EIF-2 kinase explained

eIF-2-alpha kinase is a kinase enzyme that phosphorylates eIF2α. There are four forms in mammals:^[1]

• EIF2AK1: heme-regulated inhibitor kinase (HRI)
• EIF2AK2: the double-stranded RNA-dependent kinase (protein kinase R, PKR)
• EIF2AK3: also known as "PKR-like endoplasmic reticulum kinase" (PEK/PERK)
• EIF2AK4: also known as GCN2

These are all responsible for the phosphorylation of the alpha subunit of eIF-2 at serine 51, one of the best-characterized mechanisms for down-regulating protein synthesis in eukaryotes as a part of cellular stress response.^[2]

Notes and References

1. Web site: Gene group HUGO Gene Nomenclature Committee . www.genenames.org.
2. Berlanga . JJ . Santoyo . J . De Haro . C . Characterization of a mammalian homolog of the GCN2 eukaryotic initiation factor 2alpha kinase. . European Journal of Biochemistry . October 1999 . 265 . 2 . 754–62 . 10.1046/j.1432-1327.1999.00780.x . 10504407.