VDAC1-interacting proteins: binding site mapping and their derived peptides induce apoptosis and multifaceted cellular effects.

The mitochondrial voltage-dependent anion channel-1 (VDAC1) protein plays a central role in regulating mitochondrial metabolism, energy production, and apoptosis. VDAC1 interacts with over 100 proteins across the cytosol, endoplasmic reticulum, plasma membrane, and mitochondrial membranes. These interactions coordinate metabolism, cell death, and signal transduction, integrating mitochondrial and cellular functions. To identify VDAC1 binding sites, we designed a peptide array of 768 peptides from 19 selected VDAC1-interacting proteins. We focused on three partners: GAPDH, gelsolin, and actin. Their VDAC1-binding sequences as peptides interacted with purified VDAC1 and, as cell-penetrating peptides, induced cell death, and elevated intracellular Ca⁺ and ROS levels. Despite sequence diversity, the peptides converged on enhancing transcription factors p53 and c-Jun, upregulating VDAC1, promoting its oligomerization, and triggering apoptosis. Other effects related to their originated protein's function include no significant effect of the GAPDH-derived peptide on its catalytic activity, indicating its effects are independent of glycolysis. The gelsolin-derived peptide altered actin organization, increasing filopodia and focal adhesion, and actin-derived peptides reduced actin, gelsolin, and tubulin expression. This study is the first to identify VDAC1 binding sites on 19 interacting partners and to demonstrate their use as cell-penetrating peptides to modulate the VDAC1 network. These findings highlight VDAC1's multifaceted regulatory role and offer a novel approach for targeting VDAC1-protein interactions for therapeutic purposes.