ATF4 and glioblastoma: In contrast, exogenous expression of ATF4 markedly upregulated the protein (Supplementary Fig. 2a) and mRNA (Supplementary Fig. 2b) expression of SLC2A5 and ALDOB, but not KHK and TKFC, suggesting that KHK and TKFC are expressed in GBM cells in an ATF4-independent manner.