| abstract |
C-terminal, alpha helical domain of Class Pi Glutathione S-transferases. Glutathione S-transferase (GST) C-terminal domain family, Class Pi subfamily; GSTs are cytosolic dimeric proteins involved in cellular detoxification by catalyzing the conjugation of glutathione (GSH) with a wide range of endogenous and xenobiotic alkylating agents, including carcinogens, therapeutic drugs, environmental toxins, and products of oxidative stress. The GST fold contains an N-terminal thioredoxin-fold domain and a C-terminal alpha helical domain, with an active site located in a cleft between the two domains. GSH binds to the N-terminal domain while the hydrophobic substrate occupies a pocket in the C-terminal domain. Class Pi GST is a homodimeric eukaryotic protein. The human GSTP1 is mainly found in erythrocytes, kidney, placenta and fetal liver. It is involved in stress responses and in cellular proliferation pathways as an inhibitor of JNK (c-Jun N-terminal kinase). Following oxidative stress, monomeric GSTP1 dissociates from JNK and dimerizes, losing its ability to bind JNK and causing an increase in JNK activity, thereby promoting apoptosis. GSTP1 is expressed in various tumors and is the predominant GST in a wide range of cancer cells. It has been implicated in the development of multidrug-resistant tumors. |