The CHRNE gene provides instructions for making the epsilon (ε) component (subunit) of the acetylcholine receptor (AChR) protein. The AChR protein is found in the membrane of skeletal muscle cells and plays a critical role in the neuromuscular junction, which is the area where signaling between nerve and muscle cells occurs. Signaling between nerve and muscle cells is necessary for movement. The AChR protein consists of five subunits, each of which is produced from a different gene. The subunits are assembled into the AChR protein in the endoplasmic reticulum, a cell structure involved in protein processing and transport, before being transported to the cell membrane. There are two major forms of the AChR protein, a fetal type that is present before birth and an adult type. The ε subunit is found only in the adult AChR protein. At about the 33rd week of pregnancy, the ε subunit replaces the gamma (γ) subunit (found only in fetal AChR) to form adult AChR protein.