Mitochondrial Cristae Shape Determines Respiratory Chain Supercomplexes Assembly and Respiratory Efficiency

TLDR

Respiratory chain complexes form supercomplexes within mitochondrial cristae. The study examines how cristae shape influences supercomplex assembly and mitochondrial respiratory efficiency. Genetic and apoptotic alterations of cristae structure modulate supercomplex assembly and activity without affecting protein synthesis or outer membrane permeabilization. The data show that mitochondrial respiratory efficiency and cell growth depend on cristae shape, linking supercomplex assembly to membrane morphology.

Abstract

Respiratory chain complexes assemble into functional quaternary structures called supercomplexes (RCS) within the folds of the inner mitochondrial membrane, or cristae. Here, we investigate the relationship between respiratory function and mitochondrial ultrastructure and provide evidence that cristae shape determines the assembly and stability of RCS and hence mitochondrial respiratory efficiency. Genetic and apoptotic manipulations of cristae structure affect assembly and activity of RCS in vitro and in vivo, independently of changes to mitochondrial protein synthesis or apoptotic outer mitochondrial membrane permeabilization. We demonstrate that, accordingly, the efficiency of mitochondria-dependent cell growth depends on cristae shape. Thus, RCS assembly emerges as a link between membrane morphology and function.