Campanelli J T, Roberds S L, Campbell K P, Scheller R H
Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University, California 94305.
Cell. 1994 Jun 3;77(5):663-74. doi: 10.1016/0092-8674(94)90051-5.
Synapse formation is characterized by the accumulation of molecules at the site of contact between pre- and postsynaptic cells. Agrin, a protein implicated in the regulation of this process, causes the clustering of acetylcholine receptors (AChRs). Here we characterize an agrin-binding site on the surface of muscle cells, show that this site corresponds to alpha-dystroglycan, and present evidence that alpha-dystroglycan is functionally related to agrin activity. Furthermore, we demonstrate that alpha-dystroglycan and adhalin, components of the dystrophin-associated glycoprotein complex, as well as utrophin, colocalize with agrin-induced AChR clusters. Thus, agrin may function by initiating or stabilizing a synapse-specific membrane cytoskeleton that in turn serves as a scaffold upon which synaptic molecules are concentrated.
突触形成的特征是分子在突触前和突触后细胞接触部位的积累。聚集蛋白是一种参与该过程调节的蛋白质，可导致乙酰胆碱受体（AChRs）聚集。在此，我们对肌肉细胞表面的一个聚集蛋白结合位点进行了表征，表明该位点对应于α - 肌营养不良聚糖，并提供证据表明α - 肌营养不良聚糖在功能上与聚集蛋白活性相关。此外，我们证明肌营养不良蛋白相关糖蛋白复合物的成分α - 肌营养不良聚糖和整合素，以及抗肌萎缩蛋白，与聚集蛋白诱导的AChR簇共定位。因此，聚集蛋白可能通过启动或稳定突触特异性膜细胞骨架来发挥作用，而该细胞骨架反过来又作为一个支架，使突触分子得以集中。
