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
New to topics? Read the docs here!