Because ATF4 knockdown reduces neuronal RhoGDIα, and because RhoGDIα knockdown diminishes Rho family GTPase protein levels in different cell types, including Hela, fibroblast, breast epithelial, melanoma, and endothelial cells30, we asked whether RhoGDIα depletion would mimic the effect of ATF4 knockdown on Rho family protein levels in neurons. The gene discussed is ATF4; the disease is melanoma.