The Legionella pneumophila effector LpdA is a palmitoylated phospholipase D virulence factor
File(s)
Accepted version
Supporting information
Author(s)
Type
Journal Article
Abstract
Legionella pneumophila is a bacterial pathogen that thrives in alveolar macrophages, causing a severe pneumonia. The virulence of L. pneumophila depends on its Dot/Icm type IV secretion system (T4SS), which delivers more than 300 effector proteins into the host, where they rewire cellular signaling to establish a replication-permissive niche, the Legionella-containing vacuole (LCV). Biogenesis of the LCV requires substantial redirection of vesicle trafficking and remodeling of intracellular membranes. In order to achieve this, several T4SS effectors target regulators of membrane trafficking, while others resemble lipases. Here, we characterized LpdA, a phospholipase D effector, which was previously proposed to modulate the lipid composition of the LCV. We found that ectopically expressed LpdA was targeted to the plasma membrane and Rab4- and Rab14-containing vesicles. Subcellular targeting of LpdA required a C-terminal motif, which is posttranslationally modified by S-palmitoylation. Substrate specificity assays showed that LpdA hydrolyzed phosphatidylinositol, -inositol-3- and -4-phosphate, and phosphatidylglycerol to phosphatidic acid (PA) in vitro. In HeLa cells, LpdA generated PA at vesicles and the plasma membrane. Imaging of different phosphatidylinositol phosphate (PIP) and organelle markers revealed that while LpdA did not impact on membrane association of various PIP probes, it triggered fragmentation of the Golgi apparatus. Importantly, although LpdA is translocated inefficiently into cultured cells, an L. pneumophila ΔlpdA mutant displayed reduced replication in murine lungs, suggesting that it is a virulence factor contributing to L. pneumophila infection in vivo.
Date Issued
2015-10-01
Date Acceptance
2015-07-18
Citation
Infection and Immunity, 2015, 83 (10), pp.3989-4002
ISSN
1098-5522
Publisher
American Society for Microbiology
Start Page
3989
End Page
4002
Journal / Book Title
Infection and Immunity
Volume
83
Issue
10
Copyright Statement
© 2015, American Society for Microbiology.
Sponsor
Medical Research Council (MRC)
Grant Number
MR/L018225/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Immunology
Infectious Diseases
PHOSPHATIDIC-ACID
PHOSPHATIDYLINOSITOL 3-PHOSPHATE
PHOSPHOINOSITIDE PHOSPHATASE
ENDOPLASMIC-RETICULUM
PROMOTES VIRULENCE
HOST
SECRETION
GOLGI
GENOME
CELLS
Animals
Bacterial Proteins
Cell Membrane
Humans
Legionella pneumophila
Legionnaires' Disease
Lipoylation
Mice
Phospholipase D
Protein Transport
Vacuoles
Virulence Factors
Microbiology
06 Biological Sciences
11 Medical And Health Sciences
07 Agricultural And Veterinary Sciences
Publication Status
Published