Large-Scale Quantitative Proteomics Identifies the Ubiquitin Ligase Nedd4-1 as an Essential Regulator of Liver Regeneration

The liver is the only organ in mammals that fully regenerates even after major injury. To identify orchestrators of this regenerative response, we performed quantitative large-scale proteomics analysis of cytoplasmic and nuclear fractions from normal versus regenerating mouse liver. Proteins of the ubiquitin-proteasome pathway were rapidly upregulated after two-third hepatectomy, with the ubiquitin ligase Nedd4-1 being a top hit. In vivo knockdown of Nedd4-1 in hepatocytes through nanoparticle-mediated delivery of small interfering RNA caused severe liver damage and inhibition of cell proliferation after hepatectomy, resulting in liver failure. Mechanistically, we demonstrate that Nedd4-1 is required for efficient internalization of major growth factor receptors involved in liver regeneration and their downstream mitogenic signaling. 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. Finally, they identify an essential function of Nedd4-1 in tissue repair. •Proteomics identified regulated proteins and pathways in the regenerating liver•The ubiquitin ligase Nedd4-1 is an essential regulator of liver regeneration•Nedd4-1 promotes growth factor receptor internalization and efficient signaling•Posttranslational regulation of growth factor signaling controls liver regeneration Using large-scale quantitative proteomics, Bachofner, Speicher et al. identified the ubiquitin ligase Nedd4-1 as an essential regulator of liver regeneration. Nedd4-1 deficiency attenuated growth factor receptor internalization and signaling, demonstrating a crucial role of posttranslational modification of growth factor signaling in liver regeneration.