Circadian clock-coordinated hepatic lipid metabolism: only transcriptional regulation?
By regulating the metabolism of fatty acids, carbohydrates, and xenobiotic, the mammalian circadian clock plays a fundamental role on the liver physiology. At present, it is supposed that the circadian clock regulates metabolism mostly by regulating the expression of liver enzymes at the transcriptional level. However, recent evidences suggest that some signaling pathways synchronized by the circadian clock can also influence metabolism at a post-transcriptional level. In this context, we have recently shown that the circadian clock synchronizes the rhythmic activation of the IRE1alpha pathway in the endoplasmic reticulum. The absence of circadian clock perturbs this secondary clock, provokes deregulation of endoplasmic reticulum-localized enzymes, and leads to impaired lipid metabolism. We will describe here the additional pathways synchronized by the clock and discussed the influence of the circadian clock-controlled feeding rhythm on them.
Gachon
Frédéric
F
Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, CH-1005, Switzerland. Frederic.Gachon@unil.ch
Bonnefont
Xavier
X
D000818:Animals; D002940:Circadian Rhythm; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004722:Endoribonucleases / Q000378:metabolism; D005247:Feeding Behavior; D005786:Gene Expression Regulation; D006801:Humans; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic
C510185:Ern1 protein, mouse; D017346:Protein Serine-Threonine Kinases; D004722:Endoribonucleases