(A) Hepcidin promoter responses by BMP2 and HJV, in the presence of matriptase-2 (MT2). A firefly luciferase reporter driven by 2.9 kb of the proximal hepcidin promoter was cotransfected into Hep3B cells with pRL-TK, either alone or with HJV and/or MT2 expressing vectors. Relative luciferase activity is calculated as reported in material and method and expressed as a multiple of the activity of cells transfected with the reporter alone. (B) Dose dependent modulation of the hepcidin activity by MT2. Hep3B cells were transfected with increasing concentrations of wild type or mutant MT2 expressing vectors in the presence of fixed amount of HJV expressing vector and treated or not with BMP2 (50 ng/ml). The fold induction is calculated as a ratio between the MT2-mediated and the mock-mediated hepcidin promoter activity, calculated as described in (A). Experiments, made in triplicate, were performed three times. Error bars indicate SD. Exact P-values are shown above bars.