PDK1 controls upstream PI3K expression and PIP3 generation

A.M. Dieterle, P. Böhler, H. Keppeler, S. Alers, N. Berleth, S. Drießen, N. Hieke, S. Pietkiewicz, A.S. Löffler, C. Peter, A. Gray, N. R. Leslie, H. Shinohara, T. Kurosaki, M. Engelke, J. Wienands, M. Bonin, S. Wesselborg, B. Stork (Lead / Corresponding author)

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)

    Abstract

    The PI3K/PDK1/Akt signaling axis is centrally involved in cellular homeostasis and controls cell growth and proliferation. Due to its key function as regulator of cell survival and metabolism, the dysregulation of this pathway is manifested in several human pathologies including cancers and immunological diseases. Thus, current therapeutic strategies target the components of this signaling cascade. In recent years, numerous feedback loops have been identified that attenuate PI3K/PDK1/Akt-dependent signaling. Here, we report the identification of an additional level of feedback regulation that depends on the negative transcriptional control of phosphatidylinositol 3-kinase (PI3K) class IA subunits. Genetic deletion of 3-phosphoinositide-dependent protein kinase 1 (PDK1) or the pharmacological inhibition of its downstream effectors, that is, Akt and mammalian target of rapamycin (mTOR), relieves this suppression and leads to the upregulation of PI3K subunits, resulting in enhanced generation of phosphatidylinositol-3,4,5-trisphosphate (PIP). Apparently, this transcriptional induction is mediated by the concerted action of different transcription factor families, including the transcription factors cAMP-responsive element-binding protein and forkhead box O. Collectively, we propose that PDK1 functions as a cellular sensor that balances basal PIP generation at levels sufficient for survival but below a threshold being harmful to the cell. Our study suggests that the efficiency of therapies targeting the aberrantly activated PI3K/PDK1/Akt pathway might be increased by the parallel blockade of feedback circuits.Oncogene advance online publication, 29 July 2013; doi:10.1038/onc.2013.266.
    Original languageEnglish
    Pages (from-to)3043-3053
    Number of pages11
    JournalOncogene
    Volume33
    Issue number23
    DOIs
    Publication statusPublished - 5 Jun 2014

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