In U87MG cells and other GBM cell lines, RIOK1 or RIOK2 knockdown induced up-regulation of p53 and the p21 cdk inhibitor, a p53 transcriptional target (Figure 5F, Figure S13, S14), and coincident knockdown of RpL11 and RIOK1 or RIOK2 blocked induction of p53 and p21 (Figure 5F and Figure S14). Here, RIOK1 is linked to glioblastoma.