A molecule, such as a protein, that a drug binds to in order to produce a therapeutic effect.A drug target is a specific molecule — usually a protein, but sometimes nucleic acid or other biomolecule — that a drug binds to in order to alter its activity and produce a therapeutic effect. The binding typically inhibits or activates the target's function, correcting a disease-causing pathway. Identifying and validating drug targets is the first critical step in drug discovery, as the target determines the drug's specificity and potential side effects.
Drugs interact with their targets through molecular recognition: the drug molecule fits into a binding site on the target, often mimicking a natural ligand or substrate. This interaction can block the target's activity (e.g., an enzyme inhibitor) or enhance it (e.g., a receptor agonist). The drug's efficacy depends on its affinity and selectivity for the target, and its therapeutic window is shaped by how uniquely the target is expressed in diseased versus healthy tissues.
Drug targets are the foundation of pharmaceutical development, from small-molecule drugs like aspirin (targeting COX enzymes) to biologics like monoclonal antibodies (targeting specific cell-surface receptors). Modern research also uses genetic screens and structural biology to discover new targets for diseases like cancer and Alzheimer's.
The most common drug targets are G-protein-coupled receptors (GPCRs), which are involved in nearly all physiological processes and are targeted by about 34% of all FDA-approved drugs.