Figure 3.

Mitochondrial dynamics. (A) Shows joining of mitochondria by the process of fusion, which is mediated by the OMM fusion protein isoforms, Mfn1 and Mfn2, and the inner mitochondrial (IMM) fusion protein OPA1 (labelled in yellow and green respectively). Fusion causes the intermixing of the contents of the mitochondrial matrix of two discrete mitochondria. This process of complementation results in a healthier, elongated, single mitochondrion. (B) Shows the division of mitochondria by the process of fission. Fission is mediated by Drp1, which is recruited to the mitochondria from the cytosol after post-translational activation, often by phosphorylation at serine 616. OMM adapter proteins, such as MFF, Fis1, MiD49 and MiD51, focus on multimeric Drp1 assembly. A Drp1-enriched fission ring surrounds the mitochondria forming a ring-like structure which cleaves the organelle causing fission.