|| Checking for direct PDF access through Ovid
The ultraviolet B (UVB) component of sunlight can cause severe damage to skin cells and even induce skin cancer. Growing evidence indicates that the UVB-induced signaling network is complex and involves diverse cellular processes. In this study, we investigated the role of c-Jun NH2-terminal kinase-associated leucine zipper protein (JLP), a scaffold protein for mitogen-activated protein kinase (MAPK) signaling cascades, in UVB-induced apoptosis. We found that UVB-induced skin epidermal apoptosis was prevented inJlpknockout (KO) as well as in keratinocyte-specificJlpKO mice. Analysis of the repair of UVB-induced DNA damage over time showed no evidence for the involvement of JLP in this process. In contrast, UVB-stimulated p38 MAPK activation in the skin was impaired in bothJlpKO and keratinocyte-specificJlpKO mice. Moreover, topical treatment of UVB-irradiated mouse skin with a p38 inhibitor significantly suppressed the epidermal apoptosis in wild-type mice, but not inJlpKO mice. Our findings suggest that JLP in skin basal keratinocytes plays an important role in UVB-induced apoptosis by modulating p38 MAPK signaling pathways. This is the first study to show a critical role for JLP in anin vivoresponse to environmental stimulation.