Table 1.

eIF2α kinases of various eukaryotic organisms

Kinase	Yeast	C. elegans	Mammal	Stresses
HRI (EIF2AK1)	○		○	Heme levels, oxidative stress [51, 52]
PKR (EIF2AK2)			○	ds RNA [53]
PERK (EIF2AK3)		○	○	ER stress, hypoxia [54, 55]
GCN2 (EIF2AK4)	○	○	○	Amino acid starvation, UV irradiation, ROS [56–58]

The eIF2α kinases and their activating stresses are depicted for yeasts, C. elegans, and mammals