Pseudomonas aeruginosa and its arsenal of proteases: Weapons to battle the host

Pseudomonas aeruginosa is a ubiquitous and opportunistic human pathogen thatrepresents a critical problem to the clinician due to the increased number ofresistant strains isolated from hospital settings. In addition, there is a greatvariety of pathologies associated with this versatile Gram-negative bacterium. P. aeruginosa cells are able to produce an incredible arsenal of virulence factors, especially secreted molecules that act singly or together to ensure theestablishment, maintenance, and persistence of a successful infection insusceptible hosts. In this context, pseudomonal proteases' roles are highlighteddue to their ability to cleave key host proteinaceous substrates as well as tomodulate several biological processes, for example, escaping and modulating thehost immune responses in the bacterial own favor. Proteases secreted byP. aeruginosa include elastase A (LasA), elastase B (LasB), alkaline protease(AP), protease IV (PIV), Pseudomonas small protease (PASP), large protease A(LepA), MucD, and P. aeruginosa aminopeptidase (PAAP). In the presentreview, we discuss the role of each of these relevant proteases produced by P. aeruginosa taking into consideration their main biological functions in thebacterium-host interaction that favors the establishment of the infectiousprocess.