You are currently viewing the abstract.
View Full TextLog in to view the full text
AAAS login provides access to Science for AAAS members, and access to other journals in the Science family to users who have purchased individual subscriptions.
Register for free to read this article
As a service to the community, this article is available for free. Existing users log in.
More options
Download and print this article for your personal scholarly, research, and educational use.
Buy a single issue of Science for just $15 USD.
Keeping Mitochondria in the Pink
Pink1 is a mitochondrial kinase, and loss of Pink1 function in flies and mice results in the accumulation of inefficient mitochondria. In a screen for modifiers of the Parkinson-associated gene, pink1, Vos et al. (p. 1306, published online 10 May; see the Perspective by Bhalerao and Clandinin) identified the fruit fly homolog of UBIAD1, “Heix.” UBIAD1 was localized in mitochondria and was able to convert vitamin K1 into vitamin K2/menaquinone (MK-n, n the number of prenylgroups). In bacteria, vitamin K2/MK-n acts as an electron carrier in the membrane and, similarly, in Drosophila, mitochondrial vitamin K2 appeared to act as an electron carrier to facilitate adenosine triphosphate production. Fruit flies that lack heix showed severe mitochondrial defects that could be rescued by administering vitamin K2.
Abstract
Human UBIAD1 localizes to mitochondria and converts vitamin K1 to vitamin K2. Vitamin K2 is best known as a cofactor in blood coagulation, but in bacteria it is a membrane-bound electron carrier. Whether vitamin K2 exerts a similar carrier function in eukaryotic cells is unknown. We identified Drosophila UBIAD1/Heix as a modifier of pink1, a gene mutated in Parkinson’s disease that affects mitochondrial function. We found that vitamin K2 was necessary and sufficient to transfer electrons in Drosophila mitochondria. Heix mutants showed severe mitochondrial defects that were rescued by vitamin K2, and, similar to ubiquinone, vitamin K2 transferred electrons in Drosophila mitochondria, resulting in more efficient adenosine triphosphate (ATP) production. Thus, mitochondrial dysfunction was rescued by vitamin K2 that serves as a mitochondrial electron carrier, helping to maintain normal ATP production.
