Mitochondria, the powerhouses of the cell, play a crucial role in energy production through oxidative phosphorylation. Yet, the intricate organization of the protein complexes driving this process has long remained elusive — until now. A recent study published in Science by Florent Waltz and colleagues, including Thalia Salinas-Giegé from the Institute of Molecular Biology of Plants (IBMP), sheds new light on the molecular landscape of mitochondria, revealing unprecedented details of the plant respiratory chain.
Using state-of-the-art cryo-electron tomography, the team visualized mitochondria directly within living cells of Chlamydomonas reinhardtii, a model green alga. This breakthrough approach unveiled the native architecture of the mitochondrial respiratory complexes, capturing their organization in unprecedented detail. The researchers discovered that ATP synthases cluster at the curved tips of cristae (the internal folds of the mitochondrial membrane) while the other respiratory complexes (I, III, and IV) form distinct supercomplexes along the flat membrane regions.
One key finding is the assembly of these complexes into a “respirasome” supercomplex, which orchestrates electron transfer and energy production with remarkable efficiency. By resolving the structure at near-atomic resolution, the team uncovered new insights into how these complexes interact, challenging previous models and opening exciting avenues for understanding mitochondrial function.
This study highlights the ongoing collaboration between Florent Waltz and Philippe Giegé’s team at IBMP, underlining the importance of in situ imaging to capture cellular processes as they occur naturally.
By unmasking the true architecture of the plant respiratory chain, this work not only advances our understanding of energy metabolism but also paves the way for future research into mitochondrial dynamics, with potential applications in agriculture and biotechnology. A remarkable step forward for plant biology!
