Ultraviolet light-induced stimulation of the JNK mitogen-activated protein kinase in the absence of src family tyrosine kinase activation.
In T cells, the JNK mitogen-activated protein kinase is activated by simultaneous stimulation of the T-cell receptor and CD28 or by a number of stress stimuli including ultraviolet light, hydrogen peroxide, and anisomycin. Lck, a Src family kinase, is essential for T-cell receptor-mediated activation of JNK. We asked whether Lck was also involved in stress-mediated activation of JNK. JNK was activated by ultraviolet light irradiation in all of the four T-cell lines we examined, but Lck was not. Additionally, JNK activation by ultraviolet light, hydrogen peroxide, and anisomycin was completely normal in T cells lacking Lck. These data suggest that Lck is not activated by ultraviolet light irradiation, nor is it required for JNK activation in T cells by any of the stress stimuli we tested. We also examined JNK activation by ultraviolet light in mouse fibroblasts expressing no known Src kinases. The activation of JNK by ultraviolet light was completely normal in these cells. Finally, treatment of lymphoid and epithelial cells with a Src kinase family inhibitor PP2-reduced tyrosine phosphorylation of cellular proteins markedly without affecting ultraviolet light-induced activation of JNK. These results suggest that Src kinases are not essential for ultraviolet light-induced activation of JNK in a diverse variety of cell types.
Amdjadi
K
K
Molecular Biology and Virology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA. kamdjadi@aim.salk.edu
Sefton
B M
BM
D000818:Animals; D004789:Enzyme Activation / Q000528:radiation effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000528:radiation effects; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction / Q000528:radiation effects*; D014466:Ultraviolet Rays; D019061:src-Family Kinases / Q000378:metabolism*
D019061:src-Family Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases