Sangwon Kang

Mammalian tissues express three immunologically distinct peroxiredoxin (Prx) proteins (Prx I, II, and III), which are the products of distinct genes. With the use of recombinant proteins Prx I, II, and III, all have now been shown to possess peroxidase activity and to rely on Trx as a source of reducing equivalents for the reduction of H2O2. Prx I and II are cytosolic proteins, whereas Prx III is localized in mitochondria. Transient overexpression of Prx I or II in cultured cells showed that the

A new type of peroxidase enzyme, named thioredoxin peroxidase (TPx), that reduces H2O2 with the use of electrons from thioredoxin and contains two essential cysteines was recently identified. TPx homologs, termed peroxiredoxin (Prx), have also been identified and include several proteins, designated 1-Cys Prx, that contain only one conserved cysteine. Recombinant human 1-Cys Prx expressed in and purified from Escherichia coli has now been shown to reduce H2O2 with electrons provided by dithiothr

Cytoplasmic presence of Hsp60, which is principally a nuclear gene-encoded mitochondrial chaperonin, has frequently been stated, but its role in intracellular signaling is largely unknown. In this study, we demonstrate that the cytosolic Hsp60 promotes the TNF-alpha-mediated activation of the IKK/NF-kappaB survival pathway via direct interaction with IKKalpha/beta in the cytoplasm. Selective loss or blockade of cytosolic Hsp60 by specific antisense oligonucleotide or neutralizing antibody dimini

Shear stress plays a significant role in endothelial cell biology and atherosclerosis development. Previous work by our group has shown that fluid flow stimulates important functional changes in cells through protein expression regulation. Peroxiredoxins (PRX) are a family of antioxidant enzymes but have yet to be investigated in response to shear stress. Studies have shown that oscillatory shear stress (OS) increases reactive oxygen species (ROS) levels in endothelial cells, whereas laminar she

Tumor necrosis factor-α (TNF-α) induces the activation of all three types of mitogen-activated protein kinase (MAPK): c-Jun NH2-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK). This cytokine also induces the production of several types of reactive oxygen species, including H2O2. With the use both of HeLa cells expressing wild-type or dominant negative forms of the cytosolic peroxidase peroxiredoxin II and of mouse embryonic fibroblasts deficient in this protein, we ev

Mammalian 2-Cys peroxiredoxin (Prx) enzymes are overexpressed in most cancer tissues, but their specific signaling role in cancer progression is poorly understood. Here we demonstrate that Prx type II (PrxII) plays a tumor-promoting role in colorectal cancer by interacting with a poly(ADP-ribose) polymerase (PARP) tankyrase. PrxII deletion in mice with inactivating mutation of adenomatous polyposis coli (APC) gene reduces intestinal adenomatous polyposis via Axin/β-catenin axis and thereby promo

The 2-Cys peroxiredoxins (Prx) belong to a family of antioxidant enzymes that detoxify reactive oxygen and nitrogen species and are distributed throughout the intracellular and extracellular compartments. However, the presence and role of 2-Cys Prxs in the nucleus have not been studied. This study demonstrates that the PrxII located in the nucleus protects cancer cells from DNA damage-induced cell death. Although the two cytosolic 2-Cys Prxs, PrxI and PrxII, were found in the nucleus, only PrxII

In normal cells, the cellular reactive oxygenspecies (ROS) level is proportional to the activity ofmitochondrial electron transport and tightly controlled byendogenous antioxidant system. However, energy metabolismand ROS homeostasis in cancer cells are much differentfrom those in normal cells. For example, a majorityof cellular glucose is metabolized through aerobic glycolysis(‘‘Warburg effect’’) and the pentose phosphate pathway. Cancer cells harbor functional mitochondria, butmany mutations i

Mammalian cells have a well-defined set of antioxidant enzymes, which includes superoxide dismutases, catalase, glutathione peroxidases, and peroxiredoxins. Peroxiredoxins are the most recently identified family of antioxidant enzymes that catalyze the reduction reaction of peroxides, such as H2O2. In particular, typical 2-Cys peroxiredoxins are the featured peroxidase enzymes that receive the electrons from NADPH by coupling with thioredoxin and thioredoxin reductase. These enzymes distribute t