Effect of PKC-zeta mediating Ang II-stimulated activation of CCDPK on rat cardiac fibroblast proliferation

AIM: To investigate whether the effect of angiotensin (Ang) II or epidermal growth factor (EGF) on cardiac fibroblast proliferation involved in activa tion of extracellular signal-regulated kinase (ERK) 1/2 or Ca2+-calmodulin dependent protein kinase(CCDPK) mediated by protein kinase C (PKC)-zeta. ME THODS: Relative activity of CCDPK was measured by Western blotting. DNA syn thesis was assayed by [H-3]thymidine incorporation. RESULTS: PDBU caused no decrease in Ang II- and 10 % FCS-stimulated CCDPK activity and DNA synthes is. In contrary, 65 % or 75 % EGF- or tetradecanoylphorbol acetate (TDPA, f ormally called PMA) stimulated CCDPK activity and 38 % or 42 % [H-3]thymidi ne incorporation treated by PDBU were inhibited, respectively. Meanwhile 70 % and 72 % CCDPK activities induced by Ang II and EGF were inhibited by PD 98059, respectively. CONCLUSION: PKC-zeta mediated Ang II-induced activati on of CCDPK and cardiac fibroblast proliferation.