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ExoU is a potent intracellular phospholipase. Mol Microbiol 2004 Sep;53(5):1279-90



Pubmed ID




Scopus ID

2-s2.0-4444342607   197 Citations


The combination of a large genome encoding metabolic versatility and conserved secreted virulence determinants makes Pseudomonas aeruginosa a model pathogen that can be used to study host-parasite interactions in many eukaryotic hosts. One of the virulence regulons that likely plays a role in the ability of P. aeruginosa to avoid innate immune clearance in mammals is a type III secretion system (TTSS). Upon cellular contact, the P. aeruginosa TTSS is capable of delivering a combination of at least four different effector proteins, exoenzyme S (ExoS), ExoT, ExoU, and ExoY. Two of the four translocated proteins, ExoS and ExoU, are cytotoxic to cells during infection and transfection. The mechanism of cytotoxicity of ExoS is unclear. ExoU, however, has recently been characterized as a member of the phospholipase A family of enzymes, possessing at least phospholipase A2 activity. Similar to ExoS, ExoT and ExoY, ExoU requires either a eukaryotic-specific modification or cofactor for its activity in vitro. The biologic effects of minimal expression of ExoU in yeast can be visualized by membrane damage to different organelles and fragmentation of the vacuole. In mammalian cells, the direct injection of ExoU causes irreversible damage to cellular membranes and rapid necrotic death. ExoU likely represents a unique enzyme and is the first identified phopholipase virulence factor that is translocated into the cytosol by TTSS.

Author List

Sato H, Frank DW


Dara W. Frank PhD Professor in the Microbiology and Immunology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Bacterial Proteins
Bacterial Toxins
Carboxylic Ester Hydrolases
DNA-Binding Proteins
Enzyme Activation
Epithelial Cells
Genomic Islands
Molecular Sequence Data
Phospholipases A
Phospholipases A2
Plant Proteins
Pseudomonas aeruginosa
Sequence Alignment
Substrate Specificity
Virulence Factors
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a