title: Voltage-dependent anion channel 1-based peptides interact with Bcl-2 to prevent antiapoptotic activity.
abstract: The antiapoptotic proteins of the Bcl-2 family are expressed at high levels in many types of cancer. However, the mechanism by which Bcl-2 family proteins regulate apoptosis is not fully understood. Here, we demonstrate the interaction of Bcl-2 with the outer mitochondrial membrane protein, voltage-dependent anion channel 1 (VDAC1). A direct interaction of Bcl-2 with bilayer-reconstituted purified VDAC was demonstrated, with Bcl-2 decreasing channel conductance. Expression of Bcl-2-GFP prevented apoptosis in cells expressing native but not certain VDAC1 mutants. VDAC1 sequences and amino acid residues important for interaction with Bcl-2 were defined through site-directed mutagenesis. Synthetic peptides corresponding to the VDAC1 N-terminal region and selected sequences bound specifically, in a concentration- and time-dependent manner, to immobilized Bcl-2, as revealed by the real-time surface plasmon resonance. Moreover, expression of the VDAC1-based peptides in cells over-expressing Bcl-2 prevented Bcl-2-mediated protection against staurosporine-induced apoptotic cell death. Similarly, a cell-permeable VDAC1-based synthetic peptide was also found to prevent Bcl-2-GFP-mediated protection against apoptosis. These results point to Bcl-2 as promoting tumor cell survival through binding to VDAC1, thereby inhibiting cytochrome c release and apoptotic cell death. Moreover, these findings suggest that interfering with the binding of Bcl-2 to mitochondria by VDAC1-based peptides may serve to potentiate the efficacy of conventional chemotherapeutic agents.
authors.affiliation: Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Nir
authors.initials: N
authors.lastname: Arbel
authors.forename: Varda
authors.initials: V
authors.lastname: Shoshan-Barmatz
mesh_terms: D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D004553:Electric Conductivity; D004594:Electrophysiology; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012756:Sheep; D020349:Surface Plasmon Resonance; D050995:Voltage-Dependent Anion Channel 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D019253:Proto-Oncogene Proteins c-bcl-2; D050995:Voltage-Dependent Anion Channel 1