Mitochondrial cristae biogenesis coordinates with ETC complex IV assembly during Drosophila maturation

Mitochondrial cristae contain electron transport chain (ETC) complexes and are distinct from the inner boundary membrane (IBM) in both protein composition and function. While many details of mitochondrial membrane structure are known, the processes governing cristae biogenesis, including the organization of lipid membranes and assembly of proteins encoded by both nuclear and mitochondrial DNA, remain obscure. We followed cristae biogenesis in situ upon Drosophila eclosion using serial-section electron tomography and revealed that the morphogenesis of lamellar cristae coordinates with ETC complex IV assembly. The membrane morphogenesis and gain-of-function were intricately co-evolved during cristae biogenesis. Marf-knockdown flies formed lamellar cristae containing ATP synthase and functional COX. However, OPA1-knockdown flies showed impaired cristae biogenesis. Overall, this study revealed the multilevel coordination of protein-coupled membrane morphogenesis in building functional cristae.