title: Proteolytic activation of protein kinase C delta and epsilon by caspase-3 in U937 cells during chemotherapeutic agent-induced apoptosis.
abstract: Protein kinase C (PKC) family members play pivotal roles in cellular signal transduction and nPKCdelta and theta are known to be subjected to restrictive proteolysis during apoptosis. Here we show that nPKCepsilon was specifically cleaved and generates 43-kDa and 36-kDa C-terminal fragments during chemotherapeutic drug-induced apoptosis. The proteolytic cleavage of nPKCdelta and epsilon was completely inhibited by pretreatment with Ac-DEVD-cho, a specific inhibitor of caspase-3 family enzymes. Furthermore, nPKCepsilon in non-treated U937 cell lysates was cleaved by purified recombinant caspase-3 to generate the 43-kDa fragment, identical in size to the fragment observed in vivo. This cleavage was prevented by the addition of Ac-DEVD-cho. These results suggest that caspase-3 specifically cleaves nPKCepsilon. These findings suggest the possibility that nPKC subfamily members are generally involved in the execution of apoptosis but they are regulated diversely depending on the different apoptotic stimuli.
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku.
authors.forename: H
authors.initials: H
authors.lastname: Koriyama
authors.forename: Z
authors.initials: Z
authors.lastname: Kouchi
authors.forename: T
authors.initials: T
authors.lastname: Umeda
authors.forename: T C
authors.initials: TC
authors.lastname: Saido
authors.forename: T
authors.initials: T
authors.lastname: Momoi
authors.forename: S
authors.initials: S
authors.lastname: Ishiura
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D002166:Camptothecin / Q000494:pharmacology; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003561:Cytarabine / Q000494:pharmacology; D004789:Enzyme Activation; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism / Q000494:pharmacology; D020298:U937 Cells; D019014:fas Receptor / Q000276:immunology
chemical_list: D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D007527:Isoenzymes; D009842:Oligopeptides; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; D019014:fas Receptor; D003561:Cytarabine; D005047:Etoposide; C497258:PRKCD protein, human; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate; D002166:Camptothecin