Interleukin-1 signaling, primarily via interleukin-1beta, plays important roles in innate and adaptive immune responses. Binding of the processed cytokine to its receptor allows for the recruitment of several accessory and adaptor proteins leading to the activation of NF-kappaB and MAPK signaling cascades. A natural receptor antagonist and a decoy receptor act as regulators of interleukin-1alpha and beta.