Regulation of mitochondrial structure by the actin cytoskeleton

Mitochondria are the powerhouse of the cell and play important roles in multiple cellular processes including cell metabolism, proliferation, and programmed cell death. Mitochondria are double-membrane organelles with the inner membrane folding inward to form cristae. Mitochondria networks undergo dynamic fission and fusion. Deregulation of mitochondrial structure has been linked to perturbed mitochondrial membrane potential and disrupted metabolism, as evidenced in tumorigenesis, neurodegenerative diseases, etc. Actin and its motors-myosins have long been known to generate mechanical forces and participate in short-distance cargo transport. Accumulating knowledge from biochemistry and live cell/electron microscope imaging has demonstrated the role of actin filaments in pre-constricting the mitochondria during fission. Recent studies have suggested the involvement of myosins in cristae maintenance and mitochondria quality control. Here, we review current findings and discuss future directions in the emerging fields of cytoskeletal regulation in cristae formation, mitochondrial dynamics, intracellular transport, and mitocytosis, with focus on the actin cytoskeleton and its motor proteins.