X

Forgot your Password

If you have forgotten your password, please enter your account email below and we will reset your password and email you the new password.

X

Login to SciCrunch

X

Register an Account

Delete Saved Search

Are you sure you want to delete this saved search?

NO

NIF LinkOut Portal

FILTERS

Cytosolic flagellin requires Ipaf for activation of caspase-1 and interleukin 1beta in salmonella-infected macrophages.

Authors:
Franchi L, Amer A, Body-Malapel M, Kanneganti TD, Ozören N, Jagirdar R, Inohara N, Vandenabeele P, Bertin J, Coyle A, Grant EP, Núñez G
Affiliation:
Journal:
Nature immunology

Abstract

Gram-negative bacteria that replicate in the cytosol of mammalian macrophages can activate a signaling pathway leading to caspase-1 cleavage and secretion of interleukin 1beta, a powerful host response factor. Ipaf, a cytosolic pattern-recognition receptor in the family of nucleotide-binding oligomerization domain-leucine-rich repeat proteins, is critical in such a response to salmonella infection, but the mechanism of how Ipaf is activated by the bacterium remains poorly understood. Here we demonstrate that salmonella strains either lacking flagellin or expressing mutant flagellin were deficient in activation of caspase-1 and in interleukin 1beta secretion, although transcription factor NF-kappaB-dependent production of interleukin 6 or the chemokine MCP-1 was unimpaired. Delivery of flagellin to the macrophage cytosol induced Ipaf-dependent activation of caspase-1 that was independent of Toll-like receptor 5, required for recognition of extracellular flagellin. In macrophages made tolerant by previous exposure to lipopolysaccharide, which abrogates activation of NF-kappaB and mitogen-activated protein kinases, salmonella infection still activated caspase-1. Thus, detection of flagellin through Ipaf induces caspase-1 activation independently of Toll-like receptor 5 in salmonella-infected and lipopolysaccharide-tolerized macrophages.

GO Links

  1. Welcome

    Welcome to NIF. Explore available research resources: data, tools and materials, from across the web

  2. Community Resources

    Search for resources specially selected for NIF community

  3. More Resources

    Search across hundreds of additional biomedical databases

  4. Literature

    Search Pub Med abstracts and full text from PubMed Central

  5. Insert your Query

    Enter your search terms here and hit return. Search results for the selected tab will be returned.

  6. Join the Community

    Click here to login or register and join this community.

  7. Categories

    Narrow your search by selecting a category. For additional help in searching, view our tutorials.

  8. Query Info

    Displays the total number of search results. Provides additional information on search terms, e.g., automated query expansions, and any included categories or facets. Expansions, filters and facets can be removed by clicking on the X. Clicking on the + restores them.

  9. Search Results

    Displays individual records and a brief description. Click on the icons below each record to explore additional display options.

X