Rhodopsin-family receptors associate with small G proteins to activate phospholipase D

• Published in: Nature (London) 1998-03, Vol.392 (6674), p.411-414
• Main Authors: Mitchell, Rory, McCulloch, Derek, Lutz, Eve, Johnson, Melanie, MacKenzie, Chris, Fennell, Myles, Fink, George, Zhou, Wei, Sealfon, Stuart C
• Format: Article
• Language: English
• Subjects: ADP-Ribosylation Factors; Animals; Brefeldin A; COS Cells; Cyclopentanes - pharmacology; Enzyme Activation; Enzymes; Estrenes - pharmacology; GTP-Binding Proteins - antagonists & inhibitors; GTP-Binding Proteins - metabolism; Guanosine Triphosphate - analogs & derivatives; Guanosine Triphosphate - metabolism; Humanities and Social Sciences; Humans; letter; Male; multidisciplinary; Mutation; Neurology; Phospholipase D - antagonists & inhibitors; Phospholipase D - metabolism; Proteins; Pyrrolidinones - pharmacology; Rats; Receptor, Muscarinic M3; Receptors, LHRH - agonists; Receptors, LHRH - chemistry; Receptors, LHRH - genetics; Receptors, LHRH - metabolism; Receptors, Muscarinic - chemistry; Receptors, Muscarinic - metabolism; Recombinant Proteins - metabolism; rhoA GTP-Binding Protein; Rhodopsin - chemistry; Rhodopsin - metabolism; Science; Science (multidisciplinary); Tumor Cells, Cultured; Type C Phospholipases - antagonists & inhibitors; Type C Phospholipases - metabolism
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/32937

G-protein-coupled receptors of the rhodopsin family transduce many important neural and endocrine signals. These receptors activate heterotrimeric G proteins and in many cases also cause activation of phospholipase D, an enzyme that can be controlled by the small G proteins ARF and RhoA. Here we show that the activation of phospholipase D that is induced by many, but not all, Ca2+-mobilizing G-protein-coupled receptors is sensitive to inhibitors of ARF and of RhoA. Receptors of this type were co-immunoprecipitated with ARF or RhoA on exposure to agonists, and the effects of GTP analogues on ligand binding to the receptor changed to a profile that is characteristic of small G proteins. These receptors contain the amino-acid sequence AsnProXXTyr in their seventh transmembrane domain, whereas receptors capable of activating phospholipase D without involving ARF contain the sequence AspProXXTyr. Mutation of this latter sequence to AsnProXXTyr in the gonadotropin-releasing hormone receptor conferred sensitivity to an inhibitor of ARF, and the reciprocal mutation in the 5-HT2A receptor for 5-hydroxytryptamine reduced its sensitivity to the inhibitor. Receptors carrying the AsnProXXTyr motif thus seem to form functional complexes with ARF and RhoA.