Interleukin-1 receptor-associated kinase 4 (IRAK4)

Serine/threonine-protein kinase that plays a critical role in initiating innate immune reaction against foreign pathogens. Is rapidly recruited by MYD88 into the receptor-signaling complex upon TLR activation to form the Myddosome together with IRAK2.

Phosphorylates originally IRAK1, thus stimulating the kinase activity and intensive autophosphorylation of IRAK1. Phosphorylates E3 ubiquitin ligases Pellino proteins (PELI1, PELI2 and PELI3) to promote pellino- mediated polyubiquitination of IRAK1.