Scientists solve mystery of how mitochondria pack proteins for peak efficiency
Researchers discovered that mitochondrial proteins self-organize into clusters to reduce physical strain on cell membranes, boosting energy production. The finding could unlock new drug targets for diseases tied to mitochondrial dysfunction, from diabetes to neurodegeneration, while informing biotech strategies for improving cellular energy metabolism in engineered systems.
Originaltitel: Protein-induced membrane strain drives supercomplex formation
<p>Mitochondrial membranes harbor the electron transport chain (ETC) that powers oxidative phosphorylation (OXPHOS) and drives the synthesis of ATP. Yet, under physiological conditions, the OXPHOS proteins operate as higher-order supercomplex (SC) assemblies, although their functional role remains poorly understood and much debated. By combining large-scale atomistic and coarse-grained molecular simulations with analysis of cryo-electron microscopic data and statistical as well as kinetic models, we show here that the formation of the mammalian I/III<sub>2</sub> supercomplex reduces the molecular strain of inner mitochondrial membranes by altering the local membrane thickness and leading to an accumulation of both cardiolipin and quinone around specific regions of the SC. We find that the SC assembly also affects the global motion of the individual ETC proteins with possible functional consequences. On a general level, our findings suggest that molecular crowding and strain effects provide a thermodynamic driving force for the SC formation, with a possible flux enhancement in crowded biological membranes under constrained respiratory conditions.</p>