Images

Figure from Pizarro-Cerda J, Cossart P. J Pathol. 2006 Jan;208(2):215-23.

Figure 4. Listeriolysin O (LLO) activity during bacterial entry. Active LLO is secreted during the invasion phase and potentiates the entry of L. monocytogenes. Once the bacteria are within a phagosome, the LLO becomes more active because it is adapted to the acidic pH of the intra-phagosomal environment, favouring the lysis of this compartment. Once the phagosome is broken, the bacteria are freed into the cytoplasm where the LLO is neutralized by the neutral pH of the cytosol; the host cell also recognizes a PEST sequence in the LLO, targeting this molecule to the cell degradation machinery.