"Microsporidia are tiny obligate intracellular parasites of other eukaryotes including patients with HIV/AIDS. Despite their importance, detailed knowledge of the biology of microsporidia is limited. Microsporidia were thought to lack mitochondria but the proposed host laboratory discovered, and have started to functionally characterise, highly reduced remnant mitochondria in these parasites, called mitosomes, which do not make ATP. Mitosomes are vital for parasite survival because they contain key components of the essential pathway for mitochondrial iron-sulphur cluster biosynthesis. However, from published and in- house genome data it appears that the transport proteins that support mitochondrial Fe-S protein biogenesis in model organisms, have been lost by the parasites. These data raise fundamental questions of how mitosomes function and import the substrates they need to produce Fe-S clusters or export the product(s) of this metabolism that (in model organisms) are needed for the biogenesis of essential cytosolic and nuclear Fe-S proteins. In the present proposal I will tackle these questions using a interdisciplinary program combining bioinformatics and organelle proteomics to identify putative mitosome proteins including transporters, molecular cell biology to functionally characterise these proteins, and detailed light and electron microscopy to confirm their localisation. The project will enhance my individual competence and potential for career development through experience of working in a leading UK laboratory with a track record of research training, international collaboration and scientific excellence."