MyD88 adaptor protein is used by
Most Toll-like receptors signal through the adaptor MyD88, which recruits IRAK kinases and ultimately activates NF-κB and MAP kinases. TLR3 and the endosomal form of TLR4 instead use the adaptor TRIF to activate IRF3 and type-I interferon production. The choice of adaptor therefore determines the balance between inflammatory and antiviral transcriptional programs.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)