Interaction of rapsyn with GABA A receptor in fibroblasts

Rapsyn, a 43kDa protein associated with the cytoplasmic face of the postsynaptic membrane at skeletal neuromuscular junction, is essential for clustering acetylcholine receptors (AChR) at the synapse (Gautam, et al., 1995). When rapsyn was transfected into the fibroblast cell line, QT-6, it formed discrete membrane domains. When rapsyn was co-transfected together with subunits of AChR into the QT-6 cells, AChR become clustered at these domains, suggesting that rapsyn binds and immobilises AChR in these domains (Phillips et al. 1991a). This study examined the specificity of the clustering activity of rapsyn by co-transfecting QT-6 cells with rapsyn in combination with either the human GABA-A receptor (a1, b1 and y2 subunits together) or the adult human skeletal muscle sodium channel