HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bell, J. D. Articles by Brunton, L. L. Search for Related Content PubMed PubMed Citation Articles by Bell, J. D. Articles by Brunton, L. L. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 261, Issue 26, 12036-12041, 09, 1986

Enhancement of adenylate cyclase activity in S49 lymphoma cells by phorbol esters. Withdrawal of GTP-dependent inhibition [published erratum appears in J Biol Chem 1986 Nov 5;261(31):14857]

JD Bell and LL Brunton

12-O-Tetradecanoylphorbol-13-acetate (TPA) enhances the apparent maximal velocity of adenylate cyclase in S49 lymphoma cells, an effect that seems not to result from an increased rate of activation of the catalytic subunit by the stimulatory GTP-binding protein (Gs) (Bell, J. D., Buxton, I. L. O., and Brunton, L. L. (1985) J. Biol. Chem. 260, 2625-2628). In membranes from wild type S49 cells, this enhancing effect of TPA is largely GTP-dependent; TPA enhances forskolin- stimulated adenylate cyclase activity by 35% in the presence of guanine nucleotide but only slightly (approximately 10%) in its absence. TPA causes comparable results in membranes from the cyc- variant that lacks the GTP-binding subunit of Gs. Blockade of the activity of the inhibitory GTP-binding protein (Gi) by high concentrations of Mg2+ (100 mM) or Mn2+ (3 mM) abolishes the effect of TPA to enhance adenylate cyclase activity in wild type membranes. The potentiation by TPA of cAMP accumulation in intact cells is greater than and not additive with the similar effect of pertussis toxin (an agent known to abolish hormonal inhibition of adenylate cyclase). Kinetic experiments indicate that TPA decreases the rate of activation of Gi by guanine nucleotide. We conclude that the resultant withdrawal of tonic inhibition of adenylate cyclase is one mechanism by which phorbol esters enhance guanine nucleotide-dependent cAMP synthesis.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				S. E. Mau, T. Sarmark, and H. Vilhardt Cross-Talk Between Cellular Signaling Pathways Activated by Substance P and Vasoactive Intestinal Peptide in Rat Lactotroph-Enriched Pituitary Cell Cultures Endocrinology, April 1, 1997; 138(4): 1704 - 1711. [Abstract] [Full Text] [PDF]