DNM1L and sarcopenia: Abnormalities in mitochondrial morphology observed in sarcopenia are a direct consequence of the dysregulation of key proteins involved in mitochondrial dynamics, including the fusion proteins, mitofusins 1 and 2 (MFN1 and MFN2) and optic atrophy protein 1 (OPA1), and the fission proteins, mitochondrial fission factor (MFF) and dynamin-related protein 1 (DRP1).