When bacteria meet mitochondria: The strange case of the tick symbiont Midichloria mitochondrii †
Résumé
Mitochondria are key eukaryotic organelles, that perform several essential functions. Not surprisingly, different intracellular bacteria have been shown to directly or indirectly target mitochondria, to make the host cell a more hospitable niche for bacterial replication. The alphaproteobacterium Midichloria mitochondrii has taken this behavior to another level by physically colonizing mitochondria, as shown by transmission electron micrographs of bacteria residing in the mitochondrial intermembrane space. Such unique localization springs a number of questions, in terms of mechanisms allowing it and reasons driving it. We suggest possible scenarios that could lead to this peculiar localization and hypothesize potential benefits of mitochondrial colonization for the bacterium and its host.
