Molecular cloning and functional characterization of a human VIP receptor from SUP-T1 lymphoblasts.

We have cloned and sequenced a cDNA isolated from a human SUP-T1 lymphoblast cell line library. It encoded a 457 amino acids protein having 87% identity with the rat PACAP type II, VIP2 receptor. Chinese hamster ovary (CHO) cells stably transfected with cloned cDNA expressed a specific binding of 125I[Acetyl-His1]PACAP-27. This binding was inhibited by GTP, and by the peptides helodermin, VIP, PACAP-27 and PACAP-38 that also stimulated adenylate cyclase activity. The order of potency was PACAP-38 > VIP > or = helodermin > or = PACAP-27. Comparison of the results in two cell lines expressing different receptor densities suggested that helodermin and PACAP-38 had a higher intrinsic activity than VIP and PACAP-27.