Spatial approximation between the C-terminus of VIP and the N-terminal ectodomain of the VPAC1 receptor.
Vasoactive intestinal peptide (VIP) exerts many biological functions through interaction with the VPAC1 receptor, a class II G protein-coupled receptor. Photoaffinity labeling studies associated with receptor mapping and three-dimensional molecular modeling demonstrated that the central part of VIP (6-24) interacts with the N-terminal ectodomain of VPAC1 receptor. However, the domain of the VPAC1 receptor interacting with the C-terminus of VIP is still unknown. A photoaffinity probe, Bpa28-VIP, was synthetized by substitution of amidated Asn28 of VIP by amidated photoreactive para-benzoyl-L-Phe (Bpa). Bpa28-VIP was shown to be a hVPAC1 receptor agonist in CHO cells expressing the recombinant VPAC1 receptor. After obtaining a covalent 125I-[Bpa28-VIP]/hVPAC1 complex, it was cleaved by CNBr, PNGase F, and endopeptidase Glu-C and the cleavage products were analyzed by electrophoresis. The data demonstrated that 125I-[Bpa28-VIP] was covalently bonded to the 121-133 fragment within the N-terminal ectodomain of the receptor. This fragment is adjacent to those covalently attached to the central part (6-24) of VIP.
Ceraudo
E
E
INSERM U773, Faculté de Médecine Bichat, 16 rue Henri Huchard, 75018 Paris, France.
Tan
Y-V
YV
Couvineau
A
A
Lacapere
J-J
JJ
Laburthe
Mark
M
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D006801:Humans; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I / Q000235:genetics / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
D010446:Peptide Fragments; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D014660:Vasoactive Intestinal Peptide; D000262:Adenylyl Cyclases