This family contains proteins that have a domain related to the globular C-terminus of Frataxin the protein that is mutated in Friedreich's ataxia. This domain is found in a family of bacterial proteins. The function of this domain is currently unknown. It has been suggested that this family is involved in iron transport.
The eukaryotic proteins in this entry include frataxin, the protein that is mutated in Friedreich's ataxia [ (PUBMED:8931268) ], and related sequences. Friedreich's ataxia is a progressive neurodegenerative disorder caused by loss of function mutations in the gene encoding frataxin (FRDA). Frataxin mRNA is predominantly expressed in tissues with a high metabolic rate (including liver, kidney, brown fat and heart). Mouse and yeast frataxin homologues contain a potential N-terminal mitochondrial targeting sequence, and human frataxin has been observed to co-localise with a mitochondrial protein. Furthermore, disruption of the yeast gene has been shown to result in mitochondrial dysfunction. Friedreich's ataxia is thus believed to be a mitochondrial disease caused by a mutation in the nuclear genome (specifically, expansion of an intronic GAA triplet repeat) [ (PUBMED:8596916) (PUBMED:8815938) (PUBMED:9241270) ].
The bacterial proteins in this entry are iron-sulphur cluster (FeS) metabolism CyaY proteins homologous to eukaryotic frataxin. Partial Phylogenetic Profiling [ (PUBMED:16930487) ] suggests that CyaY most likely functions as part of the ISC system for FeS cluster biosynthesis, and is supported by expermimental data in some species [ (PUBMED:16603772) (PUBMED:16428423) ].
There are 4591 Frataxin_Cyay domains in 4591 proteins in SMART's nrdb database.
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Evolution (species in which this domain is found)
Taxonomic distribution of proteins containing Frataxin_Cyay domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with Frataxin_Cyay domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing Frataxin_Cyay domain in the selected taxonomic class.
Friedreich's ataxia protein: phylogenetic evidence for mitochondrial dysfunction.
Trends Neurosci. 1996; 19: 465-8
Display abstract
Friedreich's ataxia is the most common inherited spinocerebellar ataxia. A decadeof linkage and physical mapping studies have culminated in the identification of the Friedreich's ataxia gene. The presence of homologues in purple bacterialgenomes, but not in other bacteria, allows us to infer a mitochondrial locationfor frataxin (Friedreich's ataxia protein) on the basis of bacterial phylogeny.Frataxin possesses a non-globular N-terminus domain providing a candidatemitochondrial targeting peptide. Clues to the function of frataxin are providedby the mitochondrial location, a clinically similar ataxia with vitamin Edeficiency, and certain neuropathies with mitochondrial DNA instability caused bymutations in nuclear genes.
