Genome-wide profiling of TFEB targets in melanoma

Unlike MITF-M, the melanocyte-specific isoform of MITF, TFEB, TFE3 and non-melanocyte MITF isoforms are regulated primarily by mTORC1-mediated phosphorylation at the lysosome that promotes their cytoplasmic retention. As low levels of glucose or amino acids trigger down-regulation of MITF, it is likely that on nutrient limitation some MITF functions are assumed by TFE3 and TFEB, enabling MITFLow melanoma cells to survive and proliferate. The role TFEB and TFE3 in melanoma biology and their impact on MITF-driven proliferation is poorly understood. Overall design: 501mel melanoma cell lines engineered to express ectopic-doxycycline-inducible-HA-epitope-tag TFEB. Cells were then treated with 5ng Dox overnight to attain expression of ectopic TFEB that was comparable to the endogeneous level. The following day cells were treated with 250nM Torin1 or control for 6h. Samples were then processed as described below.