Background of the antigen
Agrin is a neuronal aggregating factor that induces the aggregation of acetylcholine receptors and other postsynaptic proteins on muscle fibers and is crucial for the formation of the neuromuscular junction. Agrin is an essential extracellular matrix component which promotes clustering of nicotinic acetylcholine receptors (nAChRs) and other proteins during development at the neuromuscular junction. Agrin, MuSK and Rapsyn are all essential components for AChR aggregation, through an unknown mechanism. The C-terminal region of agrin is released into the medium, interacts with receptors on the muscle surface and induces AChR aggregation. The central region contains two O-linked glycosylation sites and a domain homologous to domain III of laminin. The N-terminal region anchors agrin to the extracellular matrix via other basal membrane components. This region also contains a protease inhibitor domain and glycosaminoglycan attachment sites; increasing the predicted MW from 200kDa to ~600kDa.
