Human IRAK1 Synthetic Peptide. Interleukin-1 receptor-associated kinase 1 (IRAK1) is a serine/threonine-protein kinase that plays a critical role in initiating innate immune response against foreign pathogens. IRAK is associated with Toll-like receptor (TLR) and IL-1R signaling pathways. It is rapidly recruited by MYD88 to the receptor-signaling complex upon TLR activation. IRAK's association with MYD88 leads to IRAK1 phosphorylation by IRAK4 and subsequent autophosphorylation and kinase activation. Alternatively, IRAK1 can phosphorylate TIRAP to promote its ubiquitination and subsequent degradation. IRAK1 also phosphorylates the interferon regulatory factor 7 (IRF7) to induce its activation and translocation to the nucleus. This results in