The effects of frataxin silencing in HeLa cells are rescued by the expression of human mitochondrial ferritin.
Frataxin is a ubiquitous mitochondrial iron-binding protein involved in the biosynthesis of Fe/S clusters and heme. Its deficiency causes Friedreich's ataxia, a severe neurodegenerative disease. Mitochondrial ferritin is another major iron-binding protein, abundant in the testis and in sideroblasts from patients with sideroblastic anemia. We previously showed that its expression rescued the defects caused by frataxin deficiency in the yeast. To verify if this occurs also in mammals, we silenced frataxin in HeLa cells. This caused a reduction of growth, inhibition of the activity of aconitase and superoxide dismutase-2 and reduction of cytosolic ferritins without alteration of mitochondrial iron content. None of these effects were evident when silencing was done in cells expressing mitochondrial ferritin. These data indicate that frataxin has some roles in controlling the balance between different mitochondrial iron pools that are partially in common with those of mitochondrial ferritin.
Zanella
Isabella
I
Dipartimento Materno Infantile e Tecnologie Biomediche, Università di Brescia, Viale Europa 11, Brescia, Italy.
Derosas
Manuela
M
Corrado
Marcella
M
Cocco
Emiliano
E
Cavadini
Patrizia
P
Biasiotto
Giorgio
G
Poli
Maura
M
Verardi
Rosanna
R
Arosio
Paolo
P
D001052:Apoferritins / Q000235:genetics*; D049109:Cell Proliferation / Q000187:drug effects*; D002950:Citrate (si)-Synthase / Q000378:metabolism; D050259:Genes, Mitochondrial; D006367:HeLa Cells; D006801:Humans; D007501:Iron / Q000378:metabolism; D033862:Iron-Binding Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D034622:RNA Interference / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology*; D013385:Succinate Dehydrogenase / Q000378:metabolism; D014162:Transfection; D000096923:Frataxin
D001052:Apoferritins; D002950:Citrate (si)-Synthase; D007501:Iron; D033862:Iron-Binding Proteins; D034741:RNA, Small Interfering; D013385:Succinate Dehydrogenase; D000096923:Frataxin