Amino acids as regulators of cell signalling

Amino acids (AA) are involved in the regulation of many intracellular biochemical pathways. This signalling role has been studied mostly in skeletal muscle, where some AA Such as leucine and citrulline, are particularly active in promoting protein synthesis. Several proteins involved in protein translation are activated by AA including a protein called mTOR. AA are also involved in the control of gene expression via an amino acid regulatory element (AARE) found in the promoter of several genes such as CHOP. The modulation of gene expression by AA is based on a complex mechanism involving a protein kinase GCN2 and the transcriptional factors ATE At a physiological level, the activation of this pathway allows, through a neural circuit, to inhibit food intake when AA composition in food is unbalanced. (C) 2008 Elsevier Masson SAS. Tous droits reserves