Toll-like Receptors

Toll-like receptors (TLRs) are single transmembrane cell-surface receptors, which have a key role in the innate immune system. TLRs generally exist as homodimers (although TLR2-TLR6 heterodimers have been reported) and are found on immune cells such as macrophages, B lymphocytes and mast cells.

Toll-like receptors are activated by molecules associated with biological threat and are highly specific towards evolutionarily conserved entities on microbes, such as bacterial cell-surface lipopolysaccharides, flagella and unmethylated CpG islands. It has been suggested that some toll-like receptors may have endogenous ligands, such as Hsp60 and fibrinogen, and this has promoted speculation that endogenous toll-like receptor activators may have a pathological role in autoimmune disease.

Activation of toll-like receptors initiates downstream signaling cascades, initially via the adapter molecules MyD88, Trap, Trif and Tram, which converge on the PI3K and NF-κB pathways and regulate intracellular kinases and gene expression. This can stimulate an inflammatory and/or antigen-specific immune response. The signaling cascade coupled to toll-like receptor activation is very similar to that of interleukin-1 receptor (IL-1R) activation.

External sources of pharmacological information for Toll-like Receptors :

• BJP Guide

Pathways for Toll-like Receptors

Toll-like Receptor Signaling Pathway

TLR signaling is involved in the cellular response to threatening molecules such as bacteria and viruses. It results in an inflammatory and immmunological response.

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Toll-like Receptor Gene Data