title: Complestatin prevents apoptotic cell death: inhibition of a mitochondrial caspase pathway through AKT/PKB activation.
abstract: Complestatin, a bicyclo hexapeptide from Streptomyces, was isolated as a possible regulator of neuronal cell death. In this study, we report an anti-apoptotic activity of complestatin and its underlying molecular mechanism. Complestatin blocked TRAIL (TNF-related apoptosis-inducing ligand)-induced apoptosis and activation of caspase-3 and -8 at micromolar concentration levels without inhibiting the catalytic activities of these caspases. Complestatin potently induced a rapid and sustained AKT/PKB activation and Bad phosphorylation, resulting in inhibition of mitochondrial cytochrome c release. These anti-apoptotic activities of complestatin were significantly abrogated in cells expressing dominant negative AKT/PKB. Taken together, our results suggest that complestatin prevents apoptotic cell death via AKT/PKB-dependent inhibition of the mitochondrial apoptosis signal pathway. The novel property of complestatin may be valuable for developing new pharmaceutical means that will control unwanted cell death.
authors.affiliation: Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chunchon, Kangwon-Do 200-701, Republic of Korea.
authors.forename: Eok-Cheon
authors.initials: EC
authors.lastname: Kim
authors.forename: Bong-Sik
authors.initials: BS
authors.lastname: Yun
authors.forename: In-Ja
authors.initials: IJ
authors.lastname: Ryoo
authors.forename: Jeong-Ki
authors.initials: JK
authors.lastname: Min
authors.forename: Moo-Ho
authors.initials: MH
authors.lastname: Won
authors.forename: Kwang-Soon
authors.initials: KS
authors.lastname: Lee
authors.forename: Young-Myeong
authors.initials: YM
authors.lastname: Kim
authors.forename: Ick -Dong
authors.initials: I-
authors.lastname: Yoo
authors.forename: Young-Guen
authors.initials: YG
authors.lastname: Kwon
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000037:antagonists & inhibitors; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002733:Chlorophenols / Q000494:pharmacology*; D045304:Cytochromes c / Q000037:antagonists & inhibitors; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D010456:Peptides, Cyclic / Q000494:pharmacology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002352:Carrier Proteins; D061945:Caspase Inhibitors; D002733:Chlorophenols; D008562:Membrane Glycoproteins; D010456:Peptides, Cyclic; D011518:Proto-Oncogene Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; C023490:complestatin; D045304:Cytochromes c; D011505:Protein-Tyrosine Kinases; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020169:Caspases