Phosphorylation of eIF2α was induced by thapsigargin (1.5 μM for SH-SY5Y cells, 7.5 μM for melanoma cells) within 15 min of treatment with fenretinide in SH-SY5Y cells and within 4 h of treatment in A375 cells (Figure 2C). Here, EIF2A is linked to melanoma.