Journal article
A Functional Core of IncA Is Required for Chlamydia trachomatis Inclusion Fusion
Journal of bacteriology, Vol.198(8), pp.1347-1355
04/2016
DOI: 10.1128/JB.00933-15
PMCID: PMC4859576
PMID: 26883826
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that is the etiological agent of a variety of human diseases, including blinding trachoma and sexually transmitted infections. Chlamydiae replicate within a membrane-bound compartment, termed an inclusion, which they extensively modify by the insertion of type III secreted proteins called Inc proteins. IncA is an inclusion membrane protein that encodes two coiled-coil domains that are homologous to eukaryotic SNARE (soluble N-ethylmaleimide-sensitive factor attachment receptor) motifs. Recent biochemical evidence suggests that a functional core, composed of SNARE-like domain 1 (SLD-1) and part of SNARE-like domain 2 (SLD-2), is required for the characteristic homotypic fusion of C. trachomatis inclusions in multiply infected cells. To verify the importance of IncA in homotypic fusion in Chlamydia, we generated an incA::bla mutant. Insertional inactivation of incA resulted in the formation of nonfusogenic inclusions, a phenotype that was completely rescued by complementation with full-length IncA. Rescue of homotypic inclusion fusion was dependent on the presence of the functional core consisting of SLD-1 and part of SLD-2. Collectively, these results confirm in vitro membrane fusion assays identifying functional domains of IncA and expand the genetic tools available for identification of chlamydia with a method for complementation of site-specific mutants.
Chlamydia trachomatis replicates within a parasitophorous vacuole termed an inclusion. The chlamydial inclusions are nonfusogenic with vesicles in the endocytic pathway but, in multiply infected cells, fuse with each other to form a single large inclusion. This homotypic fusion is dependent upon the presence of a chlamydial inclusion membrane-localized protein, IncA. Specificity of membrane fusion in eukaryotic cells is regulated by SNARE (soluble N-ethylmaleimide sensitive factor attachment receptor) proteins on the cytosolic face of vesicles and target membranes. IncA contains two SNARE-like domains. Newly developed genetic tools for the complementation of targeted mutants in C. trachomatis are used to confirm the minimal requirement of SNARE-like motifs necessary to promote the homotypic fusion of inclusions.
Details
- Title: Subtitle
- A Functional Core of IncA Is Required for Chlamydia trachomatis Inclusion Fusion
- Creators
- Mary M Weber - Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USANicholas F Noriea - Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USALaura D Bauler - Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USAJennifer L Lam - Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USAJanet Sager - Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USAJordan Wesolowski - Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, USAFabienne Paumet - Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, USATed Hackstadt - Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA ted_hackstadt@nih.gov
- Resource Type
- Journal article
- Publication Details
- Journal of bacteriology, Vol.198(8), pp.1347-1355
- DOI
- 10.1128/JB.00933-15
- PMID
- 26883826
- PMCID
- PMC4859576
- ISSN
- 0021-9193
- eISSN
- 1098-5530
- Grant note
- AI000567 / NIAID NIH HHS AI116983 / NIAID NIH HHS R01 AI073486 / NIAID NIH HHS R01 AI116983 / NIAID NIH HHS AI073486 / NIAID NIH HHS R56 AI073486 / NIAID NIH HHS
- Language
- English
- Date published
- 04/2016
- Academic Unit
- Molecular Physiology and Biophysics; Microbiology and Immunology
- Record Identifier
- 9984083291502771
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