The acetylcholine (nicotinic cholinergic) receptor protein comprises of 1 beta, 1 gamma, 1 delta, and 2 alpha subunits. CHRNB1 encodes the beta subunit of the receptor which functions on the postsynaptic side of the neuromuscular junction. Acetylcholine binds these receptors and activates membrane ion channel pores on the motor end plate, mediating electric signaling between nerve and muscle cells.
Defective CHRNB1 has been associated with slow-channel myasthenic syndrome 2A and 2C. Myasthenia syndromes are characterized by extended acetylcholine receptor activity, prolonged motor endplate currents, and cationic overload. These factors result in motor endplate myopathy as well as remodeling of the post-synaptic membrane and degeneration of folds at the neuromuscular junction.