ERBB3 and melanoma: To address whether depletion of MITF protein activates the PI3K pathway through NRG1-beta/ERBB3 signaling in both mutant and wild-type BRAF melanoma cell lines, we co-transfected WM983B and MeWo with MITF and ERBB3 siRNA molecules in combination with NRG1-beta treatment (Figure 3A–3B), or without NRG1-beta treatment (See Supplementary Figure S3A-S3B).