Dynamic regulation of insulin signaling and metabolic gene expression is critical to nutrient homeostasis; dysregulation of these pathways is widely implicated in insulin resistance and other disease states. Though the metabolic effects of insulin are well established, the components linking insulin signal transduction to a metabolic response are not as well understood. Here, we show that Cdc2-like kinase 2 (Clk2) is an insulin-regulated suppressor of hepatic gluconeogenesis and glucose output. Clk2 protein levels and kinase activity are induced as part of the hepatic refeeding response by the insulin/Akt pathway. Clk2 directly phosphorylates the SR domain on PGC-1α, resulting in repression of gluconeogenic gene expression and hepatic glucose output. In addition, Clk2 is downregulated in db/db mice, and reintroduction of Clk2 largely corrects glycemia. Thus, we have identified a role for and regulation of the Clk2 kinase as a component of hepatic insulin signaling and glucose metabolism.
► During refeeding, hepatic insulin signaling induces Clk2 ► Clk2 phosphorylates the PGC-1α SR domain, repressing PGC-1α activity ► Clk2 suppresses hepatic gluconeogenesis in vitro and in vivo ► Diabetic db/db mice show reduced Clk2; Clk2 expression corrects hyperglycemia
