Phage display identifies thioredoxin and superoxide dismutase as novel protein kinase C-interacting proteins: thioredoxin inhibits protein kinase C-mediated phosphorylation of histone

Using phage display we identify the redox proteins thioredoxin and superoxi de dismutase (SOD) as novel protein kinase C (PKC)-interacting proteins. Ov erlay assays demonstrated that PKC bound to immobilized thioredoxin, provid ing supporting evidence for the phage display results. Kinase assays demons trated that SOD and thioredoxin were not direct substrates for PKC but that both proteins blocked autophosphorylation of PKC, Moreover, thioredoxin in hibited PKC-mediated phosphorylation of histone (IC50 of approx. 20 ng/ml).