An expression vector containing three copies of the AP-1 binding element (TRE) upstream of a thymidine kinase promotor which controlled the expression of the chloramphenicol acetyl transferase (CAT) gene was transiently transfected into vascular smooth muscle (VSM) cells and a human hepatocarcinoma cell line, Hep G2. Twelve hours of angiotensin (Ang) II exposure stimulated significantly CAT expression by 3.4 fold and 2.7 fold in Hep G2 and VSM cells, respectively. AngII had no effect on CAT expression of a control vector. This AngII-induced stimulation was attenuated significantly by an AngII receptor antagonist, Sar1 Ile8 AngII, and abolished completely by a PKC inhibitor, staurosporine. Our data suggest that the TRE plays a crucial role in AngII-induced gene expression that is mediated by PKC. We concluded that TRE is one of the AngII-responsive elements.