Figure 4.

The TM domain is indispensable for TMEPAI to mediate c-Maf ubiquitination and biological activity. A, the schematic drawing of the TMEPAI truncated constructs. B, c-Maf was co-transfected with full-length or truncated TMEPAI constructs, respectively, into HEK293T cells for 24 h, followed by immunoblotting assay. C, c-Maf was co-transfected with wildtype TMEPAI or TM-deleted TMEPAI into HEK293T cells. 16 h later, the cells were subjected to protein extraction, immunoprecipitation/immunoblotting assays. D, the MARE-driving firefly luciferase and c-Maf plasmids were co-transfected into HEK293T cells along with full-length or TM-deleted TMEPAI constructs for 24 h, followed by luciferase assay and immunoblotting assay. **, p < 0.001. E and F, the c-Maf plasmid was co-transfected into HEK293T cells with the TMEPAI construct containing a part of the TM domain (sTMEPAI) for 24 h at indicated concentration (E) or 1 μg for indicated periods (F), followed by immunoblotting assay. TCL, total cell lysates.