Function
AMP-activated protein kinase (AMPK) is a nuclear receptor which regulates cellular uptake of glucose, β-oxidation of fatty acids and biogenesis of glucose transporter thus playing a role in cellular energy homeostasis by phosphorylating key proteins. In response to low levels of ATP, AMPK activates energy-producing pathways and inhibits energy-consuming pathways.
Relevance
AMPK is an important drug target for obesity, type 2 diabetes and cancer. AMPK activity is enhanced during exercise resulting in increased glucose uptake and blood supply in muscles. Stresses like hypoglycemia, anoxia and ischemia produce increase in AMPK levels.
Structural highlights
AMPK is a heterotrimer:
is the catalytic subunit and contains .
AMPK β subunit is a scaffold on which the heterotrimer assembles. β subunit contains Ser108 (SEP)
AMPK γ subunit detects shifts in AMP:ATP ratio via its 4 cystathionine β synthase (CBS) domains. The active site binds AMP.
