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Incoming links: Mitochondrial fission-fusion cycle
Hsiuchen Chen Created 2026-10-20 Updated 2026-11-05
Researcher in mitochondrial dynamics. Chen and collaborators investigated coordinated action of Mfn1 and Mfn2 in mitochondrial fission-fusion cycle, connecting organelle remodeling with embryonic development.[ref]
Mitochondrial fusion 2026-11-05
Mitochondrial fusion is the joining of previously separate mitochondria, allowing their internal contents to mix. Because each mitochondrion has two boundary cell membranes, complete mitochondrial fusion requires joining both the outer and the inner mitochondrial membrane. Together with mitochondrial fission-fusion cycle, it makes mitochondria a changing network rather than a fixed collection of bean-shaped objects.
A useful experiment distinguishes joining from mere contact. Hsiuchen Chen and colleagues mixed mouse cells carrying differently coloured fluorescent proteins targeted to the mitochondrial interior, then fused the cells so both labelled populations shared one cytoplasm. Appearance of both colours within the same mitochondria reported content mixing. Loss of either mitofusin Mfn1 or Mfn2 reduced this mixing and produced fragmented mitochondria; restoring the missing protein rescued the defect. Mitochondrial fusion therefore has a measurable molecular requirement and permits exchange within the mitochondrial population.[ref]
Mitofusins Mfn1 and Mfn2 coordinately regulate mitochondrial fusion and are essential for embryonic development by Hsiuchen Chen and others. Results, Mitochondrial fusion is severely reduced in mutant cells; polyethylene-glycol cell-fusion assay and rescue experiments
The mitochondrial fission-fusion cycle is continuous remodeling of a mitochondrial population by division and merger. In mammalian biological cells, mitofusins promote fusion of outer mitochondrial membranes, while OPA1 supports fusion of inner mitochondrial membranes. Fusion mixes matrix contents and permits functional complementation between mitochondria. Genetic disruption and rescue of mitofusins demonstrated their requirement for normal mitochondrial fusion.[ref]
Mitofusins Mfn1 and Mfn2 coordinately regulate mitochondrial fusion and are essential for embryonic development by Hsiuchen Chen and others. Abstract and Results: mitofusin loss, fragmented mitochondria and rescue
For fission, recruited Drp1 assembles at constrictions and uses GTP-dependent remodeling to help divide the organelle.[ref]
Dynamin-related protein Drp1 is required for mitochondrial division in mammalian cells by Elena Smirnova and others. Abstract and Results: Drp1 recruitment and division defects
The balance controls network shape, distribution and quality control. Division can help distribute mitochondria to daughter biological cells and segregate damaged portions for mitophagy; fusion can restore mixed contents. These are regulated competing events in a network, not an obligatory synchronized sequence that every mitochondrion completes on a fixed timetable.