Ikappa b-alpha, the NF-kappa B inhibitory subunit, interacts with ANT, the mitochondrial ATP/ADP translocator.
The transcription factor NF-kappaB regulates a wide set of genes involved in the establishment of many cellular processes that control cell activation, proliferation, and apoptosis. IkappaB inhibitory subunits integrate NF-kappaB activation signals through phosphorylation and ubiquitination of its N-terminal domain. Using the two-hybrid system in yeast, we searched for IkappaB-alpha N-terminal domain interactors and therefore potential NF-kappaB regulators. An interaction of IkappaB-alpha with the mitochondrial ATP/ADP translocator ANT was detected in yeast and confirmed in glutathione S-transferase pull-down assays and co-precipitation experiments in transfected cells. Subcellular cell fractionation, resistance to proteinase K treatment, and electron microscopy experiments demonstrated the presence of IkappaB-alpha and associated p65 NF-kappaB in the mitochondrial intermembrane space. IkappaB-alpha.NF-kappaB appeared to be released from mitochondria upon the induction of apoptosis by engagement of the Fas receptor. These data suggest that the mitochondrial IkappaB-alpha.NF-kappaB pool participates in the regulation of apoptosis.
Bottero
V
V
INSERM U526 "Activation des Cellules Hématopoiétiques," IFR50, Faculté de Médecine Pasteur, 06107 Nice cedex 2, France.
Rossi
F
F
Samson
M
M
Mari
M
M
Hofman
P
P
Peyron
J F
JF
D017209:Apoptosis; D002460:Cell Line; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism*; D017930:Genes, Reporter; D005982:Glutathione Transferase / Q000235:genetics; D015368:Human T-lymphotropic virus 1 / Q000235:genetics; D006801:Humans; D020672:I-kappa B Proteins; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D019169:Jurkat Cells; D007700:Kinetics; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D000226:Mitochondrial ADP, ATP Translocases / Q000737:chemistry / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D021122:Protein Subunits; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D021122:Protein Subunits; D000072000:NF-KappaB Inhibitor alpha; D000226:Mitochondrial ADP, ATP Translocases; D005982:Glutathione Transferase