Overexpression of G(s)alpha in NG108-15, neuroblastomaXglioma cells: effects on receptor regulation of the stimulatory adenylyl cyclase cascade.
NeuroblastomaXglioma hybrid, NG108-15 cells were stably transfected with an epitope tagged variant of G(s)alpha (HA-G(s)alpha). The introduced HA-G(s)alpha was able to interact with the IP prostanoid receptor and was able to stimulate adenylyl cyclase activity as measured by an enhanced capacity of membrane extracts to reconstitute NaF-dependent adenylyl cyclase activity to membranes of S49 lymphoma cyc- cells. Despite this, neither the maximal stimulation nor the potency of agonist ligands at the IP prostanoid, A2 adenosine or secretin receptors was altered substantially compared to the parental cells although the basal adenylyl cyclase activity was increased. These data indicate that cellular levels of G(s)alpha do not limit signal transduction capacity in NG108-15 cells, whereas enhanced expression of adenylyl cyclase allows greater maximal cAMP generation following receptor activation (MacEwan, D.J., Kim, G.D. and Milligan, G. (1996) Biochem. J. 318, 1033-1039).
Mullaney
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Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, UK.
Carr
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Milligan
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D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism*; D006822:Hybrid Cells; D016285:Iloprost / Q000494:pharmacology; D008024:Ligands; D051379:Mice; D058906:Purinergic P1 Receptor Agonists; D051381:Rats; D043562:Receptors, G-Protein-Coupled; D011964:Receptors, Gastrointestinal Hormone / Q000819:agonists / Q000378:metabolism; D011982:Receptors, Prostaglandin / Q000819:agonists / Q000378:metabolism*; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D012633:Secretin / Q000494:pharmacology; D015398:Signal Transduction; D014162:Transfection; D014407:Tumor Cells, Cultured
D008024:Ligands; D058906:Purinergic P1 Receptor Agonists; D043562:Receptors, G-Protein-Coupled; D011964:Receptors, Gastrointestinal Hormone; D011982:Receptors, Prostaglandin; D018047:Receptors, Purinergic P1; C029937:secretin receptor; D012633:Secretin; D019830:Adenosine-5'-(N-ethylcarboxamide); D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases; D016285:Iloprost; D000241:Adenosine