
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
K. Matsumura
中科院分区：
文献类型：
--
作者：
F. Saito;T. Masaki;K. Kamakura;L. Anderson;S. Fujita;H. Fukuta;Y. Sunada;Teruo Shimizu;K. Matsumura
我们之前已经证明：1)外周神经中表达的是糖酐异常复合物，而不是肌聚糖复合物；2)α-糖酐异常复合物是一种细胞外层粘连蛋白-2结合蛋白，锚定在雪旺细胞膜中的β-糖酐异常蛋白上。在本研究中，我们研究了雪旺细胞中糖醛酸异常复合物的跨膜分子结构。β-肌营养不良聚糖的胞质结构域与抗肌营养不良蛋白的雪旺细胞特异性异构体Dp116共定位于靠近外膜的雪旺细胞胞质上。β-三磷酸甘聚糖主要通过其细胞质结构域的15个c端氨基酸与Dp116结合，但这些氨基酸并不是这两个蛋白相互作用的唯一原因。有趣的是，β-三聚聚糖沉淀抗体只沉淀了一小部分α-三聚聚糖，并且不会从周围神经提取物中沉淀层粘连蛋白和Dp116。我们的研究结果表明：1)Dp116是雪旺细胞膜下细胞骨架系统的一个组成部分，该系统锚定了雪旺细胞中的糖异常复合物；2)与横纹肌细胞相比，雪旺细胞中的糖异常复合物是脆弱的。我们认为，这种脆弱性可能归因于雪旺细胞中肌聚糖复合物的缺失。
We have demonstrated previously 1) that the dystroglycan complex, but not the sarcoglycan complex, is expressed in peripheral nerve, and 2) that α-dystroglycan is an extracellular laminin-2-binding protein anchored to β-dystroglycan in the Schwann cell membrane. In the present study, we investigated the transmembrane molecular architecture of the dystroglycan complex in Schwann cells. The cytoplasmic domain of β-dystroglycan was co-localized with Dp116, the Schwann cell-specific isoform of dystrophin, in the abaxonal Schwann cell cytoplasm adjacent to the outer membrane. β-dystroglycan bound to Dp116 mainly via the 15 C-terminal amino acids of its cytoplasmic domain, but these amino acids were not solely responsible for the interaction of these two proteins. Interestingly, the β-dystroglycan-precipitating antibody precipitated only a small fraction of α-dystroglycan and did not precipitate laminin and Dp116 from the peripheral nerve extracts. Our results indicate 1) that Dp116 is a component of the submembranous cytoskeletal system that anchors the dystroglycan complex in Schwann cells, and 2) that the dystroglycan complex in Schwann cells is fragile compared with that in striated muscle cells. We propose that this fragility may be attributable to the absence of the sarcoglycan complex in Schwann cells.
影响因子：
56.9
作者：
Cao, W;Henry, MD;Oldstone, MBA
通讯作者：
Oldstone, MBA