A massive supercomplex induces membrane curvature for cellular respiration

Researchers from the Department of Biochemistry and Biophysics at Stockholm University, based at Science for Life Laboratory, together with collaborators from Helsinki University and UCL, have published a study that highlights the composition of a complete respiratory supercomplex, and how it shapes the membrane in order to support energy conversion for cellular life.

The structure of the supercomplex
The structure of the supercomplex.

Assoc Professor Alexey Amunts and his co-authors have studied the cellular respiration process inside the model organism Tetrahymena thermophila - a free-living eukaryote found in lakes. Inside eukaryotes are mitochondria, organelles which convert foodstuff into the chemical energy essential for life through the process of cellular respiration. The cellular respiration is driven by four respiratory complexes in the inner mitochondrial membrane. 

The study published in Nature identified that in Tetrahymena thermophila, all four respiratory complexes are associated together, forming a single supercomplex. The supercomplex actively contributes to mitochondrial membrane curvature induction for energy conversion. Thus, it shapes the macroscopic architecture of mitochondria, which ultimately optimizes the synthesis of ATP, a chemical form of energy. The work also highlights how the evolution of protein subunits of respiratory complexes has led to the supercomplex assembly.

The research was funded by the ERC, the Knut and Alice Wallenberg Foundation and the SSF Future Leaders program.

Get a deeper understanding of the study in this video.

Publication: ”Structural basis of mitochondrial membrane bending by the I–II–III2–IV2 supercomplex.” Nature, volume 615, pages 934–938 (2023) 

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