Evidence for the presence of ferritin in plant mitochondria

Abstract

In this work, evidence for the presence of ferritins in plant mitochondria is supplied. Mitochondria were isolated from etiolated pea stems and Arabidopsis thaliana cell cultures. The proteins were separated by SDS/PAGE. A protein, with an apparent molecular mass of approximately 25-26 kDa (corresponding to that of ferritin), was cross-reacted with an antibody raised against pea seed ferritin. The mitochondrial ferritin from pea stems was also purified by immunoprecipitation. The purified protein was analyzed by MALDI-TOF mass spectrometry and the results of both mass finger print and peptide fragmentation by post source decay assign the polypeptide sequence to the pea ferritin (P < 0.05). The mitochondrial localization of ferritin was also confirmed by immunocytochemistry experiments on isolated mitochondria and cross-sections of pea stem cells. The possible role of ferritin in oxidative stress of plant mitochondria is discussed.

Ferritin is required for rapid remodeling of the photosynthetic apparatus and minimizes photo‐oxidative stress in response to iron availability in Chlamydomonas reinhardtii

“…Similar results as for whole cells can be seen with isolated chloroplasts (Figure 2), indicating that the ferritin is localized in chloroplasts, as the isolated mitochondria showed no signal for the anti-ferritin antibody. However, it cannot be ruled out completely that ferritin is also localized in the mitochondria, as shown in higher plants (Zancani et al, 2004). The lack of a ferritin signal in isolated mitochondria might be due to a low concentration or modifications of the ferritin that inhibit recognition by our ferritin antibody.…”

“…In mammals, the ferritin complex is localized in the cytosol (Harrison and Arosio, 1996) and is composed of the H and L subunits in a tissuedependent stoichiometry (Galatro and Puntarulo, 2007). The plant ferritin complex is formed and stored in the plastid stroma (Waldo et al, 1995), although mitochondrial localization has recently been described (Zancani et al, 2004), and it is made of only one type of subunit, although evidence for a second subunit has been found (Masuda et al, 2001).…”

Characterization of mitochondrial ferritin in Drosophila

“…Elevated levels of mitochondrial ferritin have been shown to cause cytosolic iron depletion and up-regulation of the transferrin receptor in transfected cell lines (7)(8)(9). Recently, ferritin also was found in plant mitochondria (10).…”

An Iron-induced Nitric Oxide Burst Precedes Ubiquitin-dependent Protein Degradation for Arabidopsis AtFer1 Ferritin Gene Expression

“…Plant ferritins can be found in mitochondria (16), but in contrast to animal cells, they have never been observed in the cyto-* This work was supported by Institut National de la Recherche Agronomique and Centre National de la Recherche Scientifique, Action Concerté e Incitative "Biologie Cellulaire Molé culaire et Structurale" Grant BCMS166 from the Ministè re de l'Education Nationale, de l'Enseignement Supé rieur et de la Recherche. The costs of publication of this article were defrayed in part by the payment of page charges.…”