title: Characterization of a novel and specific inhibitor for the pro-apoptotic protease Omi/HtrA2.
abstract: Omi/HtrA2 is a mammalian serine protease with high homology to bacterial HtrA chaperones. Omi/HtrA2 is localized in mitochondria and is released to the cytoplasm in response to apoptotic stimuli. Omi/HtrA2 induces cell death in a caspase-dependent manner by interacting with the inhibitor of apoptosis protein as well as in a caspase-independent manner that relies on its protease activity. We describe the identification and characterization of a novel compound as a specific inhibitor of the proteolytic activity of Omi/HtrA2. This compound (ucf-101) was isolated in a high throughput screening of a combinatorial library using bacterially made Omi-(134-458) protease and fluorescein-casein as a generic substrate. ucf-101 showed specific activity against Omi/HtrA2 and very little activity against various other serine proteases. This compound has a natural fluorescence that was used to monitor its ability to enter mammalian cells. ucf-101, when tested in caspase-9 (-/-) null fibroblasts, was found to inhibit Omi/HtrA2-induced cell death.
authors.affiliation: Biomolecular Science Center and Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, Florida 32826, USA.
authors.forename: Lucia
authors.initials: L
authors.lastname: Cilenti
authors.forename: Younghee
authors.initials: Y
authors.lastname: Lee
authors.forename: Sibylle
authors.initials: S
authors.lastname: Hess
authors.forename: Srinivasa
authors.initials: S
authors.lastname: Srinivasula
authors.forename: Kwon Moo
authors.initials: KM
authors.lastname: Park
authors.forename: Daniela
authors.initials: D
authors.lastname: Junqueira
authors.forename: Hedvika
authors.initials: H
authors.lastname: Davis
authors.forename: Joseph V
authors.initials: JV
authors.lastname: Bonventre
authors.forename: Emad S
authors.initials: ES
authors.lastname: Alnemri
authors.forename: Antonis S
authors.initials: AS
authors.lastname: Zervos
mesh_terms: D017209:Apoptosis; D004591:Electrophoresis, Polyacrylamide Gel; D016650:Fluorescein-5-isothiocyanate; D000074923:High-Temperature Requirement A Serine Peptidase 2; D006868:Hydrolysis; D024101:Mitochondrial Proteins; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D012697:Serine Endopeptidases / Q000187:drug effects* / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*
chemical_list: D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases; D000074923:High-Temperature Requirement A Serine Peptidase 2; D016650:Fluorescein-5-isothiocyanate