PRKAA1 (AMPK α1)

AMPK α1, encoded by PRKAA1, is the catalytic subunit of AMP-activated protein kinase, the cellular energy sensor that switches the cell from growth mode to survival mode when ATP runs low.

Function

AMPK monitors the AMP:ATP ratio. Rising AMP (falling energy charge) binds the complex’s gamma subunit and promotes phosphorylation of the alpha catalytic subunit at Thr172 by the upstream kinase LKB1 (STK11); calcium signals activate the same site through CaMKKβ. Activated AMPK then rebalances the cell’s budget: it phosphorylates TSC2 and RAPTOR to shut down mTORC1 and protein synthesis, inhibits ACC to switch from fatty-acid synthesis to oxidation, stimulates glucose uptake,