期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 283, 期 32, 页码 21881-21889出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M800672200
关键词
-
资金
- NIAID NIH HHS [R01 AI059372, AI59372, P01 AI044642] Funding Source: Medline
- PHS HHS [P0144642] Funding Source: Medline
Potent cell activation by endotoxin requires sequential protein-endotoxin and protein-protein interactions involving lipopolysaccharide-binding protein, CD14, MD-2, and Toll-like receptor 4 (TLR4). MD-2 plays an essential role by bridging endotoxin (E) recognition initiated by lipopolysaccharide-binding protein and CD14 to TLR4 activation by presenting endotoxin as a monomeric E .MD-2 complex that directly and potently activates TLR4. Secreted MD-2 (sMD-2) exists as a mixture of monomers and multimers. Published data suggest that only MD-2 monomer can interact with endotoxin and TLR4 and support cell activation, but the apparent instability of MD-2 has thwarted efforts to more fully separate and characterize the individual species of sMD-2. We have taken advantage of the much greater stability of sMD-2 in insect culture medium to fully separate sMD-2 monomer from dimer by gel sieving chromatography. At low nanomolar concentrations, the sMD-2 monomer, but not dimer, reacted with a monomeric complex of E . sCD14 to form monomeric E . MD-2 and activate HEK293/TLR4 cells. The monomer, but not dimer, also reacted with the ectodomain of TLR4 with an affinity comparable with the picomolar affinity of E . MD-2. These findings demonstrate directly that the monomeric form of sMD-2 is the active species both for reaction with E . CD14 and TLR4, as needed for potent endotoxin-induced TLR4 activation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据