The E3 ubiquitin ligase itch couples JNK activation to TNFα-induced cell death by inducing c-FLIPL turnover

Lufen Chang, Hideaki Kamata, Giovanni Solinas, Jun Li Luo, Shin Maeda, K. Venuprasad, Yun Cai Liu, Michael Karin

Research output: Contribution to journalArticlepeer-review

556 Scopus citations


The proinflammatory cytokine tumor necrosis factor (TNF) α signals both cell survival and death. The biological outcome of TNFα treatment is determined by the balance between NF-κB and Jun kinase (JNK) signaling; NF-κB promotes survival, whereas JNK enhances cell death. Critically, identity of a JNK substrate that promotes TNFα-induced apoptosis has been outstanding. Here we show that TNFα-mediated JNK activation accelerates turnover of the NF-κB-induced antiapoptotic protein c-FLIP, an inhibitor of caspase-8. This is not due to direct c-FLIP phosphorylation but depends on JNK-mediated phosphorylation and activation of the E3 ubiquitin ligase Itch, which specifically ubiquitinates c-FLIP and induces its proteasomal degradation. JNK1 or Itch deficiency or treatment with a JNK inhibitor renders mice resistant in three distinct models of TNFα-induced acute liver failure, and cells from these mice do not display inducible c-FLIPL ubiquitination and degradation. Thus, JNK antagonizes NF-κB during TNFα signaling by promoting the proteasomal elimination of c-FLIP L.

Original languageEnglish (US)
Pages (from-to)601-613
Number of pages13
Issue number3
StatePublished - Feb 10 2006
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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