Molecular aspects of the translocation process by ABC proteins

ATP binding cassette (ABC) proteins are found in all levels of life and harbor a major responsibility for mediating cellular transport processes. The ABC proteins mediate import and export processes primarily as primary active transporters, although members are known to act as ion channels or regulators. Substrates for ABC transporters encompass most biochemical classes, both endogenous and exogenous. Clearly, this family of transporters is a versatile one, and many ABC proteins are involved in pathological conditions. Consequently, a great deal of research effort has focused on understanding their cellular roles and overcoming their actions in disease states. This chapter focuses on the molecular mechanisms of transport by the ABC family.