title: Paradoxical antagonism of PACAP receptor signaling by VIP in Xenopus oocytes via the type-C natriuretic peptide receptor.
abstract: Atrial natriuretic peptide (ANP) and the closely-related peptides BNP and CNP are highly conserved cardiovascular hormones. They bind to single transmembrane-spanning receptors, triggering receptor-intrinsic guanylyl cyclase activity. The "truncated" type-C natriuretic peptide receptor (NPR-C) has long been called a clearance receptor because it lacks the intracellular guanylyl cyclase domain, though data suggest it might negatively couple to adenylyl cyclase via G(i). Here we report the molecular cloning and characterization of the Xenopus laevis type-C natriuretic peptide receptor (XNPR-C). Analysis confirms the presence of a short intracellular C-terminus, as well as a high similarity to fish and mammalian NPR-C. Injection of XNPR-C mRNA into Xenopus oocytes resulted in expression of high affinity [(125)I]ANP binding sites that were competitively and completely displaced by natriuretic analogs and the unrelated neuropeptide vasoactive intestinal peptide (VIP). Measurement of cAMP levels in mRNA-injected oocytes revealed that XNPR-C is negatively coupled to adenylyl cyclase in a pertussis toxin-sensitive manner. When XNPR-C was co-expressed with PAC(1) receptors for pituitary adenylyl cyclase-activating polypeptide (PACAP), VIP and natriuretic peptides counteracted the cAMP induction by PACAP. These results suggest that VIP and natriuretic peptides can potentially modulate the action of PACAP in cells where these receptors are co-expressed.
authors.affiliation: Department of Psychiatry and Mental Retardation Research Center, The David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive, Los Angeles, CA 90095, USA.
authors.forename: V
authors.initials: V
authors.lastname: Lelièvre
authors.forename: Z
authors.initials: Z
authors.lastname: Hu
authors.forename: Y
authors.initials: Y
authors.lastname: Ioffe
authors.forename: J-Y
authors.initials: JY
authors.lastname: Byun
authors.forename: A
authors.initials: A
authors.lastname: Flores
authors.forename: A
authors.initials: A
authors.lastname: Seksenyan
authors.forename: J A
authors.initials: JA
authors.lastname: Waschek
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000235:genetics* / Q000378:metabolism*; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism* / Q000494:pharmacology; D014981:Xenopus
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide; D000262:Adenylyl Cyclases; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C