Fig. 5. Inhibition of PKC activity prevents glutamate-induced downregulation of MKP-1. HT22 cells were transfected with either a mock vector or a dominant-negative mutant (DN) of PKC (PKC DN) vector. After 12 hours, cells were exposed to 5 mM glutamate (Glu) for 7 hours. Western blot analysis was performed using specific antibodies against MKP-1 and actin. The relative MKP-1 protein levels were calculated by averaging the results obtained from three independent experiments. ^*P<0.05, ns, not significant.