Monoamine Transporter

Monoamine transporters (MATs) belong to the solute carrier 6 (SLC6) family of human transporters, which, in turn, is a subfamily of the broader neurotransmitter:sodium symporters (NSSs) that comprise transporters from prokaryotic to human. MATs comprise three main members-the dopamine (DA) transporter (DAT), serotonin transporter (SERT) and norepinephrine transporter (NET). MATs regulate neurotransmission via the reuptake of dopamine, serotonin and norepinephrine from extra-neuronal regions and thus maintain neurotransmitter homeostasis.

MATs are transmembrane proteins located in plasma membranes of monoaminergic neurons. These proteins use ion (Na⁺, Cl⁻) gradients as energy sources to move monoamines into or out of neurons. In the membrane of intracellular synaptic vesicles is the vesicular monoamine transporters 1 and 2 (VMAT1 and VMAT2), which use a proton gradient as the energy source to sequester cytosolic monoamines into the vesicles and then release the monoamines into synaptic cleft by exocytosis. Dysregulation of MATs has been linked to depression, anxiety disorder, attention-deficit-hyperactivity disorder, obsessive-compulsive disorder, substance-use disorders, epilepsy, Parkinson’s disease and autism-spectrum disorder. Thus, MATs serve as pharmacological targets for several neuropsychiatric and neurodegenerative disorders.