ATG12 and staphylococcus aureus infection: On the other hand, the invasion assays performed with Atg5 knock-down cells showed that Atg5, component of the Atg12-Atg5-Atg16 complex which acts as a ligase for LC3-phosphatidylethanolamine conjugation, is essential for the autophagy activated by Serratia. Mestre et al[33] recently demonstrated that, in the Staphylococcus aureus infection, α-toxin-dependent activation of autophagy is independent of PI3K activity.