title: The proapoptotic protein BNIP3 interacts with VDAC to induce mitochondrial release of endonuclease G.
abstract: BNIP3 is a proapoptotic protein that induces cell death through a mitochondria-mediated pathway. We reported previously that mitochondrial localization of BNIP3 and translocation of EndoG from mitochondria to the nucleus are critical steps of the BNIP3 pathway. It is not clear, however, that how BNIP3 interacts with mitochondria. Here we show that expression of BNIP3 resulted in mitochondrial release and nuclear translocation of EndoG. Incubation of a recombinant GST-BNIP3 protein with freshly isolated mitochondria led to the integration of BNIP3 into mitochondria, reduction in the levels of EndoG in mitochondria and the presence of EndoG in the supernatant that was able to cleave chromatin DNA. Co-immunoprecipitation and mass spectrometry analysis reveals that BNIP3 interacted with the voltage-dependent anion channel (VDAC) to increase opening probabilities of mitochondrial permeability transition (PT) pores and induce mitochondrial release of EndoG. Blocking VDAC with a VDAC antibody largely abolished mitochondrial localization of BNIP3 and prevented EndoG release. Together, the data identify VDAC as an interacting partner of BNIP3 and support endonuclease G as a mediator of the BNIP3 pathway.
authors.affiliation: Institute of Pathology and Southwest Cancer Center, The Third Military Medical University, Chongqing, China; Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Xiaosha
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Pathology and Southwest Cancer Center, The Third Military Medical University, Chongqing, China.
authors.forename: Xiuwu
authors.initials: X
authors.lastname: Bian
authors.affiliation: Institute of Pathology and Southwest Cancer Center, The Third Military Medical University, Chongqing, China; Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Jiming
authors.initials: J
authors.lastname: Kong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D050994:Voltage-Dependent Anion Channels / Q000378:metabolism*
chemical_list: C090121:BNIP3 protein, human; C505650:BNIP3 protein, rat; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins; D011518:Proto-Oncogene Proteins; D050994:Voltage-Dependent Anion Channels; D004706:Endodeoxyribonucleases; C052391:endonuclease G