The mitochondrial protein frataxin is essential for heme biosynthesis in plants

MALIANDI, M. V.; BUSI, M. V.; TUROWSKI, V.; LEADEN, L; ARAYA, A.; DIEGO FABIAN GOMEZ CASATI

FEBS JOURNAL

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Cambridge; Año: 2011 vol. 278 p. 470 - 481

1742-464X

Frataxin, a conserved mitochondrial protein implicated in cellular iron homeostasis, has been involved as the iron chaperone that delivers iron for Fe–S cluster and heme biosynthesis. The role of frataxin in Fe metabolism remains unclear, especially in photosynthetic organisms. In previous work, we found that frataxin deficiency in Arabidopsis results in decreased activity of Fe-S proteins aconitase and succinate dehydrogenase despite the increased expression of the respective genes, indicating an important role for AtFH in the plants. In this work, we explore the hypothesis that AtFH can participate in heme formation. For this purpose, we used two different deficient lines, one, atfh-1, with a T-DNA insertion in the 5’ untranslated region of the gene and the other, as-AtFH, expressing the antisense version of the frataxin gene. AtFH deficient plants present alteration in several transcripts from the heme biosynthetic route with a decrease in total heme content and a deficiency of catalase activity. The catalase activity was rescued by exogenous hemin, indicating that AtFH, besides their role in protecting bioavailable iron within mitochondria and the synthesis of Fe-S groups, also plays a role in the biogenesis of heme group. Data presented here substantiate the hypothesis that AtFH would have a major role in heme production as an “iron chaperone” for ferrochelatase also is involved in the biogenesis of plant heme proteins such as catalase. These results indicate that AtFH deficiency affects the catalytic activity of catalase resulting from a heme deficiency and suggests that AtFH could be involved in protect bioavailable iron within cells.