A small cytoplasmic region adjacent to the fourth transmembrane segment of the α7 nicotinic receptor is essential for its biogenesis

► We studied the role of a small cytoplasmic domain of the α7 nicotinic receptor on biogenesis. ► Single mutants showed the importance of several residues. ► Proline substitutions abolished membrane expression. ► Mature mutant receptors remained inside the cell. ► Elements in the domain influence receptor transport.