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Detection of True IgE-expressing Mouse B Lineage Cells
Published on: December 1, 2014
Cutting edge: Mouse NAIP1 detects the type III secretion system needle protein
Manira Rayamajhi1, Daniel E Zak, Joseph Chavarria-Smith
1Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
Journal of Immunology (Baltimore, Md. : 1950)
|September 18, 2013
Summary
Murine NAIP1 inflammasomes detect bacterial needle proteins, activating caspase-1. Priming or overexpression enhances NAIP1 sensitivity in macrophages, similar to human NAIP function.
Area of Science:
- Immunology
- Microbiology
Background:
- NAIP/NLRC4 inflammasomes activate caspase-1 in response to bacterial type III secretion systems (T3SSs).
- Murine NAIP2 and NAIP5/6 detect T3SS rod protein and flagellin, respectively.
Purpose of the Study:
- Identify the agonist for the orphan murine NAIP1 receptor.
- Characterize NAIP1 expression and function in macrophage responses to T3SS components.
Main Methods:
- Investigated NAIP1 activation by T3SS needle protein.
- Examined NAIP1 expression in bone marrow-derived macrophages (BMDMs) and peritoneal macrophages.
- Utilized polyinosinic-polycytidylic acid priming and retroviral transduction for NAIP1 overexpression in BMDMs.
Main Results:
- Identified the T3SS needle protein as the agonist for murine NAIP1.
- NAIP1 is poorly expressed in resting BMDMs but induced by priming.
- Overexpression or basal expression in peritoneal macrophages confers needle protein sensitivity.
Conclusions:
- Murine NAIP1 is the receptor for the T3SS needle protein.
- NAIP1 expression and function are regulated by priming and cell type.
- Murine NAIP1 is functionally analogous to human NAIP, which detects needle protein but not rod or flagellin.
