In summary, the PfCRT protein binds CQ as is predicted from several models for its function. Azido-biotin-CQ now clearly defines that binding site and distinguishes drug binding preferences for various PfCRT isoforms [90] . CQ resistance-associated mutant PfCRT shows altered CQ binding, promotes altered diffusion of CQ and perturbs osmolyte equilibrium within the DV, which then alters DV pH and volume regulation.