Discovering G Protein-Coupled Receptor Motifs Mediating Export from the Endoplasmic Reticulum

Similar to many other plasma membrane proteins, G protein-coupled receptors (GPCRs) are synthesized in the endoplasmic reticulum (ER). After proper assembly and folding, the receptors are transported from the ER through the Golgi to the cell surface. As the first step in the anterograde trafficking, exit from the ER of nascent GPCRs plays a crucial role in receptor biosynthesis and controls receptor expression at the cell surface, which in turn dictates the functionality of the receptors. Recent studies have revealed that GPCRs possess linear motifs that are required for their export from the ER. In this chapter, we will discuss experimental approaches to identify the GPCR motifs which regulate anterograde transport, specifically exit from the ER, by focusing on α_2B -adrenergic receptor.