| First Author | Wang Z | Year | 2008 |
| Journal | J Biol Chem | Volume | 283 |
| Issue | 30 | Pages | 21011-23 |
| PubMed ID | 18508759 | Mgi Jnum | J:137929 |
| Mgi Id | MGI:3803411 | Doi | 10.1074/jbc.M802229200 |
| Citation | Wang Z, et al. (2008) Mitogen-activated protein kinase phosphatase-1 represses c-Jun NH2-terminal kinase-mediated apoptosis via NF-kappaB regulation. J Biol Chem 283(30):21011-23 |
| abstractText | The mechanism regulating radiation-induced anti-apoptotic response, a limiting factor in improving cell radiosensitivity, remains elusive. Mitogen-activated protein kinase (MAPK) phosphatase (MKP)-1 is the major member of MKPs that dephosphorylates and inactivates MAPK. Here we provide the evidence that MKP-1 was negatively bridging between NF-kappaB-mediated prosurvival pathway and c-Jun N-terminal kinase (JNK)-mediated proapoptotic response. MKP-1 was induced by gamma-radiation and repressed radiation-induced pro-apoptotic status. NF-kappaB RelA/p50 heterodimer was recruited to MKP-1 gene promoter to induce MKP-1 transcription. Deletion of the NF-kappaB-binding site or inactivation of NF-kappaB by its small interfering RNA significantly decreased the radiation-induced MKP-1 promoter activity. In addition, MKP-1-deficient mouse embryonic fibroblasts exhibited a prolonged activation of JNK but not p38 or extracellular signal-regulated kinase subfamilies of MAPKs. The prolonged activation of JNK was not induced by treatment with tumor necrosis factor alpha or interleukin-6, and inactivation of JNK but not p38 or ERK abolished radiation-induced proapoptotic status, indicating that JNK is specifically inhibited by radiation-induced MKP-1. Three MKP-1 wild type human tumor cell lines treated with MKP-1 small interfering RNA showed an increased proapoptotic response that can be rescued by overexpression of wild type mouse MKP-1. Together, these results suggest that MKP-1 is a NF-kappaB-mediated prosurvival effector in attenuating JNK-mediated pro-apoptotic response; NF-kappaB/MKP-1-mediated negative JNK regulation represents a potential therapeutic target for adjusting cell radiosensitivity. |
