BNIP3 and genetic control of necrosis-like cell death through the mitochondrial permeability transition pore.
Many apoptotic signaling pathways are directed to mitochondria, where they initiate the release of apoptogenic proteins and open the proposed mitochondrial permeability transition (PT) pore that ultimately results in the activation of the caspase proteases responsible for cell disassembly. BNIP3 (formerly NIP3) is a member of the Bcl-2 family that is expressed in mitochondria and induces apoptosis without a functional BH3 domain. We report that endogenous BNIP3 is loosely associated with mitochondrial membrane in normal tissue but fully integrates into the mitochondrial outer membrane with the N terminus in the cytoplasm and the C terminus in the membrane during induction of cell death. Surprisingly, BNIP3-mediated cell death is independent of Apaf-1, caspase activation, cytochrome c release, and nuclear translocation of apoptosis-inducing factor. However, cells transfected with BNIP3 exhibit early plasma membrane permeability, mitochondrial damage, extensive cytoplasmic vacuolation, and mitochondrial autophagy, yielding a morphotype that is typical of necrosis. These changes were accompanied by rapid and profound mitochondrial dysfunction characterized by opening of the mitochondrial PT pore, proton electrochemical gradient (Deltapsim) suppression, and increased reactive oxygen species production. The PT pore inhibitors cyclosporin A and bongkrekic acid blocked mitochondrial dysregulation and cell death. We propose that BNIP3 is a gene that mediates a necrosis-like cell death through PT pore opening and mitochondrial dysfunction.
Vande Velde
C
C
The Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Manitoba R3E 0V9.
Cizeau
J
J
Dubik
D
D
Alimonti
J
J
Brown
T
T
Israels
S
S
Hakem
R
R
Greenberg
A H
AH
D051033:Apoptosis Inducing Factor; D053477:Apoptotic Protease-Activating Factor 1; D001865:Bongkrekic Acid / Q000494:pharmacology; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000235:genetics*; D002460:Cell Line; D016572:Cyclosporine / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D005347:Fibroblasts / Q000473:pathology / Q000648:ultrastructure; D005420:Flavoproteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D008565:Membrane Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009336:Necrosis; D010539:Permeability; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species / Q000378:metabolism; D025521:Tumor Suppressor Proteins
C494829:AIFM1 protein, human; C506592:APAF1 protein, human; D051033:Apoptosis Inducing Factor; D053477:Apoptotic Protease-Activating Factor 1; C090121:BNIP3 protein, human; C116838:BNIP3L protein, human; D003574:Cytochrome c Group; D005420:Flavoproteins; D008565:Membrane Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; D025521:Tumor Suppressor Proteins; D001865:Bongkrekic Acid; D016572:Cyclosporine; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases