IκB-α, the NF-κB Inhibitory Subunit, Interacts with ANT, the Mitochondrial ATP/ADP Translocator

Virginie Bottero,Franca Rossi,Michel Samson,Mireille Mari,Paul Hofman,Jean-François Peyron

doi:10.1074/jbc.m005850200

Virginie Bottero, Franca Rossi + Show 4 more

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https://doi.org/10.1074/jbc.m005850200

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Journal: Journal of Biological Chemistry	Publication Date: Jun 1, 2001
Citations: 86	License type: cc-by

Affiliation: Hôpital Pasteur, Inserm

Abstract

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.

Highlights

The transcription factor NF-␬B regulates a wide set of genes involved in the establishment of many cellular processes that control cell activation, proliferation, and apoptosis
We show that I␬B-␣1⁄7NF-␬B complexes are present in the mitochondrial intermembrane space via interaction of the N-terminal domain of I␬B-␣ with the internal membrane protein ANT
Immunoelectron microscopy allowed the unambiguous demonstration of I␬B-␣1⁄7NF-␬B complexes in the mitochondrial intermembrane space

Summary

Introduction

The transcription factor NF-␬B regulates a wide set of genes involved in the establishment of many cellular processes that control cell activation, proliferation, and apoptosis. I␬B inhibitory subunits integrate NF-␬B activation signals through phosphorylation and ubiquitination of its N-terminal domain. I␬B␣1⁄7NF-␬B appeared to be released from mitochondria upon the induction of apoptosis by engagement of the Fas receptor These data suggest that the mitochondrial I␬B-␣1⁄7NF-␬B pool participates in the regulation of apoptosis. The N-terminal domain of I␬B-␣ appears to integrate NF-␬B activation signals We used this regulatory domain as a bait in a yeast two-hybrid screening of a Jurkat cDNA library to search for protein interactors and potential regulators of NF-␬B activation. ANT is a central component of the mitochondria permeability transition pore [11] The opening of this pore, during induction of apoptosis allows the release of molecules, such as caspases or apoptosis-inducing factor, which are important to amplify the cell suicide response. The possible functional importance of the I␬B-␣/ANT interaction in the context of regulation of apoptosis is discussed

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