The J domain of pDNAJB6 is essential for its interaction with Cap. A, B Schematic representation of mutants of Cap and pDNAJB6. C, D GST pull-down assay. GST or GST fusion proteins were incubated with the indicated proteins and the bound proteins were analyzed by SDS-PAGE. GFP-tagged proteins and GST-tagged proteins were detected by Western blot. E, F The J domain of pDNAJB6 and the fragment (162-234 aa) of Cap are required for the interaction of pDNAJB6 with Cap. HEK-293T cells were transfected with the indicated plasmids, and cell lysates were immunoprecipitated with anti-Flag or anti-GFP antibodies followed by immunoblots using anti-GFP or anti-Flag antibodies.