Precursor Protein but not Intermediate and Mature Protein of Frataxin Directly Interacts with a 54 kDa Protein of Mitochondrial Processing Peptidase

Friedreich’s ataxia (FRDA) is an Autosomal recessive neurodegenerative disorder caused by GAA triplet repeat expansion or point mutation in FRDA gene. This gene codes for a protein called frataxin which shows reduced expression in FRDA patients. The aim of the study was to unravel the function of frataxin. The function of frataxin is not known yet and is a mystery. In order to find the function of an unknown protein it is better to find out interacting partner protein. Interacting partner proteins of frataxin were captured by immunoprecipitation and subsequently visualized in the form of band on western blotting. Result and significance: While unraveling the frataxin function by capturing interacting partner proteins through immunoprecipitation, a novel protein of 54 kDa was identified beside previously known 30 kDa and 18 kDa precursor and mature proteins of frataxin. Immunohistochemistry of normal human brains sections revealed the perfect specificity of frataxin protein that we used for the immunoprecipitation. Given that 30 kDa and18 kDa frataxin proteins previously reported, we report here the presence of a 54 kDa protein which could be an interacting partner protein of frataxin. Further investigations are required to identify type of protein and its relevant role in the appropriate functioning of frataxin.