Gi2 mediates alpha 2-adrenergic inhibition of adenylyl cyclase in platelet membranes: in situ identification with G alpha C-terminal antibodies.

Simonds, William F.; Goldsmith, Paul K.; Codina, Juan; Unson, Cecilia G.; Spiegel, Allen M.

doi:10.1073/pnas.86.20.7809

Cited by 342 publications

(203 citation statements)

References 38 publications

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“…Identification of the signal transduction pathway mediating tolerance/dependence is hampered by the ability of ORs to activate multiple inhibitory G proteins and intracellular effector systems (Gudermann et al 1992). Several experimental approaches have been employed to elucidate the specificity of signal transduction cascades in situ, such as application of site-directed anti-G protein antibodies (Simonds et al 1989), antisense strategies (Kleuss et al 1991), and over-expression of genetically modified PTXresistant inhibitory G a subunits (Leaney et al 2000). However, each of these approaches failed to define specific inhibitory AC signalling pathways most likely because of a pronounced functional redundancy between inhibitory G a subunits (Tang et al 1991;Sunahara et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Identity of adenylyl cyclase isoform determines the G protein mediating chronic opioid‐induced adenylyl cyclase supersensitivity

Ammer¹,

Christ²

2002

Journal of Neurochemistry

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To determine the intracellular signal transduction pathway responsible for the development of tolerance/dependence, the ability of G z a to substitute for pertussis toxin (PTX)-sensitive G proteins in mediating adenylyl cyclase (AC) supersensitivity was examined in the presence of defined AC isoforms. In transiently l-opioid receptor (OR) transfected COS-7 cells (endogenous inhibitory G proteins: G i a2, G i a3 and G z a), neither acute (1 lmol/L) nor chronic morphine treatment (1 lmol/L; 18 h) influenced intracellular cAMP production. Coexpression of the l-OR together with AC type V and VI fully restored the ability of morphine to acutely inhibit cAMP generation. Chronic morphine treatment further resulted in the development of tolerance/dependence, as assessed by desensitization of the acute inhibitory opioid effect (tolerance) as well as the induction of AC supersensitivity after drug withdrawal (dependence). Specific direction of l-OR signalling via G z a by both PTX treatment and G z a over-expression had no effect on chronic morphine regulation of AC type V, but completely abolished the development of tolerance/dependence with AC type VI. Similar results were obtained in stably l-OR-expressing HEK293 cells transiently cotransfected with G z a and either AC type V or VI. Coprecipitation studies further verified that G z a specifically binds to AC type V but not type VI. Taken together, these results demonstrate that in principle each of the OR-activated G proteins per se is able to mediate AC supersensitivity. However, they also indicate that it is the molecular nature of AC isoform that selects and determines the OR-activated G protein mediating tolerance/dependence.

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Section: Discussionmentioning

confidence: 99%

Identity of adenylyl cyclase isoform determines the G protein mediating chronic opioid‐induced adenylyl cyclase supersensitivity

Ammer¹,

Christ²

2002

Journal of Neurochemistry

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“…Gs antisera ('RM' and 'CSl') were obtained in rabbit after repeated immunization with a conjugate of Keyhole Limpets Hemocyanin and a synthetic peptide corresponding to the RMHLRQYELL C-terminal sequence of GSa [23,34]. 100 gg membrane proteins were separated on a 10% or 12.5% SDS-PAGE [21] and transferred to nitrocellulose membranes.…”

Section: Immunoblotting With Gscr Antiserummentioning

confidence: 99%

“…Cell membranes (5 mg/ml) were extracted with 1% Na-cholate and Gsol activity in the extract was evaluated by its ability to complement the Gscr deficiency of S49 cyc-membranes in vitro [17,22,23]. The Nacholate extract from CTr cells (100 ~1) was added to cyc-membranes (100 kg) and incubated at 30°C for 20 min with GTP (100 PM); CTs cell membranes were used as a control.…”

Section: Gsol Functional Assaymentioning

confidence: 99%

Reduction of adenylyl cyclase activity by cholera toxin in myeloid cells

1990

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In IPC-81 cells, the adenylyl-cyclase activation by cholera toxin produces an elevation of CAMP that causes a rapid cytolysis. A resistant clone with deficient cholera toxin-induced cyclase activity (yet sensitive to CAMP) showed a rapid decrease in the amount of membrane-bound Gsa (4247 kDa) detectable soon after ADP-ribosylation of these proteins; pertussis toxin-sensitive G proteins (41 kDa) were not affected. Resistant cells showed a rapid decrease of Gsa that is consistent with the finding that CAMP did not accumulate in these cells. Cholera toxin treatment of resistant cells had long-lasting effects (several weeks) on the level of Gsa in the cell membrane. The duration of Gsa decrease does not correspond to the probable life of catalytically active cholera toxin in the cells, and suggests a regulated process more complex than a proteolytic degradation targeted on ADP-ribosylated molecules.

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“…Several pertussis-toxin substrates ranging from 39 to 41 kDa have also been discovered by cDNA cloning (Suki et al, 1987;Jones & Reed, 1987): three of these have been classified as Gsa, and one as Go. Immunodetection with specific antibodies has allowed the identification of these proteins in various tissues and shows a tissue-selective expression of the various forms (Goldsmith et al, 1987(Goldsmith et al, , 1988Mitchell et al, 1989;Simonds et al, 1989). The exact function of the individual pertussis-toxin substrates is not yet known with certainty, but G. is thought to be involved in the mediation of Ca2+-channel activity (Goldsmith et al, 1988), G,a3 is able to regulate K+ channels (Codina et al, 1988) and G1a2 mediates the a2-adrenergic inhibition of AC (Simonds et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

Levels of G-proteins in liver and brain of lean and obese (ob/ob) mice

McFarlane-Anderson

Bailly

Bégin–Heick

1992

Biochemical Journal

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G-protein levels were assessed in liver and brain membranes of lean and obese mice. ADP-ribosylation and immunodetection studies revealed a decrease in the abundance of G8 and G, a-subunits in the liver membranes of obese mice compared with lean mice. In contrast, in brain membranes, the abundance of these proteins was not significantly different between lean and obese mice. Studies at the mRNA level in both liver and brain revealed no difference in gene expression between lean and obese mice. Protein and mRNA studies both showed that G., Gial, Gia2, Goa and G,? subunits are present in brain membranes, and Gia3 is barely detectable. In liver, G,a, Gia2 and G/J subunits are the major constituents, whereas Gial, G1a3 and Goa are barely detectable. It is possible that the differences observed at the protein level are due to different rates of translation of the mRNA. Different rates of release of the a-subunits from the membrane and/or different rates of degradation would also explain these results.

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Gi2 mediates alpha 2-adrenergic inhibition of adenylyl cyclase in platelet membranes: in situ identification with G alpha C-terminal antibodies.

Abstract: A panel of antibodies to synthetic decapeptides corresponding to the C termini of guanine nucleotidebinding regulatory protein (G protein) a subunits has been generated in rabbits.

Cited by 342 publications

References 38 publications

Identity of adenylyl cyclase isoform determines the G protein mediating chronic opioid‐induced adenylyl cyclase supersensitivity

Identity of adenylyl cyclase isoform determines the G protein mediating chronic opioid‐induced adenylyl cyclase supersensitivity

Reduction of adenylyl cyclase activity by cholera toxin in myeloid cells

Levels of G-proteins in liver and brain of lean and obese (ob/ob) mice

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