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Assessment of Open Probability of the Mitochondrial Permeability Transition Pore in the Setting of Coenzyme Q Excess
Published on: June 1, 2022
A pore is a pore is a pore (or a hub?): VDAC oligomerization in mitochondrial connectivity and modulation
Vito De Pinto1, Giuseppe Battiato1, Stefano Conti-Nibali1
1Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy.
Abstract:
For decades, the voltage-dependent anion-selective channel (VDAC), formerly known as the mitochondrial porin, was considered a simple pore enabling nearly free permeability across the outer mitochondrial membrane. This simplified view has been progressively dismantled through the discovery of three mammalian isoforms (VDAC1, VDAC2, and VDAC3) with the gradual attribution, often serendipitous, of diverse cellular roles beyond passive metabolite exchange. Recent advances in cryo-electron microscopy have catalyzed a breakthrough in VDAC research. Three converging lines of evidence are reshaping our understanding: (a) high-resolution structures of VDAC within its native protein complexes; (b) discovery of unexpected functions, including phospholipid scrambling and regulation of outer membrane permeabilization through higher-order oligomeric assemblies; and (c) structural determination of VDAC interactions with macromolecules, as well as small-molecule modulators. Collectively, these insights have strengthened the consideration of VDAC as a multifunctional signaling hub and therapeutic target, with emerging small molecules and peptides designed to modulate gating, oligomerization, and interfering with interacting partners. The aim of this review is to summarize current structural, functional, and pharmacological advances in VDAC biology, emphasizing how oligomerization dynamics and isoform specificity orchestrate mitochondrial behavior and offering perspectives on therapeutic strategies for diseases driven by mitochondrial dysfunction.
Insights
Voltage-dependent anion-selective channels (VDACs) are now understood as multifunctional signaling hubs, not just simple pores. Their complex roles and structures offer new therapeutic targets for mitochondrial diseases.
Area of Science:
- Mitochondrial Biology
- Structural Biology
- Molecular Medicine
Background:
- The voltage-dependent anion-selective channel (VDAC) was historically viewed as a passive pore in the outer mitochondrial membrane.
- Discovery of three mammalian isoforms (VDAC1-3) revealed diverse cellular functions beyond metabolite transport.
Purpose of the Study:
- To review recent structural, functional, and pharmacological advances in VDAC biology.
- To highlight VDAC's role as a multifunctional signaling hub and therapeutic target.
- To emphasize VDAC oligomerization dynamics and isoform specificity in mitochondrial regulation.
Main Methods:
- Cryo-electron microscopy for high-resolution VDAC structure determination within native complexes.
- Investigation of VDAC's phospholipid scrambling and outer membrane permeabilization functions.
- Structural analysis of VDAC interactions with small molecules and macromolecules.
Main Results:
- High-resolution structures reveal VDACs in native protein complexes.
- VDACs exhibit novel functions like phospholipid scrambling and regulating outer membrane permeabilization via oligomers.
- Interactions with small molecules and macromolecules are structurally defined.
Conclusions:
- VDACs are multifunctional signaling hubs with significant therapeutic potential.
- Oligomerization dynamics and isoform specificity are key to VDAC's role in mitochondrial function.
- Emerging VDAC modulators offer therapeutic strategies for mitochondrial dysfunction-related diseases.
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