IRAK

Interleukin-1 receptor-associated kinases (IRAKs), are serine/threonine kinases, play critical roles in initiating innate immune responses against foreign pathogens and other types of dangers through their role in Toll-like receptor (TLR) and interleukin 1 receptor (IL-1R) mediated signaling pathways. The four different IRAK-like molecules have been identified: two active kinases, IRAK-1 and IRAK-4, and two inactive kinases, IRAK-2 and IRAK-M. All IRAKs mediate activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways.

Toll-like receptors transduce their signals through the adaptor molecule MyD88 and members of the IL-1R-associated kinase family (IRAK-1, 2, M and 4). IRAK-1 and IRAK-2, known to form Myddosomes with MyD88-IRAK-4, mediate TLR7-induced TAK1-dependent NF-κB activation. IRAK-M is known to function as a negative regulator that prevents the dissociation of IRAKs from MyD88, thereby inhibiting downstream signalling.