A point mutation in the amino terminus of TLR7 abolishes signaling without affecting ligand binding. by Iavarone, C, Ramsauer, K, Kubarenko, A, Debasitis, J, Leykin, I, Weber, A, Siggs, O, Beutler, B, Zhang, P, Otten, G, D'Oro, U, Valiante, N, Mbow, M, Visintin, A