Fig. 7: PDL1 signaling activates Sox10-regulated Mitf-Gpnmb axis.

a Sox10- or Mitf-targeted or control shRNA was transfected into P4 cells and determined by qRT-PCR for expression of indicated genes. Mitf gene expression is shown as transcripts of Mitf common regions. Expression is shown as % of control gene expression in control shRNA-transfected cells (mean ± SEM, n = 3). b RenCa or Caki-2 cells were cultured for 0 (immediately harvested), 1, and 2 days with immobilized anti-PDL1 Ab and quantified for SOX10 gene expression (mean ± SEM, n = 3). c Deletion mutant analysis of PDL1 signaling. The cytoplasmic amino acid sequences of all mutants with deletion or amino acid substitution are schematically presented. The entire cytoplasmic region is shown at the top. The deleted region is shown by gray-filled bars, with amino acid residues of the junction between both ends. Lysine-to-arginine substitution at 171 aa (R171) or 280 aa (R280) is also constructed. These genes were separately transfected into 293T cells and assayed for upregulated SOX10 gene expression by PDL1-crosslinking and expressed as % of WT-induced full rise (mean ± SEM, n = 3). Data are representative of at least two experiments. p values are shown, compared to control using Student’s t-test.