EIF2α is a 65-kD protein that catalyzes the formation of puromycin-sensitive 80S preinitiation complexes. eIF2α, also known as EIF2S1 or EIF2, is a 315 amino acid subunit of the eukaryotic initiation complex that functions to bind tRNA to the 40S ribosomal subunit (in a GTP-dependent manner), thereby initiating translation. Phosphorylation of the eukaryotic initiation factor 2 (eIF2) α subunit is a well-documented mechanism to downregulate protein synthesis under a variety of stress conditions.When eIF2αis not phosphorylated, translation occurs at a normal rate. However, upon phosphorylation by one of several kinases, eIF2αis stabilized, thus preventing the GDP/GTP exchange reaction and slowing translation.
