Biology of the Mitochondrial Contact Site and Cristae Organizing System in Trypanosomatids

Abstract

This study describes Mitochondrial Contact Site and Cristae Organizing System (MICOS) in unicellular parasitic protist Trypanosoma brucei. This is the first study of MICOS outside of canonical model organisms belonging to the supergroup Opisthokonta. Nine subunits of the complex were purified and characterized. Their role in cristae biogenesis and interaction with other mitochondrial protein complexes was demonstrated. Further investigation revealed a hierarchical organization of T. brucei MICOS and the existence of two subcomplexes. One of MICOS subunits, TbMic20, facilitates protein import into mitochondrial intermembrane space, which is one of the novel features of T. brucei MICOS. The role of TbMic20 in oxidative protein folding was demonstrated and the mechanism of this process in T. brucei was addressed