Serotonin transporters (SERT) are specialized membrane proteins located on presynaptic serotonergic neurons that regulate serotonin neurotransmission by reabsorbing serotonin (5-hydroxytryptamine, 5-HT) from the synaptic cleft back into the nerve terminal after its release. This reuptake process terminates serotonin signaling and maintains neurotransmitter homeostasis in the central nervous system. Serotonin transporters are the primary targets of selective serotonin reuptake inhibitors (SSRIs) and several other antidepressants, which inhibit serotonin reuptake, increase synaptic serotonin levels, and enhance serotonergic neurotransmission to treat depression, anxiety disorders, and other psychiatric conditions.