ULK1-regulated AMP sensing by AMPK and its application for the treatment of chronic kidney disease
AMP-activated protein kinase (AMPK) is a central kinase involved in energy homeostasis. Increased intracellular adenosine monophosphate (AMP) levels result in AMPK activation through the binding of AMP to the {gamma}-subunit of AMPK. Recently, we reported that AMP-induced AMPK activation is impaired in the kidneys in chronic kidney disease (CKD) despite an increase in the AMP/ATP ratio. However, the mechanisms by which AMP sensing is disrupted in CKD are unclear. In this study, we identified mechanisms of energy homeostasis in which Unc-51-like kinase 1 (ULK1)-dependent phosphorylation of AMPK{gamma}1 at Ser260/Thr262 promotes AMP sensitivity of AMPK. AMPK activation by AMP was impaired in Ulk1-/- mice despite an increased AMP/ATP ratio. We also demonstrated that MK8722, an allosteric AMPK activator, activates AMPK in the kidneys of a CKD mouse model via a pathway that is independent of AMP sensing. MK8722 treatment significantly attenuates the deterioration of renal function in CKD and is a potential therapeutic option in CKD therapeutics.