Drosophila stimulatory G protein alpha subunit activates mammalian adenylyl cyclase but interacts poorly with mammalian receptors: implications for receptor-G protein interaction.
Heterotrimeric guanine nucleotide binding proteins (G proteins) transduce signals from cell-surface receptors to intracellular effector proteins. Two forms of stimulatory G protein (Gs) alpha-like subunit have been described in Drosophila melanogaster. To examine the function of these subunits we have used vaccinia virus vectors to express both proteins in cyc- cells, a murine S49 cell line deficient for Gs alpha activity. Receptor-independent activation of each Drosophila Gs alpha has demonstrated that both forms are capable of activating mammalian adenylyl cyclase and thus have the activity expected of stimulatory G proteins. However, the Drosophila Gs alpha subunits interact poorly with mammalian Gs-coupled receptors. These observations have helped to identify a region of high variability in Gs alpha proteins that may be important for receptor interactions.
Quan
F
F
Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201.
Thomas
L
L
Forte
M
M
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D016375:Antisense Elements (Genetics); D001483:Base Sequence; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D003001:Cloning, Molecular; D004330:Drosophila / Q000378:metabolism*; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005822:Genetic Vectors; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011956:Receptors, Cell Surface / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D014616:Vaccinia virus / Q000235:genetics
D016375:Antisense Elements (Genetics); D046911:Macromolecular Substances; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D002772:Cholera Toxin; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases