TLR 3

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Toll-like receptor 3
250px
The structure of TLR3 covered with sugars
Available structures
PDB Ortholog search: Template:Homologene2PDBe PDBe, Template:Homologene2uniprot RCSB
Identifiers
Symbols TLR3 ; CD283
External IDs Template:OMIM5 Template:MGI HomoloGene20696
RNA expression pattern
File:PBB GE TLR3 206271 at tn.png
More reference expression data
Orthologs
Template:GNF Ortholog box
Species Human Mouse
Entrez n/a n/a
Ensembl n/a n/a
UniProt n/a n/a
RefSeq (mRNA) n/a n/a
RefSeq (protein) n/a n/a
Location (UCSC) n/a n/a
PubMed search n/a n/a

TLR 3 is a member of the Toll-like receptor family of pattern recognition receptors of the innate immune system. Discovered in 2001,[1] TLR3 recognizes double-stranded RNA, a form of genetic information carried by some viruses such as influenza. Upon recognition, TLR 3 induces the activation of NF-kB to increase production of type I interferons which signal other cells to increase their antiviral defenses. Double-stranded RNA is also recognised by the cytoplasmic receptors RIG-I and MDA-5.

Structure

The structure of TLR3 was reported in June 2005 by researchers at The Scripps Research Institute.[2] TLR3 forms a large horseshoe shape that contacts with a neighboring horseshoe, forming a "dimer" of two horseshoes. Much of the TLR3 protein surface is covered with sugar molecules, making it a glycoprotein, but on one face (including the interface between the two horseshoes), there is a large sugar-free surface. This surface also contains two distinct patches rich in positively-charged amino acids, which may be a binding site for negatively-charged double-stranded RNA.

Despite being a glycoprotein, TLR3 crystallises readily - a prerequisite for structural analysis by x-ray crystallography.

References

  1. Alexopoulou L, Holt A, Medzhitov R, Flavell R (2001). "Recognition of double-stranded RNA and activation of NF-kappaB by Toll-like receptor 3". Nature. 413 (6857): 732–8. PMID 11607032.
  2. Choe J, Kelker M, Wilson I (2005). "Crystal structure of human toll-like receptor 3 (TLR3) ectodomain". Science. 309 (5734): 581–5. PMID 15961631.

Further reading

  • Lien E, Ingalls RR (2002). "Toll-like receptors". Crit. Care Med. 30 (1 Suppl): S1–11. PMID 11782555.

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