Golgi Export of the Kir2.1 Channel Is Driven by a Trafficking Signal Located Within Its Tertiary Structure

A newly defined Golgi export signal uncovers an impor-tant quality control mechanism and identifies a novel AP1 interaction. The trafficking of ion channels to and from the cell surface has been an active area of investigation for some time now. A great deal has been accomplished in mapping some of the routes followed by various channels to and from the cell surface, in identifying motors and regulators with which they interact, and in defining trafficking signals within the chan-nels themselves.1–3 Among the trafficking signals harbored within ion channels themselves, signals for retention in and trafficking out of the endoplasmic reticulum (ER) are the best understood. Both types consist of short, linear amino acid sequences and appear to be relatively simple in their opera-tion. ER retention signals, for example, are thought to be generally exposed only in misfolded or not fully assemble