The role of mitochondria in cellular defense against microbial infection. Mitochondria have been long recognized for their key role in the modulation of cell death pathways. Thus, it is therefore not surprising that this organelle represents a recurrent target for pathogenic microbes, aiming to manipulate the fate of the infected host cell. More recently, mitochondria have been shown to serve as a crucial platform for innate immune signaling, as illustrated by the identification of MAVS (also known as IPS-1, VISA and Cardif), NLRX1 and STING as mitochondrial proteins. This review discusses the tight interplay between microbial infection, innate immune signaling and mitochondria.