Treatment of intact hepatocytes with either the phorbol ester TPA or glucagon elicits the phosphorylation and functional inactivation of the inhibitory guanine nucleotide regulatory protein Gi

FEBS Letters
N J PyneM D Houslay

Abstract

The antiserum AS7 can specifically immunoprecipitate alpha-Gi from membrane extracts as well as from a mixture of purified alpha-Gi and alpha-Go as ascertained using [32P]ADP-ribosylated G-proteins. Using this antiserum to immunoprecipitate alpha-Gi from hepatocytes labelled with 32P it was evident that alpha-Gi was phosphorylated under basal (resting) conditions. Challenge of hepatocytes with the tumour promoting phorbol ester TPA, however, elicited a marked enhancement of the phosphorylation state of alpha-Gi. This was accompanied by the loss of inhibitory effect of Gi on adenylate cyclase, as judged by the inability of low concentrations of p[NH]ppG to inhibit forskolin-stimulated adenylate cyclase activity. Such actions were mimicked by treatment of hepatocytes with either glucagon or TH-glucagon, an analogue of glucagon which is incapable of activating adenylate cyclase and elevating intracellular cyclic AMP concentrations. Pre-treatment of hepatocytes with either glucagon, TPA or insulin did not affect the ability of pertussis toxin to cause the NAD+-dependent, [32P]ADP-ribosylation of alpha-Gi in membrane fractions isolated from such pre-treated hepatocytes. We suggest that protein kinase C can elicit the phosphorylation...Continue Reading

References

Dec 15, 1978·The Biochemical Journal·S A SmithC I Pogson
Jan 1, 1987·Annual Review of Biochemistry·A G Gilman
Aug 15, 1984·The Biochemical Journal·C M HeyworthM D Houslay

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Citations

Dec 1, 1992·Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research·H M KochS Hough
Nov 1, 1993·Journal of Cellular Biochemistry·R Ravindra, J F Caro
Apr 1, 1991·Journal of Cellular Physiology·M P BosM P Herrmann-Erlee
Nov 1, 1991·Journal of Cellular Physiology·A VigneryM B Ganz
Aug 1, 1993·The International Journal of Biochemistry·M E Torres-MárquezR Moreno-Sánchez
Aug 1, 1993·Mechanisms of Ageing and Development·N Fraeyman, A van Ermen
Mar 11, 1998·Clinical and Experimental Pharmacology & Physiology·R Donnelly, X Qu
Jul 1, 1991·Acta Physiologica Scandinavica·H L VikmanJ J Ohisalo
Jul 1, 1992·The Journal of Experimental Zoology·S M DownsJ J Eppig
Sep 29, 1995·The Journal of Biological Chemistry·T A Fields, P J Casey
Mar 22, 1996·The Journal of Biological Chemistry·H PoppletonT B Patel
Feb 1, 1991·The American Journal of Physiology·S M Hernández-SotomayorJ A García-Sáinz
Jan 1, 1995·Life Sciences·C M Schramm, M M Grunstein
Jan 1, 1990·Trends in Biochemical Sciences·M D HouslayG Milligan
Jul 15, 1991·Biochemical and Biophysical Research Communications·T Pessa-MorikawaL C Andersson
Nov 30, 1989·Biochemical and Biophysical Research Communications·N J PyneM D Houslay
May 4, 1990·Science·R E Gundersen, P N Devreotes

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