FastScan^™ Total GCN2 ELISA Kit #96050

Phosphorylation of the eukaryotic initiation factor 2 (eIF2) alpha subunit is a well-documented mechanism of downregulating protein synthesis under a variety of stress conditions. Kinases activated by viral infection (PKR), endoplasmic reticulum stress (PERK/PEK), amino acid deprivation (GCN2), and hemin deficiency (HRI) can phosphorylate the eIF2 alpha subunit (1,2). GCN2 is also required for UV light-induced translation inhibition, and in vivo phosphorylation of murine GCN2 at Thr898 is induced by both UV irradiation and by leucine deprivation (3). UV-induced activation of NF-κB also requires GCN2, which may act simply by preventing translation of IκB-alpha to replace pools that have been ubiquitinated and degraded (4). Interestingly, proteasome inhibitors (MG132 and ALLN) activate the GCN2/eIF2alpha pathway, suggesting a pivotal role for this kinase in stress response and ubiquitin-mediated signaling (5). In vitro autophosphorylation of yeast GCN2 within its activation loop at Thr882 and Thr887 (Thr898 and Thr903 in mouse) has also been reported (6).