TLR 3
From Wikipedia, the free encyclopedia
• transmembrane receptor activity
• protein binding
• membrane
• hyperosmotic response
• signal transduction
• activation of NF-kappaB-inducing kinase
• detection of virus
• defense response to bacterium
• positive regulation of I-kappaB kinase/NF-kappaB cascade
• positive regulation of interferon-gamma biosynthetic process
• innate immune response
• positive regulation of interferon-alpha biosynthetic process
• positive regulation of interferon-beta biosynthetic process
• negative regulation of osteoclast differentiation
• positive regulation of JNK cascade
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 reoviruses. 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. TLR3 has also been designated as CD283 (cluster of differentiation 283).
[edit] 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 proposed 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.
