A The proteins interacting with CDK13 in PC3 cells identified by co-immunoprecipitation coupled with mass spectrometry (CoIP-MS). B The indicated seven genes were knocked down in PC3 and C4-2 cells by their corresponding siRNAs, and the RT-qPCR detected the ACC1 mRNA expression. C CoIP coupled with Western blot was performed to verify the interaction between CDK13 and NSUN5. D Proximity ligation assay (PLA) detected CDK13 and NSUN5 interaction by using the indicated antibodies. E PC3 cells were transfected with shCDK13 or control vector, and then double immunofluorescence staining was used to detect CDK13 and NSUN5 co-localization. F, G PC3 and C4-2 cells were transfected with oeNSUN5 or shCDK13 or both together, and then Western blot and RT-qPCR detected ACC1 and ACLY expression. H TG and cholesterol contents were measured as quantitative indicators of lipid accumulation in PC3 and C4-2 cells. K PC3 and C4-2 cells were transfected as in (F), and MTS assay detected cell viability. I, J Cells were transfected as in (F), and clone formation assay detected cell growth. All data are expressed as the mean ± SEM of 3 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001 vs. their corresponding controls.