Overview Of Drug TranspOrTer families

Transporters are membrane proteins whose primary function is to facilitate the flux of molecules into and out of cells. Drug transporters did not evolve to transport specific drugs. Instead, their primary functions are to transport nutrients or endogenous substrates, such as sugars, amino acids, nucleotides, and vitamins, or to protect the body from dietary and environmental toxins. However, the specificity of these transporters is not strictly restricted to their physiological substrates. Drugs that bear significant structural similarity to the physiological substrates have the potential to be recognized and transported by these transporters. As a consequence, these transporters also play significant roles in determining the bioavailability, therapeutic efficacy, and pharmacokinetics of a variety of drugs. Nevertheless, because drugs may compete with the physiological substrates of these transporters, they are also likely to interfere with the transport of endogenous substrates and consequently produce deleterious effects on body homeostasis.