MAPK11 and gastric cancer: To investigate the cellular function performed by p38α-SUMOylation in GC, we established p38α, but not p38β, knock-out cell lines MGC803/p38αKO and HGC27/p38αKO with the CRISPR-Cas9 system, and the resultant colonies were validated by Western blotting and genotyping (Fig. S2b–d).