Comprehensive proteomic and transcriptomic characterization of hepatic expression signatures affected in p14 liver conditional knockout mice

Scaffold proteins regulate intracellular MAP kinase signaling by providing critical spatial and temporal specificity. We have shown previously that the scaffold protein MEK1 partner (MP1) is localized to late endosomes by the adaptor protein p14. Using conditional gene disruption of p14 in livers of mice we analysed protein and transcript signatures in tissue samples. Further biological network analysis predicted that the differentially expressed transcripts and proteins are involved in cell cycle progression and regulation of cellular proliferation. Although some of the here identified signatures were previously linked to phospho-ERK activity, most of them were novel targets of late endosomal p14/MP1/MEK/ERK signaling module. Finally, the proliferation defect was confirmed in a chemically induced liver regeneration model in p14 liver knock-out mice. Conditional liver p14 KO mice were generated by mating p14 f/f mice with mice expressing Cre recombinase under control of Alb promoter and alpha-fetoprotein enhancer. The obtained p14 floxed/floxed;AlfpCre(p14 liver KO) mice were used in experiments as KO mice. To prevent the influence of AlfpCre transgene we used p14 +/+;AlfpCre mice as a control. All mice were derived in a C57BL/6 background and were six weeks old. Expression profiles of KO mouse samples were compared to expression profiles of corresponding control mice and differentially expressed genes were identified.