Myeloid differentiation primary response gene 88 （MYD88） is a cytosolic adapter protein， which has a central role in the innate and adaptive immune response. MYD88 functions as a vital signal transducer in the interleukin-1 and Toll-like receptor signaling pathways. MYD88 acts via IRAK1， IRAK2， IRF7 and TRAF6， leading to NF-kappa-B activation， cytokine secretion and the inflammatory response. The MYD88 protein increases IL-8 transcription. MYD88 is involved in IL-18-mediated signaling pathway. MYD88 activates IRF1， resulting in its rapid migration into the nucleus to mediate an efficient induction of IFN-beta， NOS2/INOS， and IL12A genes. MYD88 is comprised of an N-terminal death domain and a C-terminal Toll-interleukin1 receptor domain. Patients with defects in the MYD88 gene have an increased susceptibility to pyogenic bacterial infections.
