Sharpin contributes to TNFα dependent NFκB activation and anti-apoptotic signalling in hepatocytes.
TNFα stimulates both pro- and anti-apoptotic signalling in hepatocytes. Anti-apoptotic signalling depends on a cascade of ubiquitylation steps leading to NFκB activation. Using Sharpin-deficient mice, we show that the ubiquitin binding protein Sharpin interacts with Hoip, an E3 ligase which generates linear ubiquitin chains. Sharpin-deficiency sensitized hepatocytes to induction of ... apoptosis by TNFα even in the absence of transcriptional inhibition. TNFα induced activation of NFκB was strongly reduced in hepatocytes from Sharpin-deficient mice, due to reduced and delayed phosphorylation and degradation of IκBα. Injection of TNFα-inducing lipopolysaccharides led to strongly exacerbated liver damage and premature death in Sharpin-deficient mice. Our findings point to an essential role of Sharpin in linear ubiquitin chain formation, NFκB activation, and protection of the liver against inflammatory damaging signals.
Mesh Terms:
Animals, Apoptosis, Gene Expression Profiling, Hepatocytes, Humans, Lipopolysaccharides, Liver Failure, Mice, Mice, Inbred C57BL, NF-kappa B, Nerve Tissue Proteins, Organ Specificity, Protein Binding, Rats, Signal Transduction, Tumor Necrosis Factor-alpha, Ubiquitin, Ubiquitin-Protein Ligases
Animals, Apoptosis, Gene Expression Profiling, Hepatocytes, Humans, Lipopolysaccharides, Liver Failure, Mice, Mice, Inbred C57BL, NF-kappa B, Nerve Tissue Proteins, Organ Specificity, Protein Binding, Rats, Signal Transduction, Tumor Necrosis Factor-alpha, Ubiquitin, Ubiquitin-Protein Ligases
PLoS ONE
Date: Jan. 19, 2012
PubMed ID: 22253853
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