The recently recognized family of patatin-like proteins is widely distributed among bacteria. They are defined by the presence of a patatin domain, which encodes phospholipase A2 activity. Although the vast majority of these proteins remain to be characterized, most of those examined to date are secreted by type III, type IV, or type V secretion systems, are translocated into host cells, and have attributes of virulence factors. Once in the intracellular environment, these phospholipases cause disruption of normal host cell physiology or cell death. The best characterized representative of the patatin-like family of proteins is ExoU of Pseudomonas aeruginosa. This protein, which is associated with virulence in both animal models and human infections, is secreted by the P. aeruginosa type III secretion pathway and causes rapid lysis of a broad spectrum of eukaryotic cells by a phospholipase A2 dependent mechanism. The overall goal of this application is to build upon prior work by our laboratory and others to further characterize the molecular mechanisms of ExoU and to extend these findings to other patatin-like proteins. We hypothesize that the membrane localization domain of ExoU targets this effector protein to the plasma membrane by binding phosphatidylinositol-4,5-bisphosphate and that this binding markedly enhances ExoU phospholipase A2 activity. We hypothesize that ExoU undergoes multimerization once at the plasma membrane. Finally, we suggest a therapeutic strategy whereby the cytotoxic activity of ExoU can be exploited to eradicate P. aeruginosa and other bacteria that target lytic toxins to neutrophils. In this application, we propose aims to test each of these hypotheses. The completion of these aims will further define the molecular mechanisms of patatin-like proteins and lay the foundation for the development of novel therapeutic interventions for patients infected by bacteria that lyse neutrophils.

Public Health Relevance

Our goal is to understand how a prevalent family of bacterial proteins called patatin-like proteins contributes to infections. Our focus is on ExoU, a toxin made by the bacterium Pseudomonas aeruginosa, one of the most frequent causes of pneumonia acquired in the hospital. Our overall objective has been to understand how this toxin contributes to the ability of P. aeruginosa to cause severe infections. This information will lay te foundation for therapeutic interventions useful in the treatment of these infections.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Special Emphasis Panel (ZRG1-IDM-S (02))
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Korpela, Jukka K
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Northwestern University at Chicago
Schools of Medicine
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Zhang, Angelica; Veesenmeyer, Jeffrey L; Hauser, Alan R (2018) Phosphatidylinositol 4,5-Bisphosphate-Dependent Oligomerization of the Pseudomonas aeruginosa Cytotoxin ExoU. Infect Immun 86:
Hughes, A J; Knoten, C A; Morris, A R et al. (2018) ASC acts in a caspase-1-independent manner to worsen acute pneumonia caused by Pseudomonas aeruginosa. J Med Microbiol 67:1168-1180
Rutherford, Victoria; Yom, Kelly; Ozer, Egon A et al. (2018) Environmental reservoirs for exoS+ and exoU+ strains of Pseudomonas aeruginosa. Environ Microbiol Rep 10:485-492
Prickett, Michelle H; Hauser, Alan R; McColley, Susanna A et al. (2017) Aminoglycoside resistance of Pseudomonas aeruginosa in cystic fibrosis results from convergent evolution in the mexZ gene. Thorax 72:40-47
Krapp, Fiorella; Morris, Andrew R; Ozer, Egon A et al. (2017) Virulence Characteristics of Carbapenem-Resistant Klebsiella pneumoniae Strains from Patients with Necrotizing Skin and Soft Tissue Infections. Sci Rep 7:13533
Berube, Bryan J; Murphy, Katherine R; Torhan, Matthew C et al. (2017) Impact of Type III Secretion Effectors and of Phenoxyacetamide Inhibitors of Type III Secretion on Abscess Formation in a Mouse Model of Pseudomonas aeruginosa Infection. Antimicrob Agents Chemother 61:
Hauser, Alan R; Mecsas, Joan; Moir, Donald T (2016) Beyond Antibiotics: New Therapeutic Approaches for Bacterial Infections. Clin Infect Dis 63:89-95
Fitzpatrick, Margaret A; Ozer, Egon A; Hauser, Alan R (2016) Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks. J Clin Microbiol 54:593-612
Berube, Bryan J; Rangel, Stephanie M; Hauser, Alan R (2016) Pseudomonas aeruginosa: breaking down barriers. Curr Genet 62:109-13
Ozer, Egon A; Morris, Andrew R; Krapp, Fiorella et al. (2016) Draft Genome Sequence of a Multidrug-Resistant Klebsiella quasipneumoniae subsp. similipneumoniae Isolate from a Clinical Source. Genome Announc 4:

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