Differential involvement of p38 mitogen-activated protein kinase kinases MKK3 and MKK6 in T-cell apoptosis

• Published in: EMBO reports Vol. 3; no. 8; pp. 785 - 791
• Main Authors: Tanaka, Nobuyuki, Kamanaka, Masahito, Enslen, Hervé, Dong, Chen, Wysk, Mark, Davis, Roger J, Flavell, Richard A
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.08.2002; Oxford University Press
• Subjects: Alleles; Animals; Apoptosis; Blotting, Western; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; CD4-Positive T-Lymphocytes - metabolism; Cell Death; Cell Division; DNA - metabolism; Down-Regulation; Enzyme Activation; Immunoblotting; Interleukin-2 - metabolism; Ionomycin - pharmacology; Ionophores - pharmacology; MAP Kinase Kinase 3; MAP Kinase Kinase 6; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitogen-Activated Protein Kinase Kinases - metabolism; Mitogen-Activated Protein Kinases - metabolism; Models, Genetic; p38 Mitogen-Activated Protein Kinases; Precipitin Tests; Protein-Tyrosine Kinases - metabolism; Recombination, Genetic; Scientific Reports; T-Lymphocytes - pathology; Thymus Gland - cytology; Up-Regulation
• ISSN: 1469-221X; 1469-3178
• DOI: 10.1093/embo-reports/kvf153

The p38 mitogen‐activated protein kinase (p38MAPK) is activated in response to various stimuli, including cellular stress, inflammatory cytokines and cell surface receptors. The activation of p38MAPK is predominantly mediated by the two upstream MAPK kinases MKK3 and MKK6. To study the role of the p38MAPK pathway in vivo, we generated Mkk6−/− mice. We examined whether T‐cell apoptosis is affected in these mice and in our previously reported Mkk3−/− mice. Strikingly, in vivo deletion of double positive thymocytes in Mkk6−/− mice was impaired, whereas Mkk3−/− mice showed no apparent abnormality. Conversely, CD4+T cells from Mkk3−/− but not from Mkk6−/− mice were resistant to activation‐induced cell death and cytokine‐withdrawal‐induced apoptosis. In peripheral CD4+T cells, MKK3 is induced upon stimulation, whereas MKK6 is downregulated. These results suggest a novel mechanism regulating T‐cell apoptosis differentially through the p38MAPK pathway by MKK3 and MKK6.