title: Nitric oxide and differential effects of ATP on mitochondrial permeability transition.
abstract: The mitochondrial permeability transition pore (PTP) undergoes a calcium-dependent transition (MPT) that disrupts membrane potential and releases apoptogenic proteins. Because PTP opening is enhanced by oxidation of thiols at the so-called "S-site," we hypothesized that nitrogen monoxide (NO*) could enhance the open probability of the PTP, e.g., by S-nitrosylation or S-thiolation. At low NO donor concentrations (1 to 20 microM), PTP opening in succinate-energized liver mitochondria at nonlimiting calcium was delayed or unaffected, while it was accelerated by NO donors at 20 to 100 microM. At low donor concentrations, PTP opening was facilitated twofold by adenosine triphosphate (ATP), which normally delays PTP opening. Among NO donors, the oxatriazole GEA 3162, with an activation constant (Ka) of 1.9 microM at 500 microM ATP was more effective at enhancing pore transition than SIN-1 or SNAP. NO donor effects were superseded by diamide, which induces disulfide formation, but independent of SH-adduct formation by alkylation. NO-related changes in PTP function were accompanied by protein mixed disulfide formation, inhibited by dithiothreitol (DTT), and reversed by DTT after donor addition. PTP opening was stimulated in the presence of ATP by L-arginine-dependent NO production, i.e., mitochondrial NOS activity. ATP-facilitated pore opening was sensitive to atractyloside and depended on nucleotide interactions but not on hydrolysis, because specific nonhydrolyzable ATP analogs accelerated pore opening. These data indicate NO can influence pore transition by oxidation of thiols that produce conformational changes governing the ATP interaction at the adenine nucleotide transporter.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA. piant001@mc.duke.edu
authors.forename: Claude A
authors.initials: CA
authors.lastname: Piantadosi
authors.forename: Lynn G
authors.initials: LG
authors.lastname: Tatro
authors.forename: A Richard
authors.initials: AR
authors.lastname: Whorton
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008930:Mitochondria, Liver / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D000226:Mitochondrial ADP, ATP Translocases / Q000187:drug effects / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000378:metabolism / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism / Q000502:physiology*; D010084:Oxidation-Reduction / Q000187:drug effects; D010539:Permeability / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D020030:Nitric Oxide Donors; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide; D000255:Adenosine Triphosphate; D000226:Mitochondrial ADP, ATP Translocases; D019001:Nitric Oxide Synthase