A sequence motif responsible for ER export and surface expression of Kir2.0 inward rectifier K+ channels

Integral membrane proteins are sorted va the secretory pathway. It was proposed that this pathway is nonselective provided that the cargo protein is properly assembled and lacks an endoplasmic reticulum (ER) retention signal, However, recent experimental evidence suggests that efficient export of proteins from the ER to the Golgi complex is not simply a default pathway. Here we demonstrate a novel sequence motif (FsYENEV) in the cytoplasmic C-terminus of mammalian inward rectifier potassium (Kir) channels which determines ER export, This motif is found to be both necessary and sufficient for efficient export from the ER that eventually leads to efficient surface expression of Kir2.1 channels. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V, All rights reserved,