Figure 4. TRIM55 interacts with and induces ubiquitination of DUSP1. (A, B) H9C2 cardiomyocytes were transduced with a TRIM55 expression vector or blank vector in the absence or presence of MG132 and then the expression of DUSP1 was measured. (C) H9C2 cardiomyocytes lysates were subjected to immunoprecipitation with control IgG, anti-DUSP1 or anti-TRIM55 antibody. The immunoprecipitates were then blotted with the indicated antibodies. (D) H9C2 cardiomyocytes transduced with a TRIM55 expression vector or blank vector were immunoprecipitated with anti-DUSP1, followed by immunoblotting with indicated antibodies. (E) H9C2 cardiomyocytes were co-transfected with a DUSP1 (WT) or mutant DUSP1 constructs along with the myc-TRIM55 and His-Ubiquitin constructs and then a pull-down assay was carried out. *P < 0.05, ***P < 0.001.