9kqa
From Proteopedia
Cryo-EM structure of human VMAT2 in complex with Tetrabenazine
Structural highlights
DiseaseVMAT2_HUMAN Brain dopamine-serotonin vesicular transport disease. The disease is caused by variants affecting the gene represented in this entry. FunctionC562_ECOLX Electron-transport protein of unknown function.VMAT2_HUMAN Electrogenic antiporter that exchanges one cationic monoamine with two intravesicular protons across the membrane of secretory and synaptic vesicles. Uses the electrochemical proton gradient established by the V-type proton-pump ATPase to accumulate high concentrations of monoamines inside the vesicles prior to their release via exocytosis. Transports a variety of catecholamines such as dopamine, adrenaline and noradrenaline, histamine, and indolamines such as serotonin (PubMed:23363473, PubMed:8643547). Regulates the transvesicular monoaminergic gradient that determines the quantal size. Mediates somatodendritic dopamine release in hippocampal neurons, likely as part of a regulated secretory pathway that integrates retrograde synaptic signals (By similarity). Acts as a primary transporter for striatal dopamine loading ensuring impulse-dependent release of dopamine at the synaptic cleft (By similarity). Responsible for histamine and serotonin storage and subsequent corelease from mast cell granules (By similarity) (PubMed:8860238).[UniProtKB:Q01827][UniProtKB:Q8BRU6][1] [2] [3] Publication Abstract from PubMedVesicular monoamine transporter 2 (VMAT2) is crucial for packaging monoamine neurotransmitters into synaptic vesicles, with their dysregulation linked to schizophrenia, mood disorders, and Parkinson's disease. Tetrabenazine (TBZ) and valbenazine (VBZ), both FDA-approved VMAT2 inhibitors, are employed to treat chorea and tardive dyskinesia (TD). Our study presents the structures of VMAT2 bound to substrates serotonin (5-HT) and dopamine (DA), as well as the inhibitors TBZ and VBZ. Utilizing cryo-electron microscopy (cryo-EM), mutagenesis functional assays, and molecular dynamics (MD) simulations, we elucidate the mechanisms of substrate transport and drug inhibition. Our MD simulations indicate potential binding poses of substrate (5-HT) in both cytosol-facing and lumen-facing states, emphasizing the significance of protonation of key acidic residues for substrate release. We demonstrate that TBZ locks VMAT2 in a lumen-facing occluded state, while VBZ stabilizes it in a lumen-facing conformation. These insights enhance our understanding of VMAT2 function and provide valuable insights for the development of novel therapeutic strategies for psychiatric disorders. Drug inhibition and substrate transport mechanisms of human VMAT2.,Wei F, Liu H, Zhang W, Wang J, Zhang Y Nat Commun. 2025 Jan 2;16(1):323. doi: 10.1038/s41467-024-55361-0. PMID:39747030[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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