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Kinase suppressor of Ras-1 protects against pulmonary Pseudomonas aeruginosa infections

Nature Medicine volume 17, pages 341346 (2011) | Download Citation


Pseudomonas aeruginosa is a Gram-negative pathogen that causes severe infections in immunocompromised individuals and individuals with cystic fibrosis or chronic obstructive pulmonary disease (COPD). Here we show that kinase suppressor of Ras-1 (Ksr1)-deficient mice are highly susceptible to pulmonary P. aeruginosa infection accompanied by uncontrolled pulmonary cytokine release, sepsis and death, whereas wild-type mice clear the infection. Ksr1 recruits and assembles inducible nitric oxide (NO) synthase (iNOS) and heat shock protein-90 (Hsp90) to enhance iNOS activity and to release NO upon infection. Ksr1 deficiency prevents lung alveolar macrophages and neutrophils from activating iNOS, producing NO and killing bacteria. Restoring NO production restores the bactericidal capability of Ksr1-deficient lung alveolar macrophages and neutrophils and rescues Ksr1-deficient mice from P. aeruginosa infection. Our findings suggest that Ksr1 functions as a previously unknown scaffold that enhances iNOS activity and is therefore crucial for the pulmonary response to P. aeruginosa infections.

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We thank R. Kolesnick (Memorial Sloan-Kettering Cancer Center) for providing us with Ksr1-deficient mice. This study was supported by Deutsche Forschungsgemeinschaft grants Gu 335/13-3 and Gu 335/16-2 to E.G.

Author information

Author notes

    • Yang Zhang
    •  & Xiang Li

    These authors contributed equally to this work.


  1. Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany.

    • Yang Zhang
    • , Xiang Li
    • , Alexander Carpinteiro
    • , Matthias Soddemann
    •  & Erich Gulbins
  2. Department of Cell and Developmental Biology, Vanderbilt University School of Medicine and Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee, USA.

    • Jeremy A Goettel


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Y.Z. performed the internalization assays, confocal and fluorescence microscopy, immunoprecipitation studies, flow cytometry analysis and protein overexpression and iNOS activity assays. X.L. conducted the mouse infection experiments, determined cytokine abundance in the lung and performed the bacterial-killing assay and immunoblot analysis. A.C. performed bone marrow transplantation and determined the neutrophil count. M.S. characterized the genotypes of Ksr1-deficient mice. J.A.G. cloned recombinant Ksr proteins. Y.Z., X.L. and E.G. designed the experiments and wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Erich Gulbins.

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