OVERVIEW OF DRUG TRANSPORTER FAMILIES

Drug transporters play important roles in the absorption, distribution, metabolism and excretion of drugs, pesticides, signaling molecules, heavy metal conjugates, components of phytomedicines, and toxins. Alterations in the expression and function of these transporters contribute to the intra- and inter-individual variability of the therapeutic efficacy and the toxicity of many drugs, and to many pathophysiological conditions. This chapter provides an overview of the classification of drug transporters including their structures, transport mechanisms, expression, nomenclature, and gene localization. Such knowledge will serve as a foundation, allowing readers to become familiar with the families of drug transporters prior to reading the following book chapters that describe the specific families of drug transporters, their molecular characterization, and role in the disposition of drugs and endogenous substrates.