RAPID ACTIVATION OF JNK1 IN UV-B IRRADIATED EPIDERMAL-KERATINOCYTES

Jun N-terminal kinase (JNK1) is a member of a family of stress-activat ed protein kinases which are activated by many forms of stress includi ng UV radiation, resulting in the phosphorylation of c-Jun, ATF-2, Elk -1 and p53, As UV-B radiation is mainly responsible for ultraviolet (U V)-induced skin cancers, we chose to elucidate JNK1 activation in kera tinocytes, which represent a UV-relevant system, We have demonstrated rapid activation of JNK1 in a keratinocyte cell Line, C50, in response to multiple doses of UV-B irradiation, JNK1 activation occurred withi n 1 min, peaked by 10 min and returned to near basal levels within 2 h following the UV-B treatments, Our data provide the first evidence to show that keratinocytes do respond to multiple doses of the physiolog ically relevant UV-B radiation through rapid activation of the JNK1 pa thway.