Paraquat Inhibits the Processing of Human Manganese-Dependent Superoxide Dismutase by SF-9 Insect Cell Mitochondria

Reichenbecher, V E; Green, T.; Wright, Gary L.; Wang, S.

doi:10.1006/excr.1997.3579

Cited by 20 publications

(16 citation statements)

References 14 publications

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“…However, another explanation for this discrepancy might be that the h mt TrpRS was expressed in insect cells and not in human cells. It is possible that there is a difference in the mitochondrial localization process between the two cell types, although earlier results from expression of mitochondrial proteins in the baculovirus expression system have indicated a tendency for correct processing (41)(42)(43). Therefore, it is likely that the mitochondrial import mechanisms in human and insect cells are closely related and that the signal peptide of h mt TrpRS expressed in human cells is identical to the signal peptide observed in insect cells.…”

Section: The Effect Of Interferon On Expression Of H Mt Trprs-tomentioning

confidence: 98%

Identification and Characterization of Human Mitochondrial Tryptophanyl-tRNA Synthetase

Jørgensen

Soegaard

Rossing

et al. 2000

Journal of Biological Chemistry

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Section: The Effect Of Interferon On Expression Of H Mt Trprs-tomentioning

confidence: 98%

Identification and Characterization of Human Mitochondrial Tryptophanyl-tRNA Synthetase

Jørgensen

Soegaard

Rossing

et al. 2000

Journal of Biological Chemistry

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“…Oxidative stress-mediated regulation of mitochondrial processing of MnSOD Mitochondrial processing of human precursor MnSOD was shown to be compromised by superoxide generating compound paraquat (186), which is a redox-cycling agent that transfers electrons to molecular oxygen to form superoxide (54). It has been demonstrated that the mitochondrial processing of human MnSOD from precursor to the mature form was inhibited by paraquat treatment.…”

Section: Mitochondrial Import/processing Of Mnsodmentioning

confidence: 99%

“…This, in turn, resulted in lower MnSOD activity. The mechanism of paraquat-mediated inhibition is not known; however, it is suggested that paraquat induces a specific lesion in the MnSOD processing machinery (186). It is believed that paraquat treatment leads to oxidation of critical sulfhydryl groups (cysteine [Cys] residues) of the proteins of the mitochondrial import machinery (185).…”

Section: Mitochondrial Import/processing Of Mnsodmentioning

confidence: 99%

MnSOD in Oxidative Stress Response-Potential RegulationviaMitochondrial Protein Influx

Candas

2014

Antioxidants & Redox Signaling

274

178

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Significance: The mitochondrial antioxidant manganese superoxide dismutase (MnSOD) is encoded by genomic DNA and its dismutase function is fully activated in the mitochondria to detoxify free radical O 2 -generated by mitochondrial respiration. Accumulating evidence shows an extensive communication between the mitochondria and cytoplasm under oxidative stress. Not only is the MnSOD gene upregulated by oxidative stress, but MnSOD activity can be enhanced via the mitochondrial protein influx (MPI). Recent Advances: A cluster of MPI containing cytoplasmic/nuclear proteins, such as cyclins, cyclin-dependent kinases, and p53 interact with and alter MnSOD activity. These proteins modulate MnSOD superoxide scavenging activity via post-translational modifications in the mitochondria. In addition to well-established pathways in gene expression, recent findings suggest that MnSOD enzymatic activity can also be enhanced by phosphorylation of specific motifs in mitochondria. This review attempts to discuss the pre-and post-translational regulation of MnSOD, and how these modifications alter MnSOD activity, which induces a cell adaptive response to oxidative stress. Critical Issues: MnSOD is biologically significant to aerobic cells. Its role in protecting the cells against the deleterious effects of reactive oxygen species is evident. However, the exact network of MnSOD-associated cellular adaptive reaction to oxidative stress and its post-translational modifications, especially its enzymatic enhancement via phosphorylation, is not yet fully understood. Future Directions: The broad discussion of the multiple aspects of MnSOD regulation, including gene expression, protein modifications, and enzymatic activity, will shed light onto the unknown mechanisms that govern the prosurvival networks involved in cellular and mitochondrial adaptive response to genotoxic environment. Antioxid. Redox Signal. 20, 1599Signal. 20, -1617

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“…Hsp's also enhance import efficiency because the Tom70 import receptor of the translocase of the mitochondrial outer membrane contains specific docking sites for Hsp90 and Hsc70 chaperones (72,73). Oxidative stress impairs mitochondrial import and processing of SOD2 (74), and improved mitochondria import caused by increased HSP90 expression may represent a mechanism that helps to protect mitochondria from injury by facilitating uptake of antioxidant proteins into the mitochondrial compartment. Import is also crucial to replace damaged mitochondrial proteins and to support mitochondrial biogenesis during tissue regeneration.…”

Section: Effects Of Ischemic Preconditioning On Heat Shock Proteinsmentioning

confidence: 99%

Ischemic Preconditioning Prevents Free Radical Production and Mitochondrial Depolarization in Small-for-Size Rat Liver Grafts

Rehman

Connor²,

Ramshesh³

et al. 2008

Transplantation

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Background. Ischemic preconditioning (IP) renders tissues more tolerant to subsequent longer episodes of ischemia. This study tested whether IP attenuates injury of small-for-size liver grafts by preventing free radical production and mitochondrial dysfunction. Methods. IP was induced by clamping the portal vein and hepatic artery for 9 min. Livers were harvested 5 min after releasing the clamp. Mitochondrial polarization and cell death were assessed by intravital confocal/multiphoton microscopy of rhodamine 123 (Rh123) and propidium iodide. Free radicals were trapped with ␣-(4-pyridyl 1-oxide)-Ntert-butylnitrone and measured using electron spin resonance. Results. After quarter-size liver transplantation, alanine aminotransferase, serum bilirubin, necrosis, and apoptosis all increased. IP blocked these increases by more than 58%. 5-Bromo-2Ј-deoxyuridine labeling and increases of graft weight were only ϳ3% and 0.2% in quarter-size grafts without IP, respectively, but increased to 32% and 60% in ischemic-preconditioned grafts, indicating better liver regeneration. Eighteen hours after implantation, viable cells with depolarized mitochondria in quarter-size grafts were 15 per high power field, and dead cells were less than 1 per high power field, indicating that depolarization preceded necrosis. A free radical adduct signal was detected in bile from quarter-size grafts. IP decreased this free radical formation and prevented mitochondrial depolarization. IP did not increase heat shock proteins 10,27,32,60,70,72, 75 and Cu/Zn-superoxide dismutase (SOD) but increased heat shock protein-90, a chaperone that facilitates protein import into mitochondria, and mitochondrial Mn-SOD. Conclusion. Taken together, IP decreases injury and improves regeneration of small-for-size liver grafts, possibly by increasing mitochondrial Mn-SOD, thus protecting against free radical production and mitochondrial dysfunction.

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Paraquat Inhibits the Processing of Human Manganese-Dependent Superoxide Dismutase by SF-9 Insect Cell Mitochondria

Cited by 20 publications

References 14 publications

Identification and Characterization of Human Mitochondrial Tryptophanyl-tRNA Synthetase

Identification and Characterization of Human Mitochondrial Tryptophanyl-tRNA Synthetase

MnSOD in Oxidative Stress Response-Potential RegulationviaMitochondrial Protein Influx

Ischemic Preconditioning Prevents Free Radical Production and Mitochondrial Depolarization in Small-for-Size Rat Liver Grafts

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