Figure 1

Recognition of an appropriate ligand (for example, lipopolysaccharide) triggers the Toll-like receptor to recruit MyD88. MyD88 interacts with the Toll-like receptor through its own Toll/IL-1 receptor domain and in turn engages the serine-threonine kinase IRAK though a death domain. Signal transduction factors such as TRAF6 carry the signal through a series of phosphorylations until NFκB is ultimately released to the nucleus where it can activate the transcription of appropriate immune response genes.