Toll-like Receptor Signaling Pathway

1. Toll-like Receptor Signaling Pathway What is Toll-like receptor? Toll-like receptors (TLRs) are a class of proteins that play a key role in innate immunity. They are single domain trans-membrane receptors belong to pattern recognition receptors (PRRs) which usually expressed in sentinel cells such as macrophages dendritic cells and many other non-immune cells such as fibroblasts and epithelial cells. They recognize structurally conserved molecules derived from microbes which are called pathogen-associated molecular patterns (PAMPs) or self-derived molecules derived from damaged cells, referred as damage associated molecules patterns (DAMPs). PAMPs include various bacterial lipopolysaccharide (LPS), peptidoglycan (PGN) and lipopeptides, as well as flagellin, bacterial DNA and viral double-stranded RNA. DAMPs include intracellular proteins such as heat shock proteins as well as protein fragments from the extracellular matrix. PRRs activate downstream signaling pathways that lead to the induction of innate immune responses by producing inflammatory cytokines, type I interferon (IFN), and other mediators. These processes not only trigger immediate host defensive responses such as inflammation, but also prime and orchestrate antigen-specific adaptive immune responses. These responses are essential for the clearance of infecting microbes as well as crucial for the consequent instruction of antigen-specific adaptive immune responses. cell wall components such as http://www.creative-diagnostics.com/Toll-like-Receptor-Signaling-Pathway.htm