Molecular drug targets membrane transporters

Passive diffusion, facilitated and active transport, and diffusion through channels account for most of the molecular transit across membranes. Several other mechanisms involving membrane-associated proteins are also important in the life of a cell, and represent important targets for drug therapy. 

Mechanisms of drug action. To mediate a response the drug can bind to the desired therapeutic target or to other molecular targets such as G-protein-coupled receptors (GPCRs), ion channels, or transporters on the cell membrane, or to intracellular targets such as enzymes and nuclear hormone receptors. 

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