New connections in the regulation of PEPCK gene expression by insulin [and discussion]

Calum Sutherland, Richard M. O'Brien, Daryl K. Granner, J. Saklatvala, P. Cohen, M. F. White

    Research output: Contribution to journalArticle

    62 Citations (Scopus)

    Abstract

    Phosphoenolpyruvate carboxykinase (PEPCK) catalyses the rate-limiting step in hepatic gluconeogenesis. Glucagon (via the second messenger cAMP) and glucocorticoids stimulate transcription of the PEPCK gene whereas insulin and phorbol esters have a dominant inhibitory effect. Wortmannin, an inhibitor of 1-phosphatidylinositol 3-kinase (PI 3-kinase), blocks the inhibition of glucocorticoid- and cAMP-stimulated PEPCK gene transcription by insulin. By contrast, although phorbol esters mimic the action of insulin on the regulation of PEPCK gene transcription, wortmannin does not block the effect of these agents. Thus PI 3-kinase is required for the regulation of PEPCK gene expression by insulin but not by phorbol esters. In liver cells, insulin administration stimulates the activity of multiple protein kinases, including the p42/p44 Mitogen Activated Protein (MAP) kinase and the p70/p85 ribosomal protein S6 kinase. Selective inhibition of the activation of either kinase, utilizing the compounds PD98059 and rapamycin respectively, does not affect insulin regulation of PEPCK gene transcription. Thus regulation of PEPCK gene transcription requires PI 3-kinase but does not require the activation of either p42/p44 MAP kinase or p70/p85 ribosomal protein S6 kinase.

    Original languageEnglish
    Pages (from-to)191-199
    Number of pages9
    JournalPhilosophical Transactions of the Royal Society B - Biological Sciences
    Volume351
    Issue number1336
    DOIs
    Publication statusPublished - 29 Feb 1996

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