Podcast: What frataxin does in neurological disorder Friedreich ataxia

December 17, 2012 § Leave a comment


Listen to the podcast.

Friedreich ataxia is a rare genetic autosomal recessive disease that damages the nervous system and causes movement problems. In a recent Paper of the Week in the Journal of Biological Chemistry, a team led by Elena Hidalgo at the Universitat Pompeu Fabra in Spain identified a frataxin homolog in the mitochondria of fission yeast. The investigators say their strain of fission yeast missing the frataxin homolog will make a new model for studying the molecular basis for Friedreich ataxia.

The disease is named after the German physician Nikolaus Friedreich, who was the first to describe it in the 1860s.It usually begins in childhood, usually between the ages of 5 and 15, and worsens with age. The condition causes the degeneration of nerve tissue in the spinal cord, especially in the sensory neurons that direct muscle movement of the arms and legs. You can find out more at the Friedreich Ataxia Research Alliance.

The disease involves deficiencies in the protein called frataxin. The protein has homologues in both eukaryotes and prokaryotes but its function is still unresolved.

Structure of frataxin. Image provided by http://en.wikipedia.org/wiki/File:Protein_FXN_PDB_1ekg.png

Structure of frataxin. (Click to see source file.)

Hidalgo and colleagues found that fission yeast cells missing the gene for the protein were sensitive to growth under aerobic conditions, had increased levels of total iron, showed signs of oxidative stress and consumed less oxygen compared to wild-type cells. These signs closely mimic the problems associated with reduced frataxin levels in cells from Friedreich ataxia patients.Proteomic analysis showed that when the yeast cells were missing the frataxin homolog, iron in the cytosol was less readily available causing the activation of a regulator of the iron starvation gene expression program. The data suggest that the frataxin homolog is important for iron and reactive oxygen species homeostasis.

You can hear a podcast discussion about this paper between me and Hidalgo here.

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