The surprising finding that an endolysosomal cation channel, TPC2 is involved in the regulation of GSK3β, and consequently β-Catenin and MITF levels in concert with Rab7a as an enhancer of the activity of TPC2 may add an additional layer of complexity, but may also contribute to a better understanding of the regulation of these central signaling components in cancer and melanoma and thus for novel therapeutic interventions46,47,53,56. Here, GSK3B is linked to melanoma.