Gsalpha contains an unidentified covalent modification that increases its affinity for adenylyl cyclase.
Many G protein alpha subunits are dually acylated with myristate and palmitate or are palmitoylated on more than one cysteine residue near their N termini. The Galpha protein that activates adenylyl cyclase, alphas, is not myristoylated but can be reversibly palmitoylated. It appears that alphas contains another, as-yet-unidentified covalent modification that decreases its apparent dissociation constant for adenylyl cyclase from 50 nM to <0. 5 nM. This modification is at or near the N terminus of the protein and is hydrophobic. Palmitoylation of native alphas does not account for its high affinity for adenylyl cyclase.
Kleuss
C
C
Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235, USA.
Gilman
A G
AG
D000262:Adenylyl Cyclases / Q000378:metabolism*; D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002417:Cattle; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D018076:DNA, Complementary; D004789:Enzyme Activation; D005091:Exons; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D016324:Sequence Tagged Sites; D018411:Spodoptera; D014162:Transfection
D018076:DNA, Complementary; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases