Class B GPCR: Receptors and RAMPs

Abstract

Receptor activity-modifying proteins (RAMPs) are a family of three single transmembrane spanning proteins. They were first identified based on their ability to facilitate the cell surface expression of a G protein-coupled receptor (GPCR), named the calcitonin receptor-like receptor (CLR). They also determine whether CLR can be activated by calcitonin-gene related peptide (CGRP) or adrenomedullin (AM). We now know that RAMPs can interact with a number of GPCRs, including the calcitonin receptor. The interaction between a GPCR and RAMP can influence cell surface expression and trafficking, determine hormone specificity and regulate intracellular signaling and/or G protein-coupling in a receptor-specific manner. This chapter will review recent advances in the RAMP field, paying particular attention to receptors formed by the co-expression of CLR and RAMPs. We will detail the known GPCR partners for RAMPs and describe how these interactions with RAMP can influence GPCR function.