Fig. 1. Controlled dimerization of artificial membrane receptors for transmembrane signal transduction. The S1 monomer was composed of three DNA modules: A1, L1, and G1; the S2 monomer was composed of three DNA modules: A2, L2, and G2. While A1 and A2 are the split sequences of an ATP-binding aptamer, G1 and G2 are the split sequences of a G-quadruplex. ATP triggers the oligo-dimerization of artificial DNA receptors on the membrane, which are coupled to the G-quadruplex-mediated peroxidation of Amplex Red to resorufin and fluorescence signal output on the inside of the membrane.