Expression of functional D299G.T399I polymorphic variant of TLR4 depends more on coexpression of MD-2 than does wild-type TLR4.
J Immunol
; 184(8): 4362-7, 2010 Apr 15.
Article
in En
| MEDLINE
| ID: mdl-20212095
ABSTRACT
Two missense variants (D299G and T399I) of TLR4 are cosegregated in individuals of European descent and, in a number of test systems, result in reduced responsiveness to endotoxin. How these changes within the ectodomain (ecd) of TLR4 affect TLR4 function is unclear. For both wild-type and D299G.T399I TLR4, we used endotoxinCD14 and endotoxinMD-2 complexes of high specific radioactivity to measure:
1) interaction of recombinant MD-2TLR4 with endotoxinCD14 and TLR4 with endotoxinMD-2; 2) expression of functional MD-2TLR4 and TLR4; and 3) MD-2TLR4 and TLR4-dependent cellular endotoxin responsiveness. Both wild-type and D299G.T399I TLR4(ecd) demonstrated high affinity (K(d) approximately 200 pM) interaction of endotoxinCD14 with MD-2TLR4(ecd) and endotoxinMD-2 with TLR4(ecd). However, levels of functional TLR4 were reduced up to 2-fold when D299G.T399I TLR4 was coexpressed with MD-2 and >10-fold when expressed without MD-2, paralleling differences in cellular endotoxin responsiveness. The dramatic effect of the D299G.T399I haplotype on expression of functional TLR4 without MD-2 suggests that cells expressing TLR4 without MD-2 are most affected by these polymorphisms.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Polymorphism, Genetic
/
Genetic Variation
/
Mutation, Missense
/
Lymphocyte Antigen 96
/
Toll-Like Receptor 4
Limits:
Humans
Language:
En
Journal:
J Immunol
Year:
2010
Document type:
Article
Affiliation country: