The vesicular amine transporter family (SLC18): amine/proton antiporters required for vesicular accumulation and regulated exocytotic secretion of monoamines and acetylcholine.
The vesicular amine transporters (VATs) are expressed as integral proteins of the lipid bilayer membrane of secretory vesicles in neuronal and endocrine cells. Their function is to allow the transport of acetylcholine (by the vesicular acetylcholine transporter VAChT; SLC18A3) and biogenic amines (by the vesicular monoamine transporters VMAT1 and VMAT2; SLC18A1 and SLC18A2) into secretory vesicles, which then discharge them into the extracellular space by exocytosis. Transport of positively charged amines by members of the SLC18 family in all cases utilizes an electrochemical gradient across the vesicular membrane established by proton pumping into the vesicle via a vacuolar ATPase; the amine is accumulated in the vesicle at the expense of the proton gradient, at a ratio of one translocated amine per two translocated protons. The members of the SLC18 family have become important histochemical markers for chemical coding in neuroendocrine tissues and cells. The structural basis of their remarkable ability to transport positively charged amines against a very large concentration gradient, as well as potential disease association with impaired transporter function and expression, are under intense investigation.
Eiden
Lee E
LE
Section on Molecular Neuroscience, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, Building 36, Room 2A-11, 9000 Rockville Pike, Bethesda, MD 20892, USA. eiden@codon.nih.gov
Schäfer
Martin K-H
MK
Weihe
Eberhard
E
Schütz
Burkhard
B
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D005089:Exocytosis / Q000502:physiology*; D006801:Humans; D008562:Membrane Glycoproteins / Q000502:physiology*; D026901:Membrane Transport Proteins; D005810:Multigene Family / Q000502:physiology; D009479:Neuropeptides; D011522:Protons; D022142:Secretory Vesicles / Q000378:metabolism*; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009479:Neuropeptides; D011522:Protons; C493449:SLC18A1 protein, human; C493452:SLC18A2 protein, human; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins; D000109:Acetylcholine