Probes to monitor mitochondrial dynamics. The major molecular players regulating these functions are symbolized within mitochondria. Key imaging-based approaches are listed in the grey box. OPA1, dynamin-like GTPase optic atrophy 1; MFNs, mitofusin 1 and mitofusin 2; DRP1, dynamin-related protein 1; IMM, inner mitochondrial membrane; OMM, outer mitochondrial membrane; ΔΨ, membrane potential difference; FPs, fluorescent proteins; and GE, genetically-encoded. The figure was generated with elements provided in the Servier Medical Art depository (https://smart.servier.com/) and are licensed under a Creative Commons Attribution 3.0 Unported License (CC BY 3.0).