RPS6KA3 and melanoma: To investigate a potential general role of RSK in melanoma with hyperactivated MAPK signaling, we used a panel of cell lines including melanoma cells with activating NRAS mutations (NRASMut), BRAF mutations (BRAFMut) or an NF-1 loss-of-function (NF-1LOF) (Fig. 1A; Suppl.