title: Protease IV, a quorum sensing-dependent protease of Pseudomonas aeruginosa modulates insect innate immunity.
abstract: In Pseudomonas aeruginosa, quorum sensing (QS) plays an essential role in pathogenesis and the QS response controls many virulence factors. Using a mealworm, Tenebrio molitor as a host model, we found that Protease IV, a QS-regulated exoprotease of P. aeruginosa functions as a key virulence effector causing the melanization and death of T. molitor larvae. Protease IV was able to degrade zymogens of spätzle processing enzyme (SPE) and SPE-activating enzyme (SAE) without the activation of the antimicrobial peptide (AMP) production. Since SPE and SAE function to activate spätzle, a ligand of Toll receptor in the innate immune system of T. molitor, we suggest that Protease IV may interfere with the activation of the Toll signaling. Independently of the Toll pathway, the melanization response, another innate immunity was still generated, since Protease IV directly converted Tenebrio prophenoloxidase into active phenoloxidase. Protease IV also worked as an important factor in the virulence to brine shrimp and nematode. These results suggest that Protease IV provides P. aeruginosa with a sophisticated way to escape the immune attack of host by interfering with the production of AMPs.
authors.affiliation: College of Pharmacy, Pusan National University, Pusan, 609-735, Korea.
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Soo-Kyoung
authors.initials: SK
authors.lastname: Kim
authors.forename: Yong-In
authors.initials: YI
authors.lastname: So
authors.forename: Ha-Young
authors.initials: HY
authors.lastname: Park
authors.forename: Xi-Hui
authors.initials: XH
authors.lastname: Li
authors.forename: Doo Hwan
authors.initials: DH
authors.lastname: Yeom
authors.forename: Mi-Nan
authors.initials: MN
authors.lastname: Lee
authors.forename: Bok-Luel
authors.initials: BL
authors.lastname: Lee
authors.forename: Joon-Hee
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D004792:Enzyme Precursors; D007113:Immunity, Innate; D019476:Insect Proteins / Q000378:metabolism; D008543:Melanins / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D053038:Quorum Sensing; D013712:Tenebrio / Q000196:embryology / Q000276:immunology* / Q000382:microbiology; D051193:Toll-Like Receptors / Q000378:metabolism; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004792:Enzyme Precursors; D019476:Insect Proteins; D008543:Melanins; D051193:Toll-Like Receptors; D037521:Virulence Factors; D010447:Peptide Hydrolases; C030732:protease IV