title: G(i-1)/G(i-2)-dependent signaling by single-transmembrane natriuretic peptide clearance receptor.
abstract: Single-transmembrane natriuretic peptide clearance receptor (NPR-C), which is devoid of a cytoplasmic guanylyl cyclase domain, interacts with pertussis toxin (PTx)-sensitive G proteins to activate endothelial nitric oxide synthase (eNOS) expressed in gastrointestinal smooth muscle cells. We examined the ability of NPR-C to activate other effector enzymes in eNOS-deficient tenia coli smooth muscle cells; these cells expressed NPR-C and NPR-B but not NPR-A. Atrial natriuretic peptide (ANP), the selective NPR-C ligand cANP-(4-23), and vasoactive intestinal peptide (VIP) inhibited (125)I-ANP and (125)I-VIP binding to muscle membranes in a pattern indicating high-affinity binding to NPR-C. Interaction of VIP with NPR-C was confirmed by its ability to inhibit (125)I-ANP binding to membranes of NPR-C-transfected COS-1 cells. In tenia muscle cells, all ligands selectively activated G(i-1) and G(i-2); VIP also activated G(s) via VIP(2) receptors. All ligands stimulated phosphoinositide hydrolysis, which was inhibited by ANP-(1-11), PTx, and antibodies to phospholipase C-beta3 (PLC-beta3) and Gbeta. cANP-(4-23) contracted tenia muscle cells; contraction was blocked by U-73122 and PTx and by antibodies to PLC-beta3 and Gbeta in intact and permeabilized muscle cells, respectively. VIP and ANP contracted muscle cells only after inhibition of cAMP- and cGMP-dependent protein kinases. ANP and cANP-(4-23) inhibited forskolin-stimulated cAMP in a PTx-sensitive fashion. We conclude that NPR-C is coupled to activation of PLC-beta3 via betagamma-subunits of G(i-1) and G(i-2) and to inhibition of adenylyl cyclase via alpha-subunits.
authors.affiliation: Department of Physiology and Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia 23298-0711, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Murthy
authors.forename: B Q
authors.initials: BQ
authors.lastname: Teng
authors.forename: H
authors.initials: H
authors.lastname: Zhou
authors.forename: J G
authors.initials: JG
authors.lastname: Jin
authors.forename: J R
authors.initials: JR
authors.lastname: Grider
authors.forename: G M
authors.initials: GM
authors.lastname: Makhlouf
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003106:Colon / Q000166:cytology / Q000378:metabolism; D004789:Enzyme Activation; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000502:physiology; D006162:Guanylate Cyclase; D006168:Guinea Pigs; D007527:Isoenzymes / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism; D045283:Natriuretic Agents / Q000494:pharmacology; D054799:Phospholipase C beta; D017461:Receptors, Atrial Natriuretic Factor / Q000819:agonists / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism; D000099242:Atrial Natriuretic Factor Receptor B
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D009320:Atrial Natriuretic Factor; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D019204:GTP-Binding Proteins; D006162:Guanylate Cyclase; D007527:Isoenzymes; D045283:Natriuretic Agents; D054799:Phospholipase C beta; D017461:Receptors, Atrial Natriuretic Factor; D010738:Type C Phospholipases; D014660:Vasoactive Intestinal Peptide; D000099242:Atrial Natriuretic Factor Receptor B; C073616:atrial natriuretic factor receptor C