SLC22A3
Description
The SLC22A3 (solute carrier family 22 member 3) is a protein-coding gene located on chromosome 6.
Solute carrier family 22 member 3 (SLC22A3), also known as organic cation transporter 3 (OCT3) or extraneuronal monoamine transporter (EMT), is a protein that in humans is encoded by the SLC22A3 gene. Polyspecific organic cation transporters in the liver, kidney, intestine, and other organs are critical for elimination of many endogenous small organic cations as well as a wide array of drugs and environmental toxins. This gene is one of three similar cation transporter genes located in a cluster on chromosome 6. The encoded protein contains twelve putative transmembrane domains and is a plasma integral membrane protein. OCT3 is widely distributed in brain tissue. It is not yet completely clear whether its location is primarily neuronal or glial. Areas of the brain in which it has been reported include: hippocampus, retrosplenial cortex, visual cortex, hypothalamus, amygdala, nucleus accumbens, thalamus, raphe nucleus, subiculum, superior and inferior colliculi, and islands of Calleja. Organic cation transporter 3 is a polyspecific transporter whose transport is independent of sodium. Known substrates for transport include: histamine, serotonin, norepinephrine, dopamine and MPP+. Capacity for transport and affinity for these substrates may vary between rat and human isoforms however.
SLC22A3, also known as OCT3, is an electrogenic voltage-dependent transporter that moves various organic cations across cell membranes. This includes endogenous bioactive amines, cationic drugs, and xenobiotics. Its transport activity is driven by the electrochemical potential, meaning it's influenced by the membrane potential and concentration gradients. It acts as a uniporter, meaning it doesn't require sodium or chloride ions to transport substrates. OCT3 is involved in the uptake of monoamine neurotransmitters such as dopamine, adrenaline/epinephrine, noradrenaline/norepinephrine, histamine, serotonin, and tyramine, playing a role in the regulation of aminergic neurotransmission in the brain. It also transports dopaminergic neuromodulators cyclo(his-pro) and salsolinol, although with low efficiency. OCT3 likely participates in the renal clearance of cationic compounds from the blood flow, and may regulate the transport of such compounds across the blood-testis barrier. It also transports the polyamines spermidine and putrescine, and mediates the bidirectional transport of agmatine. It also transports guanidine. OCT3 may play a role in intracellular transport of organic cations, contributing to amine metabolism and intracellular signaling.
SLC22A3 is also known as EMT, EMTH, OCT3.
