Document Detail


Inhibition of pathogen-induced apoptosis by a Coxiella burnetii type IV effector protein.
MedLine Citation:
PMID:  20944063     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Coxiella burnetii and Legionella pneumophila are evolutionarily related pathogens with different intracellular infection strategies. C. burnetii persists within and is transmitted by mammalian hosts, whereas, L. pneumophila is found primarily in the environment associated with protozoan hosts. Although a type IV secretion system encoded by the defect in organelle trafficking (dot) and intracellular multiplication (icm) genes is a virulence determinant that remains highly conserved in both bacteria, the two pathogens encode a different array of effector proteins that are delivered into host cells by the Dot/Icm machinery. This difference suggests that adaptations to evolutionarily distinct hosts may be reflected in the effector protein repertoires displayed by these two pathogens. Here we provide evidence in support of this hypothesis. We show that a unique C. burnetii effector from the ankyrin repeat (Ank) family called AnkG interferes with the mammalian apoptosis pathway. AnkG was found to interact with the host protein gC1qR (p32). Either the addition of AnkG to the repertoire of L. pneumophila effector proteins or the silencing of p32 in mouse dendritic cells resulted in a gain of function that allowed intracellular replication of L. pneumophila in these normally restrictive mammalian host cells by preventing rapid pathogen-induced apoptosis. These data indicate that p32 regulates pathogen-induced apoptosis and that AnkG functions to block this pathway. Thus, emergence of an effector protein that interferes with a proapoptotic signaling pathway directed against intracellular bacteria correlates with adaptation of a pathogen to mammalian hosts.
Authors:
Anja Lührmann; Catarina V Nogueira; Kimberly L Carey; Craig R Roy
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-10-13
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  107     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-03     Completed Date:  2010-11-30     Revised Date:  2011-11-03    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  18997-9001     Citation Subset:  IM    
Affiliation:
Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Motifs
Animals
Antigens, CD44 / genetics,  immunology*,  metabolism
Apoptosis / genetics,  immunology*
Bacterial Proteins / genetics,  immunology*,  metabolism
Coxiella burnetii / pathogenicity,  physiology*
Dendritic Cells / immunology,  microbiology
HEK293 Cells
Host-Pathogen Interactions / immunology*
Humans
Legionella pneumophila / pathogenicity,  physiology*
Mice
Q Fever / genetics,  immunology*,  metabolism
Grant Support
ID/Acronym/Agency:
AI066547/AI/NIAID NIH HHS; R01 AI048770-12/AI/NIAID NIH HHS; R01 AI064559-05/AI/NIAID NIH HHS; R01-AI048770/AI/NIAID NIH HHS; R01-AI064559/AI/NIAID NIH HHS; U54-AI057158-LIPKIN/AI/NIAID NIH HHS
Chemical
Reg. No./Substance:
0/Antigens, CD44; 0/Bacterial Proteins; 0/C1qbp protein, mouse
Comments/Corrections

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