Fig. 6: Identification of mitochondrial “spherical crista”.

A Representative FIB-SEM image of mitochondria in HeLa Mic10 KO cells (left panel). 3D reconstruction and segmentation of mitochondrion showing spherical crista from FIB-SEM were completed by using 3D-IMOD software. White, mitochondrial outer membrane; cyan, mitochondrial IBM; purple red, the spherical crista. B Quantification of the “spherical crista” in mitochondria of control and Mic10 KO HeLa cells. “others” means “other types of crista except for spherical crista” (n = 100 cristae). Statistical significance was assessed from the student’s t-test; error bars indicate the means ± SD of three independent experiments, ***p < 0.001 versus control. C The specimen from HCT116 OPA1 KO cells was analyzed and imaged by FIB-SEM. 3D reconstruction and segmentation of mitochondrion containing spherical crista were performed by using 3D-IMOD software. White, mitochondrial outer membrane; cyan, IBM; purple red, the spherical crista. D The samples of HCT116 Mic10-OPA1 DKO cells were analyzed and imaged by FIB-SEM. 3D reconstruction and segmentation of mitochondrion showing two contacted spherical cristae were completed using 3D-IMOD software. White, mitochondrial outer membrane; cyan, mitochondrial IBM; purple red, the spherical crista. E Quantification of the spherical crista in mitochondria of control, OPA1 KO, and Mic10-OPA1 double knockout (DKO) HCT116 cells (n = 100 cristae). “others” means “other types of crista except for spherical crista”. Statistical significance was assessed from the student’s t-test; error bars indicate the means ± SD of three independent experiments, ***p < 0.001 versus control. F The mode of the spherical crista formation. Two mitochondria contact and process mitochondrial outer membrane fusion, the small mitochondrion is then engulfed into the bigger mitochondria, and detaches from the IBM of the bigger mitochondrion to form the spherical crista. G, H Representative FIB-SEM images of mitochondria (G, H) in HCT116 Mic10-OPA1 DKO cells. 3D reconstruction and segmentation of mitochondrion showing the spherical crista were completed using 3D-IMOD software. White, mitochondrial outer membrane; cyan, mitochondrial IBM; purple red, the spherical crista.