Proteolytic activation of PKN by caspase-3 or related protease during apoptosis.
PKN, a fatty acid- and Rho-activated serine/threonine kinase having a catalytic domain highly homologous to protein kinase C (PKC), was cleaved at specific sites in apoptotic Jurkat and U937 cells on Fas ligation and treatment with staurosporin or etoposide, respectively. The cleavage of PKN occurred with a time course similar to that of PKCdelta, a known caspase substrate. This proteolysis was inhibited by a caspase inhibitor, acetyl-Asp-Glu-Val-Asp-aldehyde. The cleavage fragments were generated in vitro from PKN by treatment with recombinant caspase-3. Site-directed mutagenesis of specific aspartate residues prevented the appearance of these fragments. These results indicate that PKN is cleaved by caspase-3 or related protease during apoptosis. The major proteolysis took place between the amino-terminal regulatory domain and the carboxyl-terminal catalytic domain, and it generated a constitutively active kinase fragment. The cleavage of PKN may contribute to signal transduction, eventually leading to apoptosis.
Takahashi
M
M
Department of Biology, Faculty of Science, Kobe University, Kobe 657-8501, Japan.
Mukai
H
H
Toshimori
M
M
Miyamoto
M
M
Ono
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001665:Binding Sites / Q000235:genetics; D019556:COS Cells; D053148:Caspase 3; D020169:Caspases; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
D015853:Cysteine Proteinase Inhibitors; D009842:Oligopeptides; D010446:Peptide Fragments; D011994:Recombinant Proteins; C108637:aspartyl-glutamyl-valyl-aspartal; C061570:protein kinase N; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D010450:Endopeptidases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases