Toll-like receptor 4 (TLR4)

Toll-like receptor 4 (TLR4), also known as CD284, is an essential pattern recognition receptor (PRR) that detects both microbial invaders via PAMPs—especially bacterial LPS—and endogenous danger signals via DAMPs. Its activation triggers complex signaling cascades leading to inflammation necessary for pathogen clearance but potentially harmful if uncontrolled. It is a transmembrane protein of approximately 95 kDa encoded by the TLR4 gene and belongs to the toll-like receptor family. TLR4 plays a central role in detecting microbial components, especially lipopolysaccharides (LPS) from Gram-negative bacteria, initiating rapid activation of innate immunity. It also recognizes endogenous DAMPs released during tissue injury or cell death, such as HMGB1 and S100 proteins. Activation of TLR4 leads to proinflammatory responses that are crucial for fighting infections but can also contribute to acute and chronic inflammatory diseases if dysregulated.

Other names

CD284

Modulation of TLR4 signaling pathways (MyD88-dependent and TRIF-dependent), typically aimed at inhibiting downstream inflammatory cytokine production.