Effect of age and oxidative stress on tyrosine phosphorylation of ZAP-70
| Autor: | George N. Abraham, Bulbul Chakravarti |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Senescence
Adult Cellular immunity medicine.medical_specialty Aging CD3 Complex T-Lymphocytes Oxidative phosphorylation Biology medicine.disease_cause Oxidative Phosphorylation chemistry.chemical_compound Internal medicine medicine Humans Tyrosine Cells Cultured Aged chemistry.chemical_classification Reactive oxygen species ZAP-70 Protein-Tyrosine Kinase Antibodies Monoclonal Tyrosine phosphorylation Protein-Tyrosine Kinases Oxidative Stress Endocrinology chemistry Signal transduction Oxidative stress Developmental Biology |
| Zdroj: | Mechanisms of ageing and development. 123(4) |
| ISSN: | 0047-6374 |
| Popis: | Oxidative stress is believed to be one of the leading contributors to the aging process and loss of cellular function with aging. Although, several age-associated phenomena have been correlated with reactive oxygen species, the role of oxidative stress in the age-related decline of T-cell activity is not yet clear. The present study was carried out to determine the effect of reactive oxygen species on tyrosine phosphorylation of ZAP-70, a key enzyme in the T-cell signal transduction pathway. Our previous as well as present studies have demonstrated an age-related down-regulation of tyrosine phosphorylation of ZAP-70 following activation of freshly isolated T cells with various stimulating agents. Currently, we observe that under mild and chronic oxidative stress, tyrosine phosphorylation of ZAP-70 is impaired following stimulation of the T cells with anti-CD3 antibody. Interestingly, in contrast to our observation using freshly isolated T cells, there is no age-associated impairment of tyrosine phosphorylation of ZAP-70 when T cells, cultured for 2 days in a serum-free medium in the presence or in the absence of oxidative stress, are stimulated with anti-CD3 antibody. The current observation suggests that the age-associated down-regulation of tyrosine phosphorylation of ZAP-70 is not an intrinsic defect inherent of the T cells due to aging and is reversible. We also observed that under oxidative stress in vitro, there was no significant difference in inhibition of tyrosine phosphorylation of ZAP-70 in T cells isolated from elderly and young donors. Finally, it was also noted that the down-regulation of tyrosine phosphorylation of ZAP-70 under oxidative stress in young and elderly donors was not due to impairment in the net expression of ZAP-70 under oxidative stress thereby suggesting that dysregulation in the balance of kinase-phosphatase activities under oxidative stress might have been implicated in the observed phenomenon. |
| Databáze: | OpenAIRE |
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