Figure 3.2 Location of Toll like receptor:

 

Signaling pathway of TLR activation begins with the ligand binding either on the cell surface or in the endosome. The binding of ligand to TLR leads to dimerization of the TLR which further recruits the adaptor proteins such as MyD88. The adaptor proteins then activate the transcription factor such as NF-κβ, activation protein-1, interferon response factor-3 (IRF-3) and IRF-7. NF-κβ and activation protein-1stimulates the production of inflammatory cytokines (TNF and IL-1) while IRF-3 and -7 promote the production of type-I interferon.