The Nicotinic Acetylcholine Receptor (nAChR) is a membrane receptor protein found on skeletal muscles, which is responsible for signal transduction between nerves and muscles. The binding of the ligand acetylcholine to the nAChR molecule, leads to a conformation change resulting in the opening of an ion-conducting channel across the plasma membrane. The mature functional protein is composed of four subunits - alpha, beta, gamma/epsilon, and delta. The gamma polypeptide of this protein is coded for by the CHRNG gene. In fetal and denervated muscles, the nAChR protein contains the gamma polypeptide. This forms a low-conductance, long open-end channel, which is distributed throughout the fiber length. In adults, however, the CHRNG is expressed in only very small amounts, so that the channel contains the epsilon polypeptide, and is of high-conductance, brief open type.
Mutations in the CHRNG gene have been implicated in the development of the lethal type and Escobar variant forms of multiple pterygium syndrome.