29th Annual Meeting of the American Society of Photobiology

Downtown Marriot

Chicago, Il.

p53 protein and p21WAF inhibitor protein co-associate with Jun amino terminal kinase (JNK1)

Abstract-
Exposure of mammalian cells to ultraviolet (UV) light and other DNA-damaging agents results in activation of the Jun amino terminal kinase/Stress-activated protein kinase pathway (JNK/SAPK), and induction of cell cycle regulatory proteins such as p53 and p21WAF. Previous studies in our laboratory have demonstrated that the basal level of JNK1 activity is modulated by the presence of wildtype or mutant p53 protein in the A1-5 rat fibroblast cell line. This cell line contains a temperature sensitive p53 allele, which allows us to regulate the relative level of wildtype and mutant p53 proteins produced in these cells. The purpose of this study was to determine whether protein-protein interactions exist between the p53, p21WAF and JNK1 proteins in A1-5 cells. We hypothesize that this interaction modulates the signal transduction response of cells to UV irradiation. To test this hypothesis, we immunoprecipitated JNK1 protein, and ran the immune complex on 12% SDS polyacrylamide gel. Immunoblot analysis demonstrated that p53 and p21WAF proteins were co-immunoprecipitated with JNK1 protein. Our results confirm that protein-protein interactions between JNK1, p53 and p21WAF proteins exist. Furthermore our studies demonstrate that both wildtype and mutant forms of p53 protein are able to interact with JNK1. These results suggest that the modulation of JNK1 activity occurs through protein-protein interactions between JNK1, p53 and p21WAF proteins.

Keywords: JNK1, p53, p21, protein interaction