FoxO1 integrates multiple metabolic pathways. Nutrient levels modulate FoxO1 acetylation, but the functional consequences of this posttranslational modification are unclear. To answer this question, we generated mice bearing alleles that encode constitutively acetylated and acetylation-defective FoxO1 proteins. Homozygosity for an allele mimicking constitutive acetylation (Foxo1 KQ/KQ) results in embryonic lethality due to cardiac and angiogenesis defects. In contrast, mice homozygous for a constitutively deacetylated Foxo1 allele (Foxo1 KR/KR) display a unique metabolic phenotype of impaired insulin action on hepatic glucose metabolism but decreased plasma lipid levels and low respiratory quotient that are consistent with a state of preferential lipid usage. Moreover, Foxo1 KR/KR mice show a dissociation between weight gain and insulin resistance in predisposing conditions (high fat diet, diabetes, and insulin receptor mutations), possibly due to decreased cytokine production in adipose tissue. Thus, acetylation inactivates FoxO1 during nutrient excess whereas deacetylation selectively potentiates FoxO1 activity, protecting against excessive catabolism during nutrient deprivation. © 2011 Elsevier Inc.
Banks, A. S., Kim-Muller, J. Y., Mastracci, T. L., Kofler, N. M., Qiang, L., Haeusler, R. A., … Accili, D. (2011). Dissociation of the glucose and lipid regulatory functions of FoxO1 by targeted knockin of acetylation-defective alleles in mice. Cell Metabolism, 14(5), 587–597. https://doi.org/10.1016/j.cmet.2011.09.012