Receptor activity-modifying protein dependent impairment of calcitonin receptor splice variant Δ(1-47)hCT((a)) function.

Summary of "Receptor activity-modifying protein dependent impairment of calcitonin receptor splice variant Δ(1-47)hCT((a)) function."

BACKGROUND AND
PURPOSE:
Alternative splicing expands proteome diversity to G protein-coupled receptors (GPCRs). Distinct receptor variants have been identified for a secretin family GPCR, the calcitonin receptor (CTR). The possible functional contributions of these receptor variants are further altered by their potential interactions with receptor activity-modifying proteins (RAMPs). One variant of the human CTR lacks the first 47 residues at its N terminus (Δ(1-47)hCT((a)) ). However, very little is known about the pharmacology of this variant or its ability to interact with RAMPs to form amylin receptors. EXPERIMENTAL
APPROACH:
Δ(1-47)hCT((a)) was characterised both with and without RAMPs in Cos7 and/or HEK293S cells. The receptor expression (ELISA assays) and function (cAMP and pERK1/2 assays) for up to six agonists and two antagonists were determined. KEY
RESULTS:
Despite lacking 47 residues at the N terminus, Δ(1-47)hCT((a)) was still able to express at the cell surface, but displayed a generalised reduction in peptide potency. Δ(1-47)hCT((a)) retained its ability to interact with RAMP1 and formed a functional amylin receptor; this also appeared to be the case with RAMP3. On the other hand, its interaction with RAMP2 and resultant amylin receptor was reduced to a greater extent. CONCLUSIONS AND
IMPLICATIONS:
Δ(1-47)hCT((a)) acts as a functional receptor at the cell surface. It exhibits altered receptor function, depending on whether it associates with a RAMP, and which RAMP it interacts with. Therefore, the presence of this variant in tissues will potentially contribute to altered peptide binding and signalling, depending on the RAMP distribution in tissues.

Affiliation

School of Biological Sciences, University of Auckland, New Zealand.

Journal Details

This article was published in the following journal.

Name: British journal of pharmacology
ISSN: 1476-5381
Pages:

Links

• PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22946511
• DOI: http://dx.doi.org/10.1111/j.1476-5381.2012.02197.x