PERK, a Ser/Thr protein kinase, phosphorylates the alpha subunit of eukaryotic translation-initiation factor 2 (EIF2), leading to its inactivation and to a rapid reduction of translational initiation and repression of global protein synthesis. PERK serves as a critical effector of unfolded protein response (UPR)-induced G1 growth arrest due to the loss of cyclin D1. Defects in PERK are the cause of Wolcott-Rallison syndrome, an early-onset diabetes mellitus.The synthetic peptide used to raise the antibody Cat. No. 200117 is selected from a sequence within the C-term region of human PERK. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.