A Pseudomonas aeruginosa Type VI Secretion Phospholipase D Effector Targets Both Prokaryotic and Eukaryotic Cells

• Published in: Cell host & microbe 2014-05, Vol.15 (5), p.600-610
• Main Authors: Jiang, Feng, Waterfield, Nicholas R., Yang, Jian, Yang, Guowei, Jin, Qi
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacterial Secretion Systems; Host-Pathogen Interactions; Humans; Phosphatidylinositol 3-Kinases - genetics; Phosphatidylinositol 3-Kinases - metabolism; Phospholipase D - genetics; Phospholipase D - metabolism; Prokaryotic Cells - enzymology; Prokaryotic Cells - microbiology; Pseudomonas aeruginosa - enzymology; Pseudomonas aeruginosa - genetics; Pseudomonas Infections - enzymology; Pseudomonas Infections - genetics; Pseudomonas Infections - microbiology
• ISSN: 1931-3128; 1934-6069
• DOI: 10.1016/j.chom.2014.04.010

Widely found in animal and plant-associated proteobacteria, type VI secretion systems (T6SSs) are potentially capable of facilitating diverse interactions with eukaryotes and/or other bacteria. Pseudomonas aeruginosa encodes three distinct T6SS haemolysin coregulated protein (Hcp) secretion islands (H1, H2, and H3-T6SS), each involved in different aspects of the bacterium’s interaction with other organisms. Here we describe the characterization of a P. aeruginosa H3-T6SS-dependent phospholipase D effector, PldB, and its three tightly linked cognate immunity proteins. PldB targets the periplasm of prokaryotic cells and exerts an antibacterial activity. Surprisingly, PldB also facilitates intracellular invasion of host eukaryotic cells by activation of the PI3K/Akt pathway, revealing it to be a trans-kingdom effector. Our findings imply a potentially widespread T6SS-mediated mechanism, which deploys a single phospholipase effector to influence both prokaryotic cells and eukaryotic hosts. [Display omitted] •PldB is a H3-T6SS phospholipase D effector of P. aeruginosa•Three tightly linked cognate immunity proteins block PldB-induced bacterial toxicity•PldB is a trans-kingdom effector that targets both prokaryotic and eukaryotic cells•PldB facilitates host cell entry of P. aeruginosa by activating PI3K/Akt pathway Bacterial type VI secretion systems (T6SSs) can facilitate diverse interactions with eukaryotes and/or other bacteria. Jiang et al. characterize PldB as a T6SS phospholipase D effector of P. aeruginosa that targets the periplasm of bacteria lacking cognate immunity proteins and also facilitates host cell entry by mammalian PI3K/Akt pathway activation.