Max Planck Institute scientists have discovered that mice deficient in Mfn2 gene die soon after birth. Therefore, the researchers suggest that lack of Mitofusin 2 affects mitochondrial function in other ways besides membrane fusion. The study findings may point to a new treatment for patients with diseases caused by loss of the mitochondrial protein.
Mitofusin 2 and Mitofusin 1, located in the outer membrane of mitochondria, are required for mitochondrial fusion, an important maintenance function in which adjacent organelles join together and exchange contents. Mice studies have revealed that rodents lacking the Mfn1 gene, which encodes Mitofusin 1, nevertheless seem perfectly healthy, but Mfn2-deficient mice die soon after birth. Moreover, mutations in the Mfn2 gene are linked with human diseases, including the peripheral neuropathy, Charcot-Marie-Tooth type 2A.
Researchers investigated mouse heart muscle cells lacking Mfn2 and found that energy metabolism in the cells was impaired compared with healthy and Mfn1-deficient cells. They determined that this process was stalled because of reduced levels of coenzyme Q, a key component of the mitochondrial respiratory chain that generates cellular energy in the form of ATP; and in the absence of Mitofusin 2, many of the enzymes and molecules involved in the pathway that generates precursors of coenzyme Q were decreased, indicating that Mitofusin 2 is required for coenzyme Q production.
The scientists then supplemented the Mfn2-deficient cells with coenzyme Q. This resulted in partial restoration of respiratory chain function. They therefore concluded that coenzyme Q supplements might help treat patients with diseases caused by Mfn2 mutations.
The study is published in 'The Journal of Cell Biology'.