Article

Uncharged tRNA and sensing of amino acid deficiency in mammalian piriform cortex.

School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California, Davis, CA 95616, USA.
Science (impact factor: 31.2). 04/2005; 307(5716):1776-8. DOI:10.1126/science.1104882 pp.1776-8
Source: PubMed

ABSTRACT Recognizing a deficiency of indispensable amino acids (IAAs) for protein synthesis is vital for dietary selection in metazoans, including humans. Cells in the brain's anterior piriform cortex (APC) are sensitive to IAA deficiency, signaling diet rejection and foraging for complementary IAA sources, but the mechanism is unknown. Here we report that the mechanism for recognizing IAA-deficient foods follows the conserved general control (GC) system, wherein uncharged transfer RNA induces phosphorylation of eukaryotic initiation factor 2 (eIF2) via the GC nonderepressing 2 (GCN2) kinase. Thus, a basic mechanism of nutritional stress management functions in mammalian brain to guide food selection for survival.

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Keywords

brain's anterior piriform cortex
 
conserved general control
 
dietary selection
 
eukaryotic initiation factor 2
 
GCN2
 
guide food selection
 
IAA deficiency
 
indispensable amino acids
 
metazoans
 
nutritional stress management functions
 
signaling diet rejection
 
wherein uncharged transfer RNA induces phosphorylation