Receptor activity-modifying protein

Receptor activity-modifying proteins (RAMPs) are a class of protein that interact with and modulate the activities of several Class B G Protein-Coupled Receptors including the receptors for secretin, calcitonin (CT), glucagon, and vasoactive intestinal peptide (VIP). There are three distinct types of RAMPs, designated RAMP1, RAMP2, and RAMP3, each encoded by a separate gene.

Function

Currently, the function of RAMPs is divided into classes activities. When associated with the Calcitonin receptor (CTR) or Calcitonin receptor-like (CALCRL) (below), RAMPs can change the selectivity of the receptor for a specific hormone. In the cases of the other receptors mentioned, however, there is no evidence that they can do this, but instead function to regulate trafficking of receptors from the ER / golgi to the membrane. These functions appear to be ones where there is redundancy, as neither RAMP1 nor RAMP3 knockout mice (KO) have grossly abnormal phenotypes. The likelihood is that the phenotype of RAMP2 KO mice is more connected with the abolition of most adrenomedullin (AM) signalling than effects on trafficking of other receptors, as those mice are almost identical to AM KO mice.

Types

Association of RAMPs with either the CT or CALCRL proteins forms 6 different receptors from the calcitonin receptor family:

GPCR	RAMP isoform	resultant receptor
Calcitonin receptor-like	RAMP1	CGRP
	RAMP2	adrenomedullin (AM) receptor, designated AM1
	RAMP3	dual CGRP/AM receptor, designated AM2
Calcitonin receptor	RAMP1	amylin receptor AMY1
	RAMP2	amylin receptor AMY2
	RAMP3	amylin receptor AMY3

External links

• Receptor activity modifying protein at the US National Library of Medicine Medical Subject Headings (MeSH)