Figure 6.
QS-mediated post-secretional activation of PIV. The initial expression of both PIV and LasB is positively regulated by QS. The prepro-PIV in cytoplasm is processed twice from N-terminus during secretion to release signal peptide, propeptide, and mature PIV in extracellular space. The mature PIV is inhibited by the propeptide binding. The mature LasB then degrades the propeptide to release activate PIV. LasB is also processed in a similar manner and inhibited by its propeptide (PPLasB). The processing of pro-LasB to mature LasB is achieved by auto-cleavage. SP, signal peptide; PP, propeptide.