Fig. 3: Mitochondrial cristae types and dynamic events.
From: OPA1 and MICOS Regulate mitochondrial crista dynamics and formation
A, B HeLa (A) and COS-7 (B) cells were stained with MitoTracker Green (250 nM, 15 min), and then imaged by Hessian-SIM. The white arrows marked the mitochondrial cristae lacking crista junction. C–F Mitochondrial cristae in HeLa (C) or HCT116 (E) cells were analyzed and imaged by transmission electron microscopy (TEM), and the representative image of mitochondrial ultrastructure was drawn. The red numbers represent the different types of mitochondrial cristae morphology. “1” represents mitochondrial crista with one crista junction (CJ), “2” represents mitochondrial crista containing two CJs, “3” represents mitochondrial crista lacking CJs. Then, the number of HeLa (D) or HCT116 (F) mitochondrial cristae types were counted (three independent experiments, 100 mitochondria cristae for each experiment). G HeLa cells were fixed, filtrated, polymerized, and embedded in EPON 812 resin, the specimen of 70 nm sections was then imaged using Fei Tecnai Spirit Transmission Microscope. There-dimensional (3D) reconstruction and segmentation of mitochondria were completed using 3D-IMOD software. Cyan: mitochondrial crista containing CJ; red, mitochondrial crista lacking CJ. H–J HeLa mitochondrial cristae were analyzed and imaged by TEM, and the representative images of mitochondrial ultrastructure were drawn. The indicated mitochondrial cristae dynamic events were displayed, the red arrows in the drawing picture indicate the cristae contacting IBM (H), crista containing two CJs (I), or crista–crista contact site (J). K The models of mitochondrial cristae dynamics. 1. Mitochondrial cristae division: one crista splits into two independent cristae; 2. Mitochondrial cristae fusion: two cristae fused into one crista; 3. Mitochondrial cristae shorten: the length of cristae is shortened; 4. Mitochondrial growth and elongation: crista undergoes growth and elongation; 5. Mitochondrial crista detachment: crista is detached from IBM, meanwhile, lost a Cj; 6. Mitochondrial cristae network: cristae can fuse with each other to form a network structure. 7. Mitochondrial cristae communication inter-mitochondria: cristae contacts and communicates with each other between two mitochondria.
