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RGS proteins constitute a newly appreciated group of negative regulators of G protein signaling. Discovered by genetic screens in yeast, worms, and other organisms, two mammalian RGS proteins, RGS4 and GAIP, act as GTPase-activating proteins for members of the Gi family of G protein alpha subunits. We have purified recombinant RGS4 to homogeneity and(More)
Signaling pathways that link extracellular factors to activation of the monomeric guanosine triphosphatase (GTPase) Rho control cytoskeletal rearrangements and cell growth. Heterotrimeric guanine nucleotide-binding proteins (G proteins) participate in several of these pathways, although their mechanisms are unclear. The GTPase activities of two G protein(More)
  • Gary L Waldo, Tiffany K Ricks, +8 authors T Kendall Harden
  • 2010
Transmembrane signals initiated by a broad range of extracellular stimuli converge on nodes that regulate phospholipase C (PLC)-dependent inositol lipid hydrolysis for signal propagation. We describe how heterotrimeric guanine nucleotide-binding proteins (G proteins) activate PLC-βs and in turn are deactivated by these downstream effectors. The 2.7-angstrom(More)
Members of the regulators of G protein signaling (RGS) family stimulate the intrinsic guanosine triphosphatase (GTPase) activity of the alpha subunits of certain heterotrimeric guanine nucleotide-binding proteins (G proteins). The guanine nucleotide exchange factor (GEF) for Rho, p115 RhoGEF, has an amino-terminal region with similarity to RGS proteins.(More)
RGS proteins constitute a newly appreciated and large group of negative regulators of G protein signaling. Four members of the RGS family act as GTPase-activating proteins (GAPs) with apparent specificity for members of the Gi alpha subfamily of G protein subunits. We demonstrate here that two RGS proteins, RGS4 and GAIP, also act as GAPs for Gq alpha, the(More)
A method is described for purification of G protein alpha and beta gamma subunits from Sf9 cells infected with recombinant baculoviruses. The subunit to be purified is coexpressed with an associated subunit bearing a hexahistidine tag. After adsorption of the oligomer to a Ni(2+)-containing column, the subunit to be purified is eluted specifically by(More)
Members of the Gq alpha subfamily of heterotrimeric guanine nucleotide-binding proteins (G proteins) activate phospholipase C (PLC). The complementary DNAs (cDNAs) for the G protein alpha subunits Gq alpha and G11 alpha were expressed in insect (Sf9) cells using recombinant baculovirus. Active, nonaggregated, and membrane-associated protein was generated(More)
G protein-coupled receptor kinases (GRKs) are well characterized regulators of G protein-coupled receptors, whereas regulators of G protein signaling (RGS) proteins directly control the activity of G protein alpha subunits. Interestingly, a recent report (Siderovski, D. P., Hessel, A., Chung, S., Mak, T. W., and Tyers, M. (1996) Curr. Biol. 6, 211-212)(More)
Heterotrimeric G proteins, composed of alpha and betagamma subunits, forward signals from transmembrane receptors to intracellular effector enzymes and ion channels. Free betagamma activates downstream targets, but its action is terminated by association with GDP-liganded alpha subunits. Because alpha can inhibit activation of many effectors by betagamma,(More)