Signaling pathways involved in cardiac energy metabolism.

Various signaling pathways coordinate energy metabolism and contractile function in the heart. Myocardial uptake of long-chain fatty acids largely occurs by facilitated diffusion, involving the membrane-associated protein, CD36. Glucose uptake, the rate-limiting step in glucose utilization, is mediated predominantly by the glucose transporter protein, GLUT4. Insulin and contraction-mediated AMPK signaling each are implicated in tightly regulating these myocardial 'gate-keepers' of energy balance, that is, CD36 and GLUT4. The insulin and AMPK signaling cascades are complex and their cross-talk is only beginning to be understood. Moreover, transcriptional regulation of the CD36 and GLUT4 is significantly understudied. This review focuses on recent advances on the role of these signaling pathways and transcription factors involved in the regulation of CD36 and GLUT4.