[Cellular stress and eIF-2alpha kinase].

The alpha subunit of eukaryotic initiation factor -2 (eIF-2alpha) is a molecule related to the first step of protein synthesis initiation in eukaryotes. eIF-2alpha is phosphorylated in response to a wide variety of stimuli, including viral infection, starvation, ischemia, and heat shock. Four mammalian eIF-2alpha kinases have been reported: PKR (double-stranded RNA dependent protein kinase), HRI (heme-regulated inhibitor), GCN2 (general control non-derepressible 2), and PERK (PKR-like endoplasmic reticulum kinase). Each kinase contains unique domains that recognize a different cellular stress and transmits the signals to eIF-2alpha. Hence, eIF-2alpha is considered to be a key molecule in integrated stress response. Understanding eIF-2alpha as a component of the integrated stress response may be helpful in revealing stress sitmulus and the responses to stress at the cellular level. This knowledge will contribute to the development of preventive and therapeutic approaches to stress mediated diseases.