Figure 1.

Interaction between ubiquitin specific peptidase 4 (USP4) and interferon regulatory factor 4 (IRF4). (A) IRF4 was co-immunoprecipitated by the anti-Ha antibody when Ha-USP4 and Myc-IRF4 were coexpressed. (B) IRF4 was co-immunoprecipitated by the anti-Ha antibody when Ha-USP4 and Myc-IRF4 were coexpressed, and USP4 was co-immunoprecipitated by the anti-Myc antibody when Ha-USP4 and Myc-IRF4 were coexpressed. (C) IRF4 was co-immunoprecipitated by the anti-USP4 antibody, indicating that USP4 interacts with IRF4 in Th2 cells. Flag-IRF4 and Ha-USP4 were co-transfected into 293T cells. After 48 h, the cells were retrieved, and 1 µg of anti-Ha or anti-Flag monoclonal antibody precipitate was added and immunoblotting was conducted in A and B. Th2 cells were amplified to 1×10⁷, and co-immunoprecipitated with 1 µg of normal IgG or anti-USP4, then immunoblotting assay was conducted in C.