ULTRAVIOLET-A INDUCES ACTIVATION OF AP-1 IN CULTURED HUMAN KERATINOCYTES

UV-A irradiation induces a time-dependent activation of AP-1 in NCTC 2 544 human keratinocytes, 4 h after irradiation, a 2-3-fold increase in AP-1 activity is observed in human keratinocytes and fibroblasts, Act ivation is still detectable 24 h later, The UV-A induced AP-1 binding complex is shown to contain c-Fos and c-Jun proteins, Lipophilic vitam in E impedes UV-A induced lipid peroxidation but does not prevent AP-1 activation,which is inhibited by N-acetylcysteine, a hydrophilic anti oxidant, This finding suggests that UV-A-dependent AP-1 activation is sensitive to the cellular redox state but is not related to membrane l ipid peroxidation.