A novel route for ATP acquisition by the remnant mitochondria of Encephalitozoon cuniculi
Microsporidia and their remnant mitochondria are energy parasites.
Microsporidians are highly reduced obligate intracellular parasites of other eukaryotes and are an emerging problem infecting victims of HIV/AIDS and other immuno-suppressed patients. As part of their parasitic lifestyle they were long thought to depend on their hosts for energy, but how this was achieved was unknown.
Work published in the 22nd of May edition of Nature by Anastasios Tsaousis, Alina Goldberg, Robert Hirt and Martin Embley has now shown that microsporidia steal ATP from their hosts using surface located adenine nucleotide transporters that are more typically found in bacterial intracellular parasites like Rickettsia and Chlamydia. Moreover, although the canonical function of textbook mitochondria is to make ATP for the host cell, the microsporidian remnant mitochondrion is now an energy parasite too. One of the rickettsia-like proteins has been targeted to the organelle where it can import ATP from the parasite cytosol. Thus, uniquely among eukaryotes, the traditional relationship between mitochondrion and host has been subverted in E. cuniculi, by reductive evolution. Instead of the mitosome providing the parasite cytosol with ATP, the parasite cytosol now provides ATP for the organelle.
The published work is part of a long-term collaboration with Dr Edmund Kunji at the MRC-Dunn Insititute in Cambridge and Dr John Lucocq at Dundee University.
For the full article go to
http://www.nature.com/nature/journal/v453/n7194/abs/nature06903.html
