Figure 1.

The molecular machinery of mitochondrial network regulation. On the left, the mitochondrial fission process in which several proteins are involved. Dynamin-related protein 1 (DRP1), localized in the cytosol, is recruited by fission 1 protein (FIS1), MID49/51, mitochondrial fission factor (MFF) and mitochondrial fission process protein 1 (MTFP1) to the mitochondrial surface, where it forms a membrane constriction ring. On the right, the mitochondrial fusion process that involves optic atrophy gene 1 (OPA1), which mediates fusion of the inner mitochondrial membrane, and mitofusin 1/2 (MFN1/2), which enhance the fusion of the outer mitochondrial membrane. In mammals, FIS1 can act as a fusion machinery inhibitor by binding to OPA1 and MFN1/2 and blocking their activity.