Protein Phosphatase 4 Promotes Hepatocyte Lipoapoptosis by Regulating RAC1/MLK3/JNK Pathway

Figure 4

PP4 regulated JNK activation through a RAC1/MLK3 pathway in hepatocytes. Endoplasmic reticulum (ER) stress and RAC1/MLK3 signaling pathways were measured in palmitate-treated primary hepatocytes and HepG2 cells, PP4 inhibited and PP4 upregulated primary hepatocytes and HepG2 cells. Protein expressions of CHOP and phosphorylation levels of PERK and MLK3 were measured by western blot analysis. RAC1 activation was determined by binding to GST-PAK PBD and subsequent immunoblot analysis in palmitate-treated murine primary hepatocytes (a, c), HepG2 cells (e, g), AD-PP4shRNA and AD-PP4 pretreated murine primary hepatocytes (i, k), and PP4 siRNA-transfected HepG2 cells (m, o). Relative protein levels were quantified by densitometry and normalized (b, d, f, h, j, l, n, p). Data are expressed as , and statistical significance for protein levels was determined by Student’s -test or one-way ANOVA ().