Fig. 4
DDX39B interacts with PKM2 and reduces its degradation. a The Gene Ontology analysis of DDX39B interactome. b The endogenous interaction between DDX39B and PKM2 was examined by immunoprecipitation assay in CRC cells. c GST pull-down assays were carried out with bacterially expressed GST-fused DDX39B and His-fused PKM2. d HCT116 and SW620 cells were transfected with pBiFC-VN173-DDX39B and/or pBiFC-VC155-PKM2, and the fluorescence signals were imaged. e The degradation of PKM2 protein in DDX39B knockdown CRC cells was measured by cycloheximide (CHX) chase analysis. f DDX39B-deficient CRC cells were treated with MG132 or chloroquine (CQ), and PKM2 protein levels were determined by western blotting. g The indicated CRC cells were transfected with plasmids expressing UbFlag and DDX39Bmyc, and cell lysates were immunoprecipitated with anti-PKM2 antibody followed by western blotting. h The binding affinity of PKM2 and STUB1 in CRC cells stably expressing mock or DDX39B was measured by immunoprecipitation assay. In vitro competitive binding analysis was executed with the indicated purified proteins, and the effect of DDX39B on PKM2WT-STUB1 (i) or PKM21–218,219aa-STUB1 (j) binding was determined by western blotting. Data represent as mean ± SD. The p values were determined by two-way ANOVA (e). ***p < 0.001
