Fig. 5

CircSCAP directly interacts with SF3A3 protein. A CircSCAP binding proteins were pulled down via circSCAP probe in A549 cells and displayed by silver staining. B All precipitated complex pulled down by circSCAP and negative control probe were subjected to mass spectrum analysis. A total of 633 proteins were enriched for circSCAP probe when compared with negative control, among which 4 of top 10 proteins were involved in splicesome. C-D Top 4 candidate proteins of splicesome pulled down by circSCAP probe were validated via immunoblotting (D). CircSCAP directly interacted with SF3A3 protein, as shown by mass spectrum (C) and immunoblotting (D) in A549 cells. E–F RNA Immunoprecipitation (RIP) assay was performed to confirm the interaction of circSCAP and SF3A3 protein in A549 (E) and H1650 cells (F). G CircSCAP overexpression significantly decreased while knock-down enhanced SF3A3 protein level in NSCLC cell lines. H CircSCAP level showed no effects on the mRNA level of SF3A3. Data represent the mean ± SD of triplicate experiments and were analyzed by Student t test. * means P < 0.05