title: Genetic and structural analysis of G protein alpha subunit regulatory domains.
abstract: Genetic and structural analysis of the alpha chain polypeptides of heterotrimeric G proteins defines functional domains for GTP/GDP binding, GTPase activity, effector activation, receptor contact and beta gamma subunit complex regulation. The conservation in sequence comprising the GDP/GTP binding and GTPase domains among G protein alpha subunits readily allows common mutations to be made for the design of mutant polypeptides that function as constitutive active or dominant negative alpha chains when expressed in different cell types. Organization of the effector activation, receptor and beta gamma contact domains is similar in the primary sequence of the different alpha subunit polypeptides relative to the GTP/GDP binding domain sequences. Mutation within common motifs of the different G protein alpha chain polypeptides have similar functional consequences. Thus, what has been learned with the Gs and Gi proteins and the regulation of adenylyl cyclase can be directly applied to the analysis of newly identified G proteins and their coupling to receptors and regulation of putative effector enzymes.
authors.affiliation: National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206.
authors.forename: G L
authors.initials: GL
authors.lastname: Johnson
authors.forename: N
authors.initials: N
authors.lastname: Dhanasekaran
authors.forename: S K
authors.initials: SK
authors.lastname: Gupta
authors.forename: J M
authors.initials: JM
authors.lastname: Lowndes
authors.forename: R R
authors.initials: RR
authors.lastname: Vaillancourt
authors.forename: A E
authors.initials: AE
authors.lastname: Ruoho
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000595:Amino Acid Sequence; D000242:Cyclic AMP / Q000096:biosynthesis; D019204:GTP-Binding Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid
chemical_list: D011993:Recombinant Fusion Proteins; D000246:Adenosine Diphosphate Ribose; D000242:Cyclic AMP; D019204:GTP-Binding Proteins