Figure 1.

Respiratory chain and mitochondrial dynamics. (A) Respiratory chain. Electrons and protons flow through complexes of the respiratory chain in oxidative phosphorylation. (B) Mitophagy is mediated by PINK1, PARKIN, and P-62 proteins, which recruit the protein LC3-II and form the autophagosome for cell degradation. (C) Mitochondrial fission is mediated by the protein Drp1, which is recruited from the cytosol to interact with the protein fis1 in the mitochondrial outer membrane, forming constriction points that lead to mitochondrial fission. (D) Mitochondrial fusion requires the action of the Opa1 protein on the inner mitochondrial membrane and the action of Mfn1 and Mfn2 proteins in the outer mitochondrial membrane, promoting the fusion of juxtaposed mitochondrial membranes.