Dimeric proteins are prominent in biology, and receptor dimerization (homo- or heterodimerization) is central to signal transduction. Herein, we report a network that responds to a membrane-associated dimeric protein with the uncaging of a powerful cytotoxic. The network is based on two ligands functionalized with peptide nucleic acids (PNAs) (templating strand and catalyst-functionalized strand, respectively) and a substrate with the caged cytotoxic (monomethyl auristatin E: MMAE; a high-affinity tubulin ligand). In the presence of the dimeric protein, the network yields a cooperative supramolecular assembly with a hybridization architecture that enhances the templated reaction and enables the uncaging of a substrate. The network was tested on cells that express a cancer biomarker, carbonic anhydrase IX, in response to hypoxia. The output of the network correlates with the expression of carbonic anhydrase IX, and this biomarker was harnessed to uncage a potent cytotoxic agent.