The nAChRs are ligand-gated ion channels, and, like other members of the "cys-loop" ligand-gated ion channel superfamily, are composed of five protein subunits symmetrically arranged like staves around a barrel.
The nAChR is found at the edges of junctional folds at the neuromuscular junction on the postsynaptic side; it is activated by acetylcholine release across the synapse.