Receptor-associated protein of the synapse (rapsyn)

Receptor-associated protein of the synapse (rapsyn) is a cytoplasmic protein encoded by the RAPSN gene and is essential for the normal formation and maintenance of synapses at the neuromuscular junction. Rapsyn anchors and clusters nicotinic acetylcholine receptors (AChRs) at postsynaptic membranes by linking them to the postsynaptic cytoskeleton, likely through direct association with proteins such as actin or spectrin. Loss-of-function mutations in RAPSN disrupt AChR clustering, leading to congenital myasthenic syndrome (CMS), a disorder characterized by muscle weakness and fatigability. Rapsyn is not a receptor, enzyme, or transporter but is critical for receptor localization and synaptic integrity. Disease-causing mutations in RAPSN, most commonly N88K, can reduce the stability of AChR clusters, and patients often respond to acetylcholinesterase inhibitors and other neuromodulatory drugs[1][3][5].

Other names

RapsynRAPSNRNF205RING finger protein 205receptor-associated protein of the synapse

Indirect modulation via enhancement of acetylcholine signaling at the neuromuscular junction (e.g., inhibition of acetylcholinesterase), stabilization of acetylcholine receptor clusters