Fig. 4

KCTD9 affects the level of ubiquitination of TOP2A. a Interactions between TOP2A and TOP2B and KCTD9 in the String database. Protein expression of TOP2A (b) and TOP2B (c) in LUAD was analyzed in the UALCAN database. d Multiple ubiquitination modification sites are present in TOP2A in the GPS-Uber database. e The mRNA expression of KCTD9 in LUAD cells after infection of sh-NC or sh-KCTD9 was verified using RT-qPCR. f The mRNA expression of TOP2A in LUAD cells after infection of sh-NC or sh-KCTD9 was verified using RT-qPCR assays. g The protein expression of TOP2A in LUAD cells after infection of sh-NC or sh-KCTD9 was verified using western blot assays. The expression of TOP2A in A549 (h) and HCC827 (i) cells after infection of sh-NC or sh-KCTD9 in the presence of CHX. j Effect of KCTD9 on TOP2A ubiquitination detected by immunoprecipitation. k The protein expression of TOP2A in LUAD cells after infection of sh-NC or sh-KCTD9 with the proteasome inhibitor MG132 treatment. Data are presented as the mean ± SD of results from at least three independent experiments performed in triplicates, two-way ANOVA with Tukey’s posttest, *p < 0.05