Abstract
Nutrients and bioenergetics are prerequisites for proliferation and survival of mammalian cells. We present evidence that the cyclin-dependent kinase inhibitor p27Kip1, 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 (p27T198A) 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.
Original language | English (US) |
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Pages (from-to) | 218-224 |
Number of pages | 7 |
Journal | Nature Cell Biology |
Volume | 9 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2007 |
Externally published | Yes |
ASJC Scopus subject areas
- Cell Biology