Sterol-regulatory-element-binding protein Ic mediates insulin action on hepatic gene expression

Effects of insulin on the expression of liver-specific genes are part of th e adaptive mechanisms aimed at maintaining energy homeostasis in mammals. W hen the diet is rich in carbohydrates, secreted insulin stimulates the expr ession of genes for enzymes involved in glucose utilization (glucokinase, L -type pyruvate kinase and lipogenic enzymes) and inhibits genes for enzymes involved in glucose production (phosphenolpyruvate carboxykinase). The mec hanisms by which insulin controls the expression of these genes have been p oorly understood. Recently, the transcription factor sterol-regulatory-elem ent-binding protein 1c has been proposed as a key mediator of insulin trans criptional effects. Here we review the evidence that has led to this propos al and the consequences for our understanding of insulin effects in physiol ogical or pathological conditions.