Characterization of protein dynamics after alpha-amanitin exposure in hepatoma cells

Alpha-amanitin (α-AMA) is a cyclic peptide and is one of the most lethal mushroom amatoxins found in Amanita phalloides. α-AMA is known to cause hepatotoxicity through RNA polymerase II inhibition, which acts in RNA and DNA translocation. To investigate the toxic signature of α-AMA beyond known mechanisms, we used quantitative nanoflow liquid chromatography-tandem mass spectrometry analysis coupled with tandem mass tag labeling to examine proteome dynamics in Huh-7 human hepatoma cells treated with toxic concentrations of α-AMA. We identified 1,828 proteins, quantified 1,563 proteins, and found a decrease of four subunits in T-complex protein 1-ring complex protein that was dependent on the α-AMA concentration. We conducted bioinformatics analyses of the quantified proteins to characterize the toxic signature of α-AMA in hepatoma cells. This is the first report of global proteome abundance changes according to α-AMA concentration variations and suggests a possible novel molecular regulation mechanism for hepatotoxicity.