VDAC3 interactomic analysis.

VDACs (voltage-dependent anion channel), are a small family of proteins of the mitochondrial outer membrane, considered as gatekeeper of mitochondrial metabolites and thereby controlling cross-talk between mitochondria and the rest of the cell (1-2). VDAC is also a key player in mitochondria-mediated apoptosis (3). In addition, VDAC appears to be a convergence point for a variety of cell survival and cell death signals mediated by its association with various ligands and proteins. There are many reports about the involvement of VDAC in several diseases (4). Understanding what proteins are able to interact with VDACs (interactome) is critical for deciphering how this channel can perform such a variety of important functions (5). Since identification of interacting proteins is very difficult due to complexity of cellular protein extracts, we applied TAP-tag technology (Tandem Affinity Purification with tag) to the analysis of VDAC interactomes. In particular we have investigated binding partners of human VDAC3 (human voltage dependent channel isoform 3) (6), the least known and the most intriguing among the various porin isoforms, with a stable HeLa line expressing YFP-tev-HIS-VDAC3. After cell lysis, the proteins interacting with VDAC3 were purified by two affinity chromatographies. Finally, the protein complex was analysed by proteomics. A list of interacting proteins has thus been defined and this will be used to establish functional roles of VDAC3.