Peroxiredoxin 4 is copiously expressed inheart, liver andpancreas as well as inblood,leukocyte and brain wherein it is mainly localized within theendoplasmic reticulum but also present inlysosome, nucleus and cytosol. It contains peroxidatic and resolving cysteine separated by 121 amino acids.
Peroxiredoxin 4 regulates the activation of NF-kappa-B in the cytosol through inflection of I-kappa-B-alpha phosphorylation. It plays a significant role in the redox balance in the ER in which the cysteine residue is first oxidized to sulfonic acid to form intermolecular disulfide bond with another peroxiredoxin molecule which is reversed by the reducing activity of thioredoxin reductase system. When it is under oxidative stress conditions it undergo further oxidation to sulfonic acid reduced by sulfiredoxin however, when it is hyper-oxidized it loses its antioxidant property and only function as chaperone to assist protein folding.
Peroxiredoxin 4 is implicated in tumor progression and metastasis in lung cancer in which it is expresses at about 1.5 fold higher in tumor cells most frequently in adenocarcinoma. It is involved in the alteration rate of tumor progression and metastasis designated by anchorage independent colony formation, cell migration and invasion in lung cancer cells.
Gene name: PRDX4
Protein name: Peroxiredoxin-4