title: The role of a membrane-bound glutathione transferase in the peroxynitrite-induced mitochondrial permeability transition pore: formation of a disulfide-linked protein complex.
abstract: We have previously shown that the mitochondrial membrane-bound glutathione transferase (mtMGST1) is activated via thiol modifications and contributes to the mitochondrial permeability transition (MPT) pore. In the present study we aimed to confirm the role of mtMGST1 in the oxidant peroxynitrite (PON)-induced MPT pore opening. PON induced the swelling of mitoplasts (inner membranes including the matrix) as well as of the mitochondria. The swelling was markedly suppressed by ADP [an adenine nucleotide translocator (ANT) ligand] and partially suppressed by cyclosporin A or by GST inhibitors (tannic acid, S-hexylglutathione). Dithiothreitol (DTT), a disulfide bond-reducing reagent, prevented the swelling. Western blot analyses of mitoplast proteins after PON-induced swelling positively identified the high molecular weight protein (HMP) including mtMGST1 (monomer), ANT (48kDa), and cyclophilin D (CypD, 30kDa). The HMP level was decreased according to suppression of the swelling and undetectable after DTT treatment. The HMP formation and swelling were also suppressed by a Ca(2+) chelating agent and antioxidants. These results suggest that the HMP is a disulfide-linked protein complex involving mtMGST1, ANT, CypD and function as a MPT pore in PON-induced swelling, in which the Ca(2+) released by PON might play an important role in the complex formation.
authors: Laboratory of Molecular Genetics and Pharmacology, School of Health Sciences, University of the Ryukyus, Uehara, Nishihara, Okinawa, Japan. imaizumi@med.u-ryukyu.ac.jp
authors: Naoki
authors: N
authors: Imaizumi
authors: Yoko
authors: Y
authors: Aniya
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D004220:Disulfides / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000378:metabolism; D008933:Mitochondrial Swelling / Q000187:drug effects / Q000502:physiology; D008970:Molecular Weight; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D018384:Oxidative Stress; D030421:Peroxynitrous Acid / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D004220:Disulfides; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins; D046912:Multiprotein Complexes; D030421:Peroxynitrous Acid; D005982:Glutathione Transferase