Fig. 4: KHSRP interacts with SF3B1.

A The Flag-KHSRP protein was enriched with KHSRP antibody and detected using silver staining. Arrowhead represents the predicted size of KHSRP. B STRING network analysis of the KHSRP protein interactome. Red circles, mRNA splicing; blue circles, Nop56p-associated pre-rRNA complex; green circles, translation (left). KHSRP-interacting splicing complex enriched over IgG. Data from mass spectrometry analysis are shown in the table (right). Peptide-spectrum match counts (#PSM). U2 snRNPs are labeled in pink. C Coimmunoprecipitation of KHSRP and pre-mRNA splicing factors. Protein extracts from HL7702 cells were immunoprecipitated using the antibodies for KHSRP or SF3B1 and immunoblotted with the antibodies for the indicated proteins. HNRNPA1 was used as a positive control. D Schematic diagram of KHSRP truncations. The numbers shown indicate the amino acid position (top). Detection of the binding domain of KHSRP that interacts with SF3B1 in a coimmunoprecipitation assay using HL7702 cells that overexpressed different Flag-tagged KHSRP truncations (bottom). E Schematic diagram of SF3B1 truncations. The numbers shown indicate the amino acid position (top). Detection of the binding domain of SF3B1 that interacts with KHSRP in a coimmunoprecipitation assay using HL7702 cells that overexpressed different constructs with HA-tagged SF3B1 truncations (bottom). F The interaction between KHSRP-KH4Q and SF3B1-3 was tested in a cell-free system. The inputs and recombinant proteins that were pulled down were detected using Coomassie staining and Western blotting.