A membrane-disruptive action of VBIT-4 challenges its role as a widely used VDAC1 oligomerization inhibitor.

VBIT-4 disrupts membranes and induces cytotoxicity independently of VDAC1 oligomerization at micromolar concentrations.

• Why it matters: Understanding VDAC1's role in mitochondrial processes is limited by the lack of specific inhibitors, and VBIT-4 has been widely used as such, necessitating validation of its mechanism.
• What they did: Researchers used high-speed atomic force microscopy, electrophysiology, thermophoresis, and molecular dynamics to analyze VBIT-4's effects on VDAC1 and membranes, testing 10 μM concentrations.
• The result: VBIT-4 does not modify VDAC1 organization or channel function but instead destabilizes lipid membranes and causes VDAC1-independent cytotoxicity, challenging its use as a specific VDAC1 inhibitor.