TY - JOUR
T1 - A truncated form of RGS3 negatively regulates G protein-coupled receptor stimulation of adenylyl cyclase and phosphoinositide phospholipase C
AU - Chatterjee, Tapan K.
AU - Eapen, Alex K.
AU - Fisher, Rory A.
PY - 1997/6/13
Y1 - 1997/6/13
N2 - Identification of a new family of proteins (RGS proteins) that function as negative regulators of G protein signaling has sparked new understanding of desensitization of this signaling process. Recent studies with several mammalian RGS proteins has delineated their ability to interact with and function as GTPase-activating proteins specifically for G proteins in the G(i) family. Here, we investigated the functional activity of RGS3 and a truncated form of RGS3 on G protein-coupled receptor-mediated activation of adenylyl cyclase, phosphoinositide phospholipase C, and mitogen-activated protein kinase in intact cells. Polymerase chain reaction and 5'-rapid amplification of cDNA ends analyses revealed the tissue-specific expression of a short form of the RGS3 transcript that encodes the approximate carboxyl- terminal half of RGS3. This truncated form of RGS3 (RGS3T) was shown recently to function as a negative regulator of pheromone signaling in yeast (Druey, K. M., Blumer, K. J., Kang, V. R., and Kehrl, J. H. (1996) Nature 379, 742- 746). Baby hamster kidney cells transiently transfected with RGS3T cDNA exhibited a pronounced impairment in platelet-activating factor receptor- stimulated inositol phosphate production, a pertussis toxin-insensitive response. Similarly, calcitonin gone-related peptide receptor-stimulated increases in intracellular cAMP and pituitary adenylate-cyclase activating polypeptide receptor-stimulated increases in both cAMP and inositol phosphates were reduced significantly in RGS3T transfectants compared with vector-transfected control cells. In contrast, baby hamster kidney cells transfected with the full-length RGS3 cDNA showed no impairment in cAMP and inositol phosphate production mediated by these G protein-coupled receptors. However, lysophosphatidic acid receptor-stimulated phosphorylation of endogenous ERK1 and ERK2 was impaired markedly in both RGS3 and RGS3T transfectants, demonstrating the functional ability of both RGS forms to modulate G(i)-mediated signaling. These results provide the first evidence for regulatory effects of an RGS protein on G(s)- and G(q)-mediated signaling in intact cells and document that the carboxyl-terminal region of RGS3 comprises the structural domain for this activity.
AB - Identification of a new family of proteins (RGS proteins) that function as negative regulators of G protein signaling has sparked new understanding of desensitization of this signaling process. Recent studies with several mammalian RGS proteins has delineated their ability to interact with and function as GTPase-activating proteins specifically for G proteins in the G(i) family. Here, we investigated the functional activity of RGS3 and a truncated form of RGS3 on G protein-coupled receptor-mediated activation of adenylyl cyclase, phosphoinositide phospholipase C, and mitogen-activated protein kinase in intact cells. Polymerase chain reaction and 5'-rapid amplification of cDNA ends analyses revealed the tissue-specific expression of a short form of the RGS3 transcript that encodes the approximate carboxyl- terminal half of RGS3. This truncated form of RGS3 (RGS3T) was shown recently to function as a negative regulator of pheromone signaling in yeast (Druey, K. M., Blumer, K. J., Kang, V. R., and Kehrl, J. H. (1996) Nature 379, 742- 746). Baby hamster kidney cells transiently transfected with RGS3T cDNA exhibited a pronounced impairment in platelet-activating factor receptor- stimulated inositol phosphate production, a pertussis toxin-insensitive response. Similarly, calcitonin gone-related peptide receptor-stimulated increases in intracellular cAMP and pituitary adenylate-cyclase activating polypeptide receptor-stimulated increases in both cAMP and inositol phosphates were reduced significantly in RGS3T transfectants compared with vector-transfected control cells. In contrast, baby hamster kidney cells transfected with the full-length RGS3 cDNA showed no impairment in cAMP and inositol phosphate production mediated by these G protein-coupled receptors. However, lysophosphatidic acid receptor-stimulated phosphorylation of endogenous ERK1 and ERK2 was impaired markedly in both RGS3 and RGS3T transfectants, demonstrating the functional ability of both RGS forms to modulate G(i)-mediated signaling. These results provide the first evidence for regulatory effects of an RGS protein on G(s)- and G(q)-mediated signaling in intact cells and document that the carboxyl-terminal region of RGS3 comprises the structural domain for this activity.
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U2 - 10.1074/jbc.272.24.15481
DO - 10.1074/jbc.272.24.15481
M3 - Article
C2 - 9182581
AN - SCOPUS:0031006273
SN - 0021-9258
VL - 272
SP - 15481
EP - 15487
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 24
ER -