The innate immune system performs the critical task of immediately protecting the host from infection and generating responses that alert and guide the actions of acquired immunity. Toll-like receptors (TLRs) are essential elements of innate immunity which upon direct recognition of microbial, fungal and viral components activate cellular events leading to inflammation, direct killing of the pathogen, and enhanced antigen presentation. Their essential role in inducing and regulating these events, is evidenced by their direct association with a variety of immune disorders ranging from sepsis, atherosclerosis, arthritis, asthma and autoimmunity. Among the ten member TLR family, TLR2 requires TLR1 or TLR6 to recognize, discriminate and initiate responses to a wide variety of rnicrobial components. Host responses are mediated by the two cytoplasmic proximal adaptor molecules known as MyD88 and TIRAP/MAL. The long term goal of this project is to define the mechanism by which this subfamily of TLRs recognize their agonists, initiate cellular responses, and coordinate these responses at the subcellular and molecular level.
The specific aims are 1) To define the precise role of TLRs 1 and 6 in recognition of microbial and fungal components as well as the extracellular regions of the receptors involved, 2) To determine the intracellular trafficking and physical interactions among TLRs 1, 2 and 6 and the proximal adaptor molecules MyD88 and TIRAP/ MAL upon agonist-mediated cell activation, and 3) To define the role of proximal signaling events; on the observed cell surface colocalization of TLRs and other TLR-associated endocytic trafficking events. The specific function of TLRs, with respect to agonist discrimination as well as the structural basis of this discrimination, are assessed through the use of synthetic; agonists and receptor domain swapping experiments. The localization of TLRs and adaptors are assessed through direct microscopy including FRET, membrane fractionation, and pharmacalogic agents. The effect of dominant negative molecules, shRNA and pharmacalogic agents address the role of signaling events on intracellular TLR trafficking.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI052344-04
Application #
7392393
Study Section
Special Emphasis Panel (ZRG1-III (01))
Program Officer
Palker, Thomas J
Project Start
2005-07-01
Project End
2010-03-31
Budget Start
2008-04-01
Budget End
2009-03-31
Support Year
4
Fiscal Year
2008
Total Cost
$275,598
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Physiology
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
Ranoa, Diana Rose E; Kelley, Stacy L; Tapping, Richard I (2013) Human lipopolysaccharide-binding protein (LBP) and CD14 independently deliver triacylated lipoproteins to Toll-like receptor 1 (TLR1) and TLR2 and enhance formation of the ternary signaling complex. J Biol Chem 288:9729-41
Kelley, Stacy L; Lukk, Tiit; Nair, Satish K et al. (2013) The crystal structure of human soluble CD14 reveals a bent solenoid with a hydrophobic amino-terminal pocket. J Immunol 190:1304-11
Hart, Bryan E; Tapping, Richard I (2012) Cell surface trafficking of TLR1 is differentially regulated by the chaperones PRAT4A and PRAT4B. J Biol Chem 287:16550-62
Hart, Bryan E; Tapping, Richard I (2012) Differential trafficking of TLR1 I602S underlies host protection against pathogenic mycobacteria. J Immunol 189:5347-55
Guan, Yue; Ranoa, Diana Rose E; Jiang, Song et al. (2010) Human TLRs 10 and 1 share common mechanisms of innate immune sensing but not signaling. J Immunol 184:5094-103
Guan, Yue; Omueti-Ayoade, Katherine; Mutha, Sarita K et al. (2010) Identification of novel synthetic toll-like receptor 2 agonists by high throughput screening. J Biol Chem 285:23755-62
Li, Xinyan; Jiang, Song; Tapping, Richard I (2010) Toll-like receptor signaling in cell proliferation and survival. Cytokine 49:1-9
Yun, Thomas H; Cott, Jessica E; Tapping, Richard I et al. (2009) Proteolytic inactivation of tissue factor pathway inhibitor by bacterial omptins. Blood 113:1139-48
Liang, Shuang; Hosur, Kavita B; Lu, Shanyun et al. (2009) Mapping of a microbial protein domain involved in binding and activation of the TLR2/TLR1 heterodimer. J Immunol 182:2978-85