GPX4 and gastric cancer: To explore the effect of CST1 on the ubiquitination of endogenous GPX4 in gastric cancer cells, we used the CST1 knockdown stable cell line MKN45-shNC/MKN45-sh1-CST1/MKN45-sh2-CST1, immunoprecipitated GPX4, respectively, and then detected the Ub level by WB.