1. UVA irradiation induces L-isoaspartyl formation in melanoma cell proteins
- Author
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Stefania D'Angelo, Marcello Zappia, Diego Ingrosso, Maria Antonietta Tufano, Adone Baroni, Brunella Perfetto, Lucia Lubrano Lobianco, Patrizia Galletti, D’Angelo, S, Ingrosso, Diego, Perfetto, Brunella, Baroni, Adone, Zappia, M, LOBIANCO LUBRANO, L, Tufano, Ma, and Galletti, P.
- Subjects
Ultraviolet Rays ,Free radicals ,DNA Fragmentation ,medicine.disease_cause ,Nitric Oxide ,Biochemistry ,Lipid peroxidation ,chemistry.chemical_compound ,Physiology (medical) ,Oxidative damage ,Protein D-Aspartate-L-Isoaspartate Methyltransferase ,medicine ,TBARS ,Tumor Cells, Cultured ,Animals ,Humans ,UVA radiation ,Protein Methyltransferases ,Melanoma cells ,Protein deamidation ,Deamidation ,Melanoma ,chemistry.chemical_classification ,Reactive oxygen species ,Aspartic Acid ,Isoaspartyl methylation ,DNA, Neoplasm ,Neoplasm Proteins ,Rats ,Isoaspartyl methylation, Melanoma cells, Oxidative damage, Protein deamidation, Protein repair, UVA radiation, Free radicals ,Protein repair ,Enzyme ,chemistry ,DNA fragmentation ,sense organs ,Reactive Oxygen Species ,Oxidative stress ,DNA Damage - Abstract
It has been reported that UVA effects are partly mediated by production of reactive oxygen species. Moreover, oxidative stress increases protein damage, involving the occurrence of isoaspartyl residues, a product of protein deamidation/isomerization reactions. This work was undertaken in order to study the effects of UVA irradiation, mediated by oxidation, on sensitive protein targets. Melanoma cells exposed to UVA rays have been chosen as a model for monitoring the occurrence of L-isoaspartyl sites. A dramatic increase of these abnormal residues, specifically recognized and methylated by the enzyme L-isoaspartate(D-aspartate) O-methyltransferase (PCMT; EC 2.1.1.77), can be detected after exposure of M14 cells to raising doses of UVA. The effect of UVA on NO and TBARS accumulation, as well as on DNA fragmentation, has also been investigated. NO formation parallels the increase in isoaspartyl formation, while lipid peroxidation occurs only at the highest UVA doses. No DNA fragmentation has been detected under the employed experimental conditions. These results, as a whole, indicate that protein damages are one of the early events on UVA-induced cell injury. The endogenous activity of PCMT remains remarkably stable under UVA treatment, suggesting that this enzyme might play a crucial role in the repair and/or disposal of damaged proteins in UVA-irradiated cells.
- Published
- 2001