Toll-Like Receptor (TLR) Signaling

Pattern recognition receptors activating innate immune responses.

Overview

Toll-like receptors (TLRs) detect conserved molecular patterns on pathogens (PAMPs) and damage-associated molecular patterns (DAMPs). Upon ligand binding, TLRs recruit adapter proteins (MyD88, TRIF) to activate NF-κB, MAPKs, and IRFs, leading to production of inflammatory cytokines and type I interferons.

Cellular Location

Cell surface and endosomes

Clinical Significance

First line of immune defense; TLR agonists used as vaccine adjuvants; dysregulation contributes to sepsis and autoimmune diseases.

Key Molecules

TLR1-10 LPS CpG DNA dsRNA MyD88 TRIF TRAM TIRAP Type I IFNs

Key Enzymes

IRAK1/4 TRAF6 TAK1 TBK1 IRF3/7

Related Pathways

NF-κB Pathway

Master regulator of inflammation, immunity, and cell survival.

JAK-STAT Pathway

Cytokine-driven signaling from receptor to gene expression via STAT dimerization.

Inflammasome Pathway

Intracellular sensor complexes activating inflammatory caspases and IL-1β/IL-18.