Dynamic regulation of insulin signaling and metabolic gene expression is critical to nutrient homeostasis; dysregulation of these pathways is usually widely implicated in insulin resistance and other disease says. insulin signaling and glucose metabolism. Introduction Hepatic gluconeogenesis the net production of glucose from substrate molecules is critical for adaptation to fasting conditions and contributes to hyperglycemia in diabetes (Biddinger and Kahn 2006 Pilkis and Granner 1992 Quinn and Yeagley 2005 In the fed state insulin normalizes blood glucose levels by increasing glucose uptake in peripheral tissues GW4064 and by suppressing gluconeogenesis in the liver. While the metabolic effects of insulin have been studied for decades a mechanistic understanding of insulin transmission transduction is just recently coming into focus. In the SCC1 liver most of insulin’s metabolic effects are through activation of Insulin receptor PI3K and Akt pathways. Akt GW4064 can directly suppress hepatic gluconeogenesis by negatively regulating the gluconeogenic transcriptional regulators: Foxo1 PGC-1α and CRTC2 (also known as TORC2) (Dentin et al. 2007 Li et al. 2007 Matsumoto et al. 2007 Nakae et al. 2001 Puigserver et al. 2003 The PGC-1α transcriptional coactivator is an important mediator of hepatic fasting rate of metabolism PGC-1α induces and maintains manifestation of the gluconeogenic gene system during fasted claims responding to glucagon/cAMP through CRTC2 (Herzig et al. 2001 Koo et al. 2005 Rhee et al. 2003 Yoon et al. 2001 During the fed state insulin/Akt can suppress PGC-1α activity through several mechanisms. Akt can directly phosphorylate S570 in PGC-1α’s SR (serine-arginine) website (Li et al. 2007 In addition the PGC-1α SR website interacts with Foxo1 in an insulin/Akt dependent manner (Puigserver et al. 2003 These studies suggest that the PGC-1α SR website functions as an insulin-responsive website to control its gluconeogenic function. The Cdc2-like kinases (Clk) also termed LAMMER kinases are an evolutionary conserved family of dual-specificity CMGC kinases found in most if not all eukaryotes. They may be putative high-level regulators of alternate splicing through phosphorylation of SR domains on splicing factors (Colwill et al. 1996 Duncan et al. 1995 Hanes et al. 1994 Hillman et al. 2004 Lee et al. 1996 Prasad et GW4064 al. 1999 However right now there is an extremely limited understanding of Clk focuses on function and rules inside a biological context. Here we display that a member of the Clk kinases Clk2 is definitely controlled by feeding/fasting cycles in the liver. In the refed state hepatic Clk2 is definitely GW4064 induced by insulin/Akt signaling where Clk2 then phosphorylates the SR website on PGC-1α. Clk2 phosphorylation of PGC-1α causes potent repression of gluconeogenic gene manifestation and hepatic glucose output that leads to hypoglycemia. Results Feeding and insulin/Akt regulate Clk2 We while others have previously found that the SR website is an insulin responsive region of PGC-1α (Li et al. 2007 Puigserver et al. 2003 In splicing factors hyper-phosphorylation of SR areas can modulate their function and activity (Prasad et al. 1999 In order to investigate the signalling and transcriptional metabolic effects of the feeding/insulin response we hypothesized the Clk kinases responsible for SR website phosphorylation in splicing factors may be involved in PGC-1α feeding/insulin rules. Among the Clk kinases tested we recognized Clk2 as being regulated by nutritional status. Clk2 protein had low large quantity in mouse liver extracts following 24hrs of fasting however Clk2 protein was strongly induced after 4 hours of refeeding and remained elevated at longer refeeding time points (Number 1A). Clk2 protein levels were also controlled in gastrocnemius muscle mass and in the heart by fasting/feeding albeit less dramatically (Supplemental Number 1A). Unlike the rules of many classic feeding/fasting genes which happens in the transcriptional level stable state Clk2 mRNA levels were mainly unchanged (Number 1B). Notably induction of Clk2 protein correlated with suppression of Pepck and PGC-1α gene manifestation. Number 1 Clk2 is definitely regulated by feeding/fasting and insulin Since elevation of serum insulin during refeeding is definitely a major stimulator of the hepatic refed rate of metabolism we tested whether insulin was.