Syntrophin binds to an alternatively spliced exon of dystrophin.
Syntrophin binds to an alternatively spliced exon of dystrophin.
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DOI：
10.1083/jcb.128.3.363
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发表时间：
1995-02
影响因子：
7.8
通讯作者：
Kunkel, L M
中科院分区：
文献类型：
--
作者：
Ahn, A H;Kunkel, L M
肌营养不良蛋白是杜氏肌营养不良基因座的蛋白质产物，是一种膜细胞骨架的蛋白质，与整合蛋白和膜相关蛋白的复合物结合。其中，58-kD 的细胞内膜相关蛋白，肌营养蛋白，最近被证明由三个相关但不同的基因组成的家族组成。我们使用体外转录/翻译系统在网织红细胞裂解物中表达人β1-肌营养不良蛋白的cDNA和人肌营养不良蛋白的COOH末端。使用抗肌营养不良蛋白抗体，我们在各种盐和洗涤剂条件下免疫沉淀这两种相互作用的蛋白。我们证明，在我们的测定中，抗肌营养不良蛋白外显子 74（一种可变剪接外显子）上编码的 53 个氨基酸对于与翻译的 β1-肌营养不良蛋白相互作用是必要且充分的。因此，基于其选择性剪接，肌营养不良蛋白可能存在于两个功能不同的群体中。在该重组表达系统中，肌营养不良蛋白相关蛋白、人肌营养不良蛋白相关蛋白（DRP 或 utropin）和来自鱼雷电器官的 87K 突触后蛋白也与翻译的 β1-肌营养不良蛋白结合。我们发现β1-肌营养蛋白的COOH末端37-kD片段足以与翻译的肌营养不良蛋白及其同源物相互作用，这表明β1-肌营养蛋白上的肌营养不良蛋白结合位点发生在三个肌营养不良蛋白同源物中保守的区域。
Dystrophin, the protein product of the Duchenne muscular dystrophy locus, is a protein of the membrane cytoskeleton that associates with a complex of integral and membrane-associated proteins. Of these, the 58- kD intracellular membrane-associated protein, syntrophin, was recently shown to consist of a family of three related but distinct genes. We expressed the cDNA of human beta 1-syntrophin and the COOH terminus of human dystrophin in reticulocyte lysates using an in vitro transcription/translation system. Using antibodies to dystrophin we immunoprecipitated these two interacting proteins in a variety of salt and detergent conditions. We demonstrate that the 53 amino acids encoded on exon 74 of dystrophin, an alternatively spliced exon, are necessary and sufficient for interaction with translated beta 1- syntrophin in our assay. On the basis of its alternative splicing, dystrophin may thus be present in two functionally distinct populations. In this recombinant expression system, the dystrophin relatives, human dystrophin related protein (DRP or utrophin) and the 87K postsynaptic protein from Torpedo electric organ, also bind to translated beta 1-syntrophin. We have found a COOH-terminal 37-kD fragment of beta 1-syntrophin sufficient to interact with translated dystrophin and its homologues, suggesting that the dystrophin binding site on beta 1-syntrophin occurs on a region that is conserved among the three syntrophin homologues.