A chimeric type II/type I interleukin-1 receptor can mediate interleukin-1 induction of gene expression in T cells. 
The type I interleukin-1 receptor (IL-1R) is capable of transducing a signal resulting in promoter activation in T cells. This signal transduction is dependent on the cytoplasmic domain, which consists of 213 amino acids. In contrast to the type I receptor, the type II IL-1R has a small cytoplasmic tail, and it is not clear whether this receptor is a signal-transducing or a regulatory molecule. Here we report that the type II IL-1R does not mediate gene activation in Jurkat cells. However, a hybrid receptor composed of the extracellular and transmembrane regions of the human type II interleukin-1 fused to the cytoplasmic domain of the human type I IL-1R was capable of transducing a signal across the membrane resulting in a pattern of gene activation identical to that mediated by the type I IL-1R. Our results indicated that the extracellular domain of the type II IL-1R was capable of functionally interacting with interleukin-1 and transmitting the resulting signal to a heterologous cytoplasmic domain.