Figure 1.

A schematic diagram of mitochondrial dynamics. Human mitochondria undergo constant fusion and fission dynamics. The fusion of the OMM is mediated by Mfn1/2. PA generated by MitoPLD promotes fusion of the OMM. CL and Opa1 coordinate IMM fusion. Mic60 also interacts with Opa1. ER tubules mark sites of fission. During mitochondrial fission, Drp1 is recruited to mitochondria by receptors such as Fis1, Mid49, Mid51 and Mff. GDAP1 and sacsin are two additional proteins localized in the OMM that facilitate fission. Drp1 activity is regulated by posttranslational modifications such as phosphorylation and ubiquitination. The preconstriction process is completed by actin filaments, and Drp1 performs mitochondrial scission. Lipids, including ceramides, PA and DAG, participate in mitochondrial fission. PA, phosphatidic acid; OMM, outer mitochondrial membrane; CL, cardiolipin; Drp1, dynamin-related protein 1; DAG, diacylglycerol; ER, endoplasmic reticulum.