title: The mitochondrial serine protease HtrA2/Omi cleaves RIP1 during apoptosis of Ba/F3 cells induced by growth factor withdrawal.
abstract: Interleukin-3 (IL-3) deprivation of the mouse pro-B cell line Ba/F3 induces cell death that is abrogated by B-cell lymphoma 2 (Bcl-2) overexpression, but remains unaffected by the pan-caspase inhibitor carbobenzoxy-valyl-analyl-aspartyl-[O-methyl]-fluoromethylketone (zVAD-fmk). IL-3 withdrawal causes receptor-interacting protein (RIP)1 cleavage into C-terminal fragments of 30 and 25 kDa, and only cleavage leading to the former was prevented by zVAD-fmk. siRNA experiments demonstrated that generation of the 25-kDa fragment was due to a Bcl-2-modulated release of the mitochondrial serine protease high temperature requirement protein A2 (HtrA2)/Omi. Accordingly, recombinant HtrA2/Omi efficiently cleaved mouse RIP1 in vitro, generating fragments matching those observed in IL-3-deprived Ba/F3 cells. The HtrA2/Omi cleavage site in mouse RIP1 was mapped to the intermediate domain and the corresponding N- and C-terminal fragments were impaired in their ability to activate nuclear factor-kappaB, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase. Interestingly, knockdown of HtrA2/Omi afforded protection against IL-3 withdrawal-induced death in the presence of zVAD-fmk, demonstrating a role for HtrA2/Omi in caspase-independent cell death during growth factor withdrawal by cleaving RIP1.
authors.affiliation: VIB, Department for Molecular Biomedical Research, B-9052 Zwijnaarde, Belgium.
authors.forename: Lieselotte
authors.initials: L
authors.lastname: Vande Walle
authors.forename: Ellen
authors.initials: E
authors.lastname: Wirawan
authors.forename: Mohamed
authors.initials: M
authors.lastname: Lamkanfi
authors.forename: Nele
authors.initials: N
authors.lastname: Festjens
authors.forename: Jelle
authors.initials: J
authors.lastname: Verspurten
authors.forename: Xavier
authors.initials: X
authors.lastname: Saelens
authors.forename: Tom
authors.initials: T
authors.lastname: Vanden Berghe
authors.forename: Peter
authors.initials: P
authors.lastname: Vandenabeele
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D000074923:High-Temperature Requirement A Serine Peptidase 2; D007377:Interleukin-3 / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000201:enzymology*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D054448:Precursor Cells, B-Lymphoid / Q000276:immunology / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D007377:Interleukin-3; D024101:Mitochondrial Proteins; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D012697:Serine Endopeptidases; D000074923:High-Temperature Requirement A Serine Peptidase 2; C000615915:Htra2 protein, mouse; D020169:Caspases