Eukaryotic translation initiation factor 2-alpha kinase 3 (EIF2AK3)

Metabolic-stress sensing protein kinase which phosphorylates the alpha subunit of eukaryotic translation initiation factor 2 (eIF-2-alpha/EIF2S1) on'Ser-52' through the unfolded protein response (UPR) and in response to reduced amino acid availability. Converts phosphorylated eIF-2-alpha/EIF2S1 either in a global protein synthesis inhibitor, resulting in a reduced overall use of amino acids, or to a translation initiation activator of specific mRNAs, like the transcriptional activator ATF4, and hence allowing ATF4-mediated reprogramming of amino acid biosynthetic gene expression to alleviate nutrient depletion.

Serves as a critical effector of unfolded protein response (UPR)- induced G1 growth arrest due to the loss of cyclin-D1 (CCND1). Involved in control of mitochondrial morphology and function.