To further test the importance of the ISR in PCa, we selectively depleted ATF4 using siRNA in LNCaP, MR49F, C4-2B, and PC-3 cells and observed similar growth inhibition for each cell line (Figure 1—figure supplement 1B, Figure 1—figure supplement 4, and Supplementary file 1). This evidence concerns the gene ATF4 and posterior cortical atrophy.