Figure 6.

The dual role of AMPK activity in maintaining energy homeostasis and ensuring nutrient sufficiency for cell cycle progression. Upon activation by decreased ATP availability, AMPK acts to inhibit energy consuming pathways such as cholesterol and fatty acid synthesis (Hardie and Pan, 2002), whilst also increasing the activity of cell cycle inhibitors p27 and p53 (Isakovic et al., 2007). This tumor suppression acts to restore energy homeostasis by inhibiting cell cycle progression, resulting in decreased AMPK activity and a switch from catabolism to anabolism for completion of the cell cycle. AMPK thereby acts to maintain energy homeostasis and ensure nutrient sufficiency for cell cycle progression.