Title: Signal transduction by stress‐activated MAP kinases
Abstract: The JNK group of stress‐activated MAP kinases consists of ten protein kinases that phosphorylate the NH2‐terminal activation domain of c‐Jun on Ser‐63 and Ser‐73 causing increased transcriptional activity. JNK protein kinase activity is increased in response to treatment of cells with pro‐inflammatory cytokines or exposure to environmental stress. Activated JNK is phosphorylated on Thr and Tyr within the tripeptide motif Thr‐Pro‐Tyr located in kinase sub‐domain VIII. Mutational analysis demonstrates that JNK activation requires the phosphorylation of both Thr and Tyr within this motif. This phosphorylation is mediated by dual specificity protein kinases, including MKK4 and MKK7. The function of the JNK signaling pathway has been studied using a combination of biochemical and genetic approaches. Genetic analysis of JNK signaling in Drosophila demonstrates that JNK is required for early embryonic morphogenesis. Similarly, disruption of the JNK signaling pathway in mice using homologous recombination demonstrates that JNK is required for embryonic viability. In contrast, mice with genetically engineered selective defects in JNK signaling are viable, but exhibit changes in stress‐induced gene expression and apoptosis. These studies provide insight into the role of the JNK stress‐activated MAP kinase pathway in the cellular response to environmental stress, including apoptosis and cell survival.
Publication Year: 2008
Publication Date: 2008-03-01
Language: en
Type: article
Indexed In: ['crossref']
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