Phorbol 12-myristate 13-acetate (PMA), a potent activator of protein kinase C (PKC), induces PKR degradation [41] . Because the general PKC inhibitor, GÖ 6983, suppresses PMA-mediated PKR degradation [41] , we examined whether the NSs promoted PKR downregulation through PKC by treating MP-12-infected cells with GÖ 6983. Treatment of GÖ 6983 did not inhibit the NSs-mediated PKR downregulation ( Figure 7F, lane 8) , suggesting that PKC was not involved in NSs-induced PKR downregulation.