Function: Adapter protein involved in the Toll-like receptor and IL-1 receptor signaling pathway in the innate immune response. Acts via IRAK1, IRAK2, IRF7 and TRAF6, leading to NF-kappa-B activation, cytokine secretion and the inflammatory response. Increases IL-8 transcription. Involved in IL-18-mediated signaling pathway. Tissue specificity: Ubiquitous. Disease: Defects in MYD88 are the cause of MYD88 deficiency (MYD88D) [MIM:612260]; also known as recurrent pyogenic bacterial infections due to MYD88 deficiency. Patients suffer from autosomal recessive, life-threatening, often recurrent pyogenic bacterial infections, including invasive pneumococcal disease, and die between 1 and 11 months of age. Surviving patients are otherwise healthy, with normal resistance to other microbes, and their clinical status improved with age. Similarity: Contains 1 death domain. Contains 1 TIR domain. Domain: The intermediate domain (ID) is required for the phosphorylation and activation of IRAK.