Two birds with one stone: A novel motif for ACh receptor assembly quality control

Assembly of ACh receptors is under tight quality control. Only functional ACh receptors are expressed on the cell surface; unassembled subunits are retained in the endoplasmic reticulum (ER). In a recent elegant study, Wang and colleagues have identified a novel motif in the M1 domain of the ACh-receptor subunit that is responsible for ER retention and degradation of unassembled subunits. This signal appears to play an important role in regulating surface trafficking of functional ACh receptors.