Editors' ChoiceMetabolism

Ramping Up AMPK

Science Signaling  21 Jun 2011:
Vol. 4, Issue 178, pp. ec174
DOI: 10.1126/scisignal.4178ec174

The adenosine monophosphate (AMP)–activated protein kinase (AMPK) senses depletion of energy stores (the accumulation of AMP) and activates appropriate metabolic responses to control cellular and organismal energy balance. But its name does not tell the whole story. The energy status of a cell is reflected in the “adenylate charge” or ratio of the concentration of adenosine triphosphate (ATP) to those of adenosine diphosphate (ADP) and AMP. Oakhill et al. (see the Perspective by Bland and Birnbaum) show that activity of AMPK is also highly sensitive to the concentration of ADP, as well as that of AMP. Like AMP, ADP bound to AMPK and promoted its activating phosphorylation by other protein kinases. ADP also inhibited dephosphorylation of AMPK, which inactivates the kinase. Because AMP can be rapidly deaminated in cells, sensing of ADP, as well as AMP, may be critical for the control of AMPK, which regulates a broad spectrum of biological responses from metabolism and metabolic diseases to the growth of cancer.

J. S. Oakhill, R. Steel, Z.-P. Chen, J. W. Scott, N. Ling, S. Tam, B. E. Kemp, AMPK is a direct adenylate charge-regulated protein kinase. Science 332, 1433–1435 (2011). [Abstract] [Full Text]

M. L. Bland, M. J. Birnbaum, ADaPting to energetic stress. Science 332, 1387–1388 (2011). [Abstract] [Full Text]

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