Editors' ChoiceAUTOPHAGY

So Hungry I Could Eat Myself

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Science Signaling  01 Feb 2011:
Vol. 4, Issue 158, pp. ec33
DOI: 10.1126/scisignal.4158ec33

Autophagy is a process by which eukaryotic cells engulf and break down cellular components to provide new substrates for metabolism. Egan et al. (see the Perspective by Hardie) report a biochemical mechanism by which low energy stores in a cell can be linked to autophagy. The authors searched for targets of the adenosine monophosphate–activated protein kinase (AMPK), which is activated when cellular concentrations of adenosine triphosphate are depleted. AMPK was found to regulate another protein kinase, ULK1, which functions in regulation of autophagy. Cells engineered so that ULK1 could not be phosphorylated by AMPK failed to respond properly to starvation, had decreased autophagy, and were prone to starvation-induced cell death.

D. F. Egan, D. B. Shackelford, M. M. Mihaylova, S. Gelino, R. A. Kohnz, W. Mair, D. S. Vasquez, A. Joshi, D. M. Gwinn, R. Taylor, J. M. Asara, J. Fitzpatrick, A. Dillin, B. Viollet, M. Kundu, M. Hansen, R. J. Shaw, Phosphorylation of ULK1 (hATG1) by AMP-activated protein kinase connects energy sensing to mitophagy. Science 331, 456–461 (2011). [Abstract] [Full Text]

D. G. Hardie, Why starving cells eat themselves. Science 331, 410–411 (2011). [Abstract] [Full Text]