Characterization of a novel VPAC(1) selective agonist and identification of the receptor domains implicated in the carboxyl-terminal peptide recognition.
Vasoactive Intestinal Polypeptide (VIP) interacts with a high affinity to two subclasses of G protein coupled receptors named VPAC(1) and VPAC(2), and has a 3 - 10 fold preference for VPAC(1) over VPAC(2) receptors. Selective ligands for each receptor subclass were recently described. [R(16)]-PACAP (1 - 23) and [L(22)]-VIP are two selective VPAC(1) agonists. Chimaeric human VPAC(2)-VPAC(1) recombinant receptors expressed in CHO cells were used to identify the receptor domains implicated in these two selective ligands recognition. The VPAC(2) preference for [R(16)]-PACAP (1 - 27) over [R(16)]-PACAP (1 - 23) did not require the receptor's NH(2)-terminus domain but involved the whole transmembrane domain. In contrast, the selectivity of [L(22)]-VIP depended only on the presence of the NH(2) terminus and EC(2) domains of the VPAC(1) receptor. The present data support the idea that in the GPCR-B family of receptors the different selective ligands require different domains for their selectivity, and that the peptides carboxyl terminal sequence (amino acids 24 - 27) folds back on the transmembrane receptor domain, close to the peptides, aminoterminus.
Van Rampelbergh
J
J
Laboratory of Biological Chemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
Juarranz
M G
MG
Perret
J
J
Bondue
A
A
Solano
R M
RM
Delporte
C
C
De Neef
P
P
Robberecht
P
P
Waelbroeck
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D016466:CHO Cells; D006224:Cricetinae; D004274:DNA, Recombinant; D006801:Humans; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011869:Radioligand Assay; D018005:Receptors, Vasoactive Intestinal Peptide / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D017386:Sequence Homology, Amino Acid; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
C495401:ADCYAP1 protein, human; D004274:DNA, Recombinant; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018005:Receptors, Vasoactive Intestinal Peptide; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D014660:Vasoactive Intestinal Peptide