The CGRP receptor can couple via pertussis toxin sensitive and insensitive G proteins

Swiss 3T3 cell lines mere constructed co-expressing receptor activity modifying protein (RAMP) 1 with the calcitonin receptor-like receptor (CRLR), and showed I-125-calcitonin-gene-related peptide (CGRP) 1 binding indicative of a type I CGRP receptor. Application of CGRP1 led to an increase in cAMP, which in 2/5 cell lines mas augmented following pertussis toxin (PTX) pre-treatment. In Xenopus oocytes, expression of RAMP1, which potentiates an endogenous CGRP receptor, led to constitutive activation of co-expressed GIRK potassium channels. This potassium current vas increased following CGRP application or co-expression of CRLR, but decreased by PTX or co-expression of transducin, We conclude that the CGRP receptor can signal to both PTX sensitive and insensitive G proteins. (C) 1998 Federation of European Biochemical Societies.