Abstract
A cell surface heterodimer Toll-like receptor 4 (TLR4)/MD-2 senses lipopolysaccharide (LPS), a principal membrane component of Gram-negative bacteria. LPS binds to MD-2 and induces dimerization of TLR4/MD-2. Dimerized TLR4 activates downstream signaling. TLR4 polymorphism replacing Asp299 with Gly and Thr399 with Ile (D299G/T399I) causes LPS hyporesponsiveness, and is associated with a variety of infectious and noninfectious diseases. However, a molecular mechanism underlying the LPS hyporesponsiveness remains controversial. We here asked whether the TLR4 polymorphism influenced cell surface expression of TLR4/MD-2, ligand-dependent TLR4/MD-2 dimerization or TLR4/ MD-2 responses to a weak agonist monophosphoryl lipid A (MPL). A newly established anti-TLR4 mAb detected D299G/T399I TLR4/MD-2 on Ba/F3 cells whereas a previous anti-TLR4 mAb did not, suggesting that the D299G/T399I polymorphism caused a conformational change in TLR4. Hyporesponsiveness of D299G/T399I TLR4/MD-2 was much more apparent when cells were stimulated with MPL than with lipid A. MPL-dependent TLR4/MD-2 dimerization was impaired by the D299G/T399I polymorphism. The D299G/T399I polymorphism did not alter LPS-binding to soluble TLR4/MD-2, but impaired its dimerization. These results suggest that the D299G/T399I TLR4 polymorphism impairs TLR4/MD-2 responses by altering ligand-dependent dimerization.
| Original language | English |
|---|---|
| Pages (from-to) | 45-52 |
| Number of pages | 8 |
| Journal | International Immunology |
| Volume | 25 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 1 2013 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Immunology
Cite this
Human TLR4 polymorphism D299G/T399I alters TLR4/MD-2 conformation and response to a weak ligand monophosphoryl lipid A. / Yamakawa, Natsuko; Ohto, Umeharu; Akashi-Takamura, Sachiko; Takahashi, Koichiro; Saitoh, Shin Ichiroh; Tanimura, Natsuko; Suganami, Takayoshi; Ogawa, Yoshihiro; Shibata, Takuma; Shimizu, Toshiyuki; Miyake, Kensuke.
In: International Immunology, Vol. 25, No. 1, 01.01.2013, p. 45-52.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Human TLR4 polymorphism D299G/T399I alters TLR4/MD-2 conformation and response to a weak ligand monophosphoryl lipid A
AU - Yamakawa, Natsuko
AU - Ohto, Umeharu
AU - Akashi-Takamura, Sachiko
AU - Takahashi, Koichiro
AU - Saitoh, Shin Ichiroh
AU - Tanimura, Natsuko
AU - Suganami, Takayoshi
AU - Ogawa, Yoshihiro
AU - Shibata, Takuma
AU - Shimizu, Toshiyuki
AU - Miyake, Kensuke
PY - 2013/1/1
Y1 - 2013/1/1
N2 - A cell surface heterodimer Toll-like receptor 4 (TLR4)/MD-2 senses lipopolysaccharide (LPS), a principal membrane component of Gram-negative bacteria. LPS binds to MD-2 and induces dimerization of TLR4/MD-2. Dimerized TLR4 activates downstream signaling. TLR4 polymorphism replacing Asp299 with Gly and Thr399 with Ile (D299G/T399I) causes LPS hyporesponsiveness, and is associated with a variety of infectious and noninfectious diseases. However, a molecular mechanism underlying the LPS hyporesponsiveness remains controversial. We here asked whether the TLR4 polymorphism influenced cell surface expression of TLR4/MD-2, ligand-dependent TLR4/MD-2 dimerization or TLR4/ MD-2 responses to a weak agonist monophosphoryl lipid A (MPL). A newly established anti-TLR4 mAb detected D299G/T399I TLR4/MD-2 on Ba/F3 cells whereas a previous anti-TLR4 mAb did not, suggesting that the D299G/T399I polymorphism caused a conformational change in TLR4. Hyporesponsiveness of D299G/T399I TLR4/MD-2 was much more apparent when cells were stimulated with MPL than with lipid A. MPL-dependent TLR4/MD-2 dimerization was impaired by the D299G/T399I polymorphism. The D299G/T399I polymorphism did not alter LPS-binding to soluble TLR4/MD-2, but impaired its dimerization. These results suggest that the D299G/T399I TLR4 polymorphism impairs TLR4/MD-2 responses by altering ligand-dependent dimerization.
AB - A cell surface heterodimer Toll-like receptor 4 (TLR4)/MD-2 senses lipopolysaccharide (LPS), a principal membrane component of Gram-negative bacteria. LPS binds to MD-2 and induces dimerization of TLR4/MD-2. Dimerized TLR4 activates downstream signaling. TLR4 polymorphism replacing Asp299 with Gly and Thr399 with Ile (D299G/T399I) causes LPS hyporesponsiveness, and is associated with a variety of infectious and noninfectious diseases. However, a molecular mechanism underlying the LPS hyporesponsiveness remains controversial. We here asked whether the TLR4 polymorphism influenced cell surface expression of TLR4/MD-2, ligand-dependent TLR4/MD-2 dimerization or TLR4/ MD-2 responses to a weak agonist monophosphoryl lipid A (MPL). A newly established anti-TLR4 mAb detected D299G/T399I TLR4/MD-2 on Ba/F3 cells whereas a previous anti-TLR4 mAb did not, suggesting that the D299G/T399I polymorphism caused a conformational change in TLR4. Hyporesponsiveness of D299G/T399I TLR4/MD-2 was much more apparent when cells were stimulated with MPL than with lipid A. MPL-dependent TLR4/MD-2 dimerization was impaired by the D299G/T399I polymorphism. The D299G/T399I polymorphism did not alter LPS-binding to soluble TLR4/MD-2, but impaired its dimerization. These results suggest that the D299G/T399I TLR4 polymorphism impairs TLR4/MD-2 responses by altering ligand-dependent dimerization.
UR - http://www.scopus.com/inward/record.url?scp=84872149610&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84872149610&partnerID=8YFLogxK
U2 - 10.1093/intimm/dxs084
DO - 10.1093/intimm/dxs084
M3 - Article
C2 - 22962435
AN - SCOPUS:84872149610
VL - 25
SP - 45
EP - 52
JO - International Immunology
JF - International Immunology
SN - 0953-8178
IS - 1
ER -