Vesicular amine transporters 1 (VAT1) and 2 (VAT2), and similar transporters of the Major Facilitator Superfamily
Vesicular amine transporter 1 (VAT1 or VMAT1) is also called solute carrier family 18 member 1 (SLC18A1) or chromaffin granule amine transporter, while VAT2 (or VMAT2) is also called SLC18A2, synaptic vesicular amine transporter, or monoamine transporter. VATs (or VMATs) are responsible for the uptake of cytosolic monoamines into synaptic vesicles in monoaminergic neurons. VAT1 and VAT2 distinct pharmacological properties and tissue distributions. VAT1 is preferentially expressed in neuroendocrine cells and endocrine cells, where it transports biogenic monoamines, such as serotonin, from the cytoplasm into the secretory vesicles. VAT2 is primarily expressed in the CNS and is involved in the ATP-dependent vesicular transport of biogenic amine neurotransmitters including dopamine, norepinephrine, serotonin, and histamine into synaptic vesicles. VATs belong to the bacterial MdtG-like and eukaryotic solute carrier 18 (SLC18) family of the Major Facilitator Superfamily (MFS) of transporters. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.
Feature 1:putative chemical substrate binding pocket [chemical binding site]
Evidence:
Comment:based on the structures of MFS transporters with bound substrates, substrate analogs, and/or inhibitors
Comment:since MFS proteins facilitate the transport of many different substrates including ions, sugar phosphates, drugs, neurotransmitters, nucleosides, amino acids, and peptides, the residues involved in substrate binding may not be strictly conserved among superfamily members
Comment:the substrate binding site or translocation pore has access to both sides of the membrane in an alternating fashion through a conformational change of the MFS transporter
Jiyao W et al.(2023). "The conserved domain database in 2023.",