The eIF-2 alpha kinases: regulators of protein synthesis in starvation and stress.
Phosphorylation of translation initiation factor 2 alpha is a highly conserved mechanism for down-regulating protein synthesis in response to starvation or stress. The yeast eIF-2 alpha kinase GCN2 is stimulated by deprivation for amino acids or purines. In addition to inhibiting general protein synthesis, GCN2 specifically stimulates translation of GCN4, a transcriptional activator of amino acid biosynthetic genes. HRI is an eIF-2 alpha kinase that is activated in rabbit reticulocytes by heme-deprivation and stress conditions that elicit the heat-shock response. The eIF-2 alpha kinase DAI is activated by double-stranded RNA during viral infections and is an important component of the interferon response. DAI has also been implicated as a tumor suppressor. These protein kinases provide an important means of coupling the rate of protein synthesis and cell division to environmental conditions.
Hinnebusch
A G
AG
Section on Molecular Genetics of Lower Eukaryotes, National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.
D000818:Animals; D006801:Humans; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011817:Rabbits; D013217:Starvation / Q000378:metabolism*; D013312:Stress, Physiological / Q000378:metabolism*; D019892:eIF-2 Kinase
D017346:Protein Serine-Threonine Kinases; D019892:eIF-2 Kinase