title: A site on rod G protein alpha subunit that mediates effector activation.
abstract: The heterotrimeric guanine nucleotide binding proteins (G proteins) are activated by sensory or hormone receptors. In turn, the G proteins activate effector proteins such as adenylyl cyclase, cyclic guanosine 3',5'-monophosphate phosphodiesterase (cGMP PDE), phospholipase C, and potassium and calcium ion channels by mechanisms that are poorly understood. A site on the alpha subunit of the G protein transducin (alpha t) has been identified that interacts with and activates cGMP phosphodiesterase, the effector enzyme in rod photoreceptors. A 22-amino acid peptide, corresponding to residues 293 to 314 from the COOH-terminal region of alpha t, fully mimicked alpha t and potently activated PDE. This region is adjacent to the receptor activation domain; thus, the alpha subunit of this G protein has a site for interaction with both its effector and receptor that maps near the COOH-terminus.
authors.affiliation: Department of Physiology and Biophysics, University of Illinois College of Medicine, Chicago 60680.
authors.forename: H M
authors.initials: HM
authors.lastname: Rarick
authors.forename: N O
authors.initials: NO
authors.lastname: Artemyev
authors.forename: H E
authors.initials: HE
authors.lastname: Hamm
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011487:Protein Conformation
chemical_list: D046911:Macromolecular Substances; D010446:Peptide Fragments; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D019204:GTP-Binding Proteins