Scientists are one step closer to understanding a progressive neurodegenerative disease thanks to a study into the role of the protein frataxin in iron transport in the body.

In Friedreich's ataxia (FRDA), an inherited disorder that affects about 1 in 50,000 people, the body is unable to make frataxin. The resulting protein deficiency affects the ability of cells to control and utilise iron, with debilitating consequences. 

Timothy Stemmler at Wayne State University, US, and his colleagues in the US and Mexico, investigated frataxin's role in the production of heme - an iron-containing protein cofactor that controls cellular processes ranging from energy production to oxygen transport. Using a combination of x-ray absorption and nuclear magnetic resonance spectroscopies, the team showed that frataxin operates as a molecular chaperone to iron, delivering the metal to ferrochelatase, the enzyme involved in assembling heme.

Andrew Dancis, an expert in iron transport at the University of Pennsylvania, US, explained that the iron delivery step in the ferrochelatase synthesis of heme has been completely mysterious until now. 'Frataxin is in the right place to play a role in this process,' he said. 'Stemmler sheds light on this process by defining the human ferrochelatase binding surface with iron and frataxin, and by proposing a pathway for the iron delivery.' 

Stemmler suggested that, 'if we can understand all the steps involved in the different cellular iron regulation pathways at the protein level, we can provide a universal understanding of how cells control the chemistry performed by this highly reactive element. This insight should help not only in treating FRDA,' he continued, 'but the growing number of metal regulation related human disorders as well.' 

Kathryn S Lees