Dystrophin and the dystrophin-associated glycoprotein, beta-dystroglycan, co-localize in photoreceptor synaptic complexes of the human retina
Dystrophin and the dystrophin-associated glycoprotein, beta-dystroglycan, co-localize in photoreceptor synaptic complexes of the human retina
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DOI：
10.1016/0306-4522(96)00069-3
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发表时间：
1996-07-01
期刊：
影响因子：
3.3
通讯作者：
Anderson, LVB
中科院分区：
文献类型：
--
作者：
Drenckhahn, D;Holbach, M;Anderson, LVB
编码肌营养不良蛋白（肌肉和几种非肌肉细胞的膜相关细胞骨架蛋白）的基因突变是杜氏肌营养不良症和佩克肌营养不良症的原因。患有Duchenne肌营养不良症的患者最近显示出视网膜电图的异常b波，表明肌营养不良蛋白对正常的视网膜传递是重要的。在视网膜中，抗肌萎缩蛋白定位于外丛状层中，其中抗肌萎缩蛋白与光感受器突触复合体的突触后标记物共定位。在本研究中，我们解决了两个主要的肌营养不良蛋白相关的肌质膜，β-肌营养不良蛋白聚糖和adhalin，是否也存在于光感受器突触复合体的膜蛋白的问题。通过双重免疫染色和免疫印迹，我们发现β-肌营养不良蛋白聚糖在人视网膜中表达，在那里它与肌营养不良蛋白共同定位在感光体突触复合物中，最有可能在突触后侧。视网膜中未检测到Adhalin。由于β-肌营养不良蛋白聚糖是跨膜超分子复合物的一员，被认为对神经肌肉接头的分化很重要，因此肌营养不良蛋白聚糖（与肌营养不良蛋白相关）也可能在光感受器突触的分化中发挥类似作用是一个有吸引力的假设。这项研究的进一步结果是，β-肌营养不良蛋白聚糖不仅存在于神经肌肉接头，但也与中枢神经系统的一个明确的突触复合体。这些研究结果表明，这种肌营养不良蛋白相关的膜蛋白在突触功能中发挥更广泛的作用。版权所有（C）1996 IBRO。
Mutations in the gene encoding for dystrophin, a membrane-associated cytoskeletal protein of muscle and several non-muscle cells, are the cause of Duchenne muscular dystrophy and Pecker muscular dystrophy. Patients suffering from Duchenne muscular dystrophy have recently been shown to display an abnormal b-wave of the electroretinogram, suggesting that dystrophin is important for normal retinal transmission. In the retina, dystrophin has been localized in the outer plexiform layer where dystrophin co-localizes with postsynaptic markers of photoreceptor synaptic complexes. In the present study we addressed the question of whether two major dystrophin-associted integral membrane proteins of the muscular plasma membrane, beta-dystroglycan and adhalin, are also present in photoreceptor synaptic complexes. By double immunostaining and immunoblotting we show here that beta-dystroglycan is expressed in the human retina where it co-localizes with dystrophin in photoreceptor synaptic complexes most likely on the postsynaptic side. Adhalin was not detected in the retina. Since beta-dystroglycan is a member of a transmembrane supramolecular complex thought to be important for differentiation of the neuromuscular junction, it is an attractive hypothesis that dystroglycan (linked to dystrophin) might also play a similar role in differentiation of the photoreceptor synapse. A further outcome of this study is that beta-dystroglycan is not only present in the neuromuscular junction but also associated with a well-defined synaptic complex of the central nervous system.These findings indicate a more general role of this dystrophin-associated membrane protein in synaptic functions. Copyright (C) 1996 IBRO.