Mouse liver regeneration quantitative proteomics

The liver is the only organ in mammals, which fully regenerates after injury. To identify novel regulators of liver regeneration, we performed quantitative large-scale proteomics analysis of subcellular fractions from normal versus regenerating mouse liver. Proteins of the ubiquitin-proteasome pathway were rapidly regulated by partial hepatectomy, with the ubiquitin ligase Nedd4-1 being among the top hits. Knock-down of Nedd4-1 in hepatocytes in vivo through nanoparticle-mediated delivery of siRNA caused severe liver damage after partial hepatectomy and impaired regeneration, resulting in liver failure. Mechanistically, we demonstrate that Nedd4-1 is required for efficient activation of Erk1/2 signaling by receptor tyrosine kinases involved in liver regeneration through inhibition of receptor internalization, thus controlling a major pro-mitogenic and cytoprotective signaling pathway in the regenerating liver. These results highlight the power of large-scale proteomics to identify key players in liver regeneration and the importance of posttranslational regulation of growth factor signaling in this process.