Article

Liang J, Shao SH, Xu ZX, Hennessy B, Ding Z, Larrea M et al.. The energy sensing LKB1-AMPK pathway regulates p27(kip1) phosphorylation mediating the decision to enter autophagy or apoptosis. Nat Cell Biol 9: 218-224

Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
Nature Cell Biology (Impact Factor: 19.68). 03/2007; 9(2):218-24. DOI: 10.1038/ncb1537
Source: PubMed

ABSTRACT

Nutrients and bioenergetics are prerequisites for proliferation and survival of mammalian cells. We present evidence that the cyclin-dependent kinase inhibitor p27(Kip1), is phosphorylated at Thr 198 downstream of the Peutz-Jeghers syndrome protein-AMP-activated protein kinase (LKB1-AMPK) energy-sensing pathway, thereby increasing p27 stability and directly linking sensing of nutrient concentration and bioenergetics to cell-cycle progression. Ectopic expression of wild-type and phosphomimetic Thr 198 to Asp 198 (T198D), but not unstable Thr 198 to Ala 198 (p27(T198A)) is sufficient to induce autophagy. Under stress conditions that activate the LKB1-AMPK pathway with subsequent induction of autophagy, p27 knockdown results in apoptosis. Thus LKB1-AMPK pathway-dependent phosphorylation of p27 at Thr 198 stabilizes p27 and permits cells to survive growth factor withdrawal and metabolic stress through autophagy. This may contribute to tumour-cell survival under conditions of growth factor deprivation, disrupted nutrient and energy metabolism, or during stress of chemotherapy.

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Available from: Dan Dumont, Sep 14, 2015
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