Model of interaction of the IL‐1 receptor accessory protein IL‐1RAcP with the IL‐1β/IL‐1RI complex

Abstract
A preliminary model has been calculated for the activating interaction of the interleukin 1 receptor (IL-1R) accessory protein IL-1RAcP with the ligand/receptor complex IL-1β/IL-1RI. First, IL-1RAcP was modeled on the crystal structure of IL-1RI bound to IL-1β. Then, the IL-1RAcP model was docked using specific programs to the crystal structure of the IL-1β/IL-1RI complex. Two types of models were predicted, with comparable probability. Experimental data obtained with the use of IL-1β peptides and antibodies, and with mutated IL-1β proteins, support the BACK model, in which IL-1RAcP establishes contacts with the back of IL-1RI wrapped around IL-1β.