Blocking AMPK β1 myristoylation enhances AMPK activity and protects mice from high-fat diet-induced obesity and hepatic steatosis

AMP-activated protein kinase (AMPK) is a master regulator of cellular energy homeostasis and a therapeutic target for metabolic diseases. Co/post-translational N-myristoylation of glycine-2 (Gly2) of the AMPK β subunit has been suggested to regulate the distribution of the kinase between the cytosol and membranes through a “myristoyl switch” mechanism. However, the relevance of AMPK myristoylation for metabolic signaling in cells and in vivo is unclear. Here, we generated knockin mice with a Gly2-to-alanine point mutation of AMPKβ1 (β1-G2A). We demonstrate that non-myristoylated AMPKβ1 has reduced stability but is associated with increased kinase activity and phosphorylation of the Thr172 activation site in the AMPK α subunit. Using proximity ligation assays, we show that loss of β1 myristoylation impedes colocalization of the phosphatase PPM1A/B with AMPK in cells. Mice carrying the β1-G2A mutation have improved metabolic health with reduced adiposity, hepatic lipid accumulation, and insulin resistance under conditions of high-fat diet-induced obesity. [Display omitted] •Generation of mice carrying a myristoylation-deficient G2A mutation of AMPKβ1•AMPKβ1 G2A cells have increased basal AMPKα Thr172 phosphorylation and activity•Blocking AMPKβ1 myristoylation disrupts colocalization with the phosphatase PPM1A/B•AMPKβ1 G2A mice have improved metabolic health under high-fat diet conditions Neopane et al. show that genetic loss of the AMPK β1 myristoylation site (G2A) disrupts colocalization with the phosphatase PPM1A/B. Cells expressing non-myristoylated AMPK β1-G2A have increased basal AMPK activity despite reduced stability of the β1 subunit. High-fat diet-fed AMPK β1-G2A mice have reduced liver lipid accumulation and improved insulin sensitivity.