5563

PRKAA2

AMPK|AMPK2|AMPKa2|PRKAA;protein kinase, AMP-activated, alpha 2 catalytic subunit;PRKAA2;protein kinase, AMP-activated, alpha 2 catalytic subunit

5'-AMP-activated protein kinase catalytic subunit alpha-2|5'-AMP-activated protein kinase, catalytic alpha-2 chain|ACACA kinase|AMP-activated protein kinase alpha-2 subunit variant 2|AMP-activated protein kinase alpha-2 subunit variant 3|AMPK alpha 2|AMPK

1p31

protein-coding

AMP-activated protein kinase (AMPK) is emerging as a central cellular signaling hub involved in energy homeostasis and proliferation. The kinase is considered as a suitable target for pharmacological intervention in several energy-related pathologies like diabetes type II and cancer, although its signaling network is still incompletely understood. Here we apply an original two-dimensional in vitro screening approach for AMPK substrates that combines biophysical interaction based on surface plasmon resonance with in vitro phosphorylation. By enriching for proteins that interact with a specific AMPK isoform, we aimed to identify substrates that are also preferentially phosphorylated by this specific AMPK isoform. Application of this screen to full-length AMPK alpha2beta2gamma1 and soluble rat liver proteins identified the tumor suppressor fumarate hydratase (FH). FH was confirmed to interact with and to be preferentially phosphorylated by the AMPKalpha2 isoform by using yeast-two-hybrid and in vitro phosphorylation assays. AMPK-mediated phosphorylation of FH significantly increased enzyme activity in vitro and in vivo, suggesting that it is a bona fide AMPK substrate. In vivo, AMPKalpha2 is supposed to target the cytosolic/nuclear pools of FH, whose tumor suppressor function relies on DNA damage repair and inhibition of HIF-1alpha-signaling.