Autophagy and toxins: a matter of life or death.

Bacterial protein toxins are important virulence factors. A particular class of toxins, the pore-form toxins (PFTs), shares the toxigenic mechanism of forming pores in the membrane of target cells. The relationship between autophagy and bacterial PFTs has been described for several toxin-secreting pathogens and in this review we have recapitulated the more recent findings on this issue. A common outcome is that the target cell, by a yet non-completely defined mechanism, senses the toxin attack and builds up complex responses as a protective mechanism for host survival. However, in some cases, this cellular response is beneficial to the microorganism by supplying an intracellular niche or by promoting host-cell death, which facilitates pathogen spreading.