Affinage

SLC32A1

Vesicular inhibitory amino acid transporter · UniProt Q9H598

Length
525 aa
Mass
57.4 kDa
Annotated
2026-06-10
40 papers in source corpus 11 papers cited in narrative 11 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

SLC32A1 (VGAT/VIAAT) is the vesicular transporter that loads inhibitory neurotransmitters into synaptic vesicles of GABAergic and glycinergic nerve terminals, and it was the founding member of a distinct vesicular amino acid transporter gene family (PMID:9822734). It mediates vesicular uptake of both GABA and glycine, with the inhibitory phenotype of a terminal set by competition between the two amino acids for transport, itself governed by cytosolic substrate concentrations established by co-expressed plasmalemmal transporters such as GlyT2 (PMID:17554001). VGAT is essential for inhibitory transmission: its genetic loss abolishes both GABAergic and glycinergic IPSCs (PMID:25545713), whereas partial reduction selectively curtails glycinergic mini-events by shrinking the readily releasable pool of glycine vesicles (PMID:22275517). Through VGAT-dependent inhibitory release, the transporter shapes circuit development, supporting palatogenesis via central GABAergic circuits (PMID:20333300), inhibitory synapse formation from ErbB4+/PV+ interneurons onto excitatory neurons (PMID:29431653), and normal seizure threshold (PMID:32954490). De novo missense variants in SLC32A1 impair GABAergic neurotransmission through two distinct mechanisms: variants in helices lining the GABA transport pathway reduce vesicular quantal size, while an N-terminal variant increases presynaptic release probability (PMID:36073542). VGAT expression is post-transcriptionally repressible, as tau-driven miR-92a targets the vGAT 3' UTR to suppress translation and reduce GABAergic inhibition (PMID:28129110).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 1998 High

    Established the molecular identity and subcellular home of the vesicular inhibitory transporter, defining VGAT as a synaptic-vesicle protein of GABAergic and glycinergic terminals.

    Evidence Quantitative immunogold EM with epitope-specific antibodies and triple labeling for VGAT, GABA, and glycine in rat CNS

    PMID:9822734

    Open questions at the time
    • Localization alone did not demonstrate transport activity
    • Substrate specificity not yet resolved
  2. 2007 High

    Resolved how a single transporter handles two substrates, showing that glycine vs GABA loading is set by competition driven by cytosolic concentrations from plasmalemmal transporters.

    Evidence Reconstitution in neuroendocrine cells with GlyT1/GlyT2/GABA transporters, double-sniffer patch-clamp quantal measurements, and UNC-47 ortholog mutagenesis

    PMID:17554001

    Open questions at the time
    • Did not define the structural basis of dual-substrate recognition
    • Coupling to the proton gradient inferred but not directly dissected here
  3. 2010 High

    Placed VGAT function in a developmental pathway, showing its CNS action drives palatogenesis rather than a local tissue role.

    Evidence Oral explant cultures, muscimol pharmacological rescue, CNS-specific conditional Gad1 knockout, and Viaat germline knockout mice

    PMID:20333300

    Open questions at the time
    • Identity of the central circuits coupling inhibitory transmission to palate development unresolved
    • Mechanism downstream of GABA-A signaling not mapped
  4. 2012 High

    Demonstrated dose-sensitivity of VGAT, with partial loss selectively impairing glycinergic over GABAergic mini-events.

    Evidence Heterozygous VGAT knockout mice with mIPSC patch-clamp, Western blot, HPLC amino acid quantification, and pain behavior assays

    PMID:22275517

    Open questions at the time
    • Why glycinergic transmission is preferentially vulnerable to reduced VGAT not fully explained
    • Restricted to dorsal horn neurons
  5. 2014 High

    Established VGAT as strictly required for vesicular release of both GABA and glycine and ranked its loss against GAD isoform losses in development.

    Evidence VGAT, GAD67, and GAD65/67 double knockout mice with IPSC electrophysiology and anatomical phenotyping

    PMID:25545713

    Open questions at the time
    • Does not separate developmental from acute physiological requirements
    • Tissue-level mechanism of omphalocele/cleft palate not detailed
  6. 2015 Medium

    Revealed that VGAT can be co-sorted with VGLUT1 into shared vesicles, enabling activity-regulated co-release of glutamate and GABA.

    Evidence Confocal immunofluorescence co-localization and electrophysiology with sequential receptor blockers under network-activity manipulation in rat cortical neurons

    PMID:25749864

    Open questions at the time
    • Molecular mechanism of co-sorting unknown
    • Functional significance for circuit output not established
  7. 2017 Medium

    Identified a post-transcriptional control point, showing tau-induced miR-92a represses VGAT translation to weaken inhibition.

    Evidence Luciferase 3' UTR reporter, Western blot, GABA ELISA, eIPSP electrophysiology, and in vivo antagomir rescue in mouse hippocampus

    PMID:28129110

    Open questions at the time
    • Generalizability beyond tau pathology contexts unclear
    • Other regulators of VGAT translation not surveyed
  8. 2018 Medium

    Showed cell-type-specific VGAT requirement for inhibitory synapse development from ErbB4+/PV+ interneurons onto excitatory neurons.

    Evidence ErbB4-Cre conditional Vgat knockout mice with immunohistochemistry and inhibitory neurotransmission electrophysiology

    PMID:29431653

    Open questions at the time
    • Link between perineuronal net increase and altered inhibition not mechanistically resolved
    • Single interneuron lineage examined
  9. 2018 Medium

    Demonstrated that disrupting the VGAT locus impairs hippocampal GABAergic transmission and predisposes to epilepsy.

    Evidence VGAT-Cre knock-in mice analyzed by qPCR, Western blot, electrophysiology, and EEG kindling

    PMID:32954490

    Open questions at the time
    • Confound of Cre insertion as a tool line rather than a designed disease model
    • Threshold of VGAT reduction needed for seizure susceptibility undefined
  10. 2018 Low

    Reported an unexpected non-vesicular VGAT localization at the plasma membrane of renal distal tubule cells, hinting at a paracrine GABA role outside synapses.

    Evidence Immuno-DAB and immunogold electron microscopy in mouse kidney

    PMID:30448467

    Open questions at the time
    • Single localization study without functional consequence established
    • No transport or signaling assay in kidney
    • Not independently confirmed
  11. 2022 High

    Connected SLC32A1 to human disease, defining two distinct mechanisms by which de novo variants impair GABAergic transmission.

    Evidence Functional evaluation of patient-derived variants in murine neurons, in silico structural modeling, quantal size measurement, and high-frequency stimulation electrophysiology

    PMID:36073542

    Open questions at the time
    • High-resolution structure of the transport pathway absent
    • Mechanism by which the N-terminal variant raises release probability not detailed

Open questions

Synthesis pass · forward-looking unresolved questions
  • How VGAT couples the vesicular proton gradient to dual GABA/glycine transport at atomic resolution, and whether its non-synaptic localizations carry physiological function, remain open.
  • No experimental structure of the transport pathway
  • Functional role of renal/plasma-membrane VGAT untested
  • Stoichiometry of proton coupling not measured

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005215 transporter activity 4
Localization
GO:0031410 cytoplasmic vesicle 2 GO:0005886 plasma membrane 1
Pathway
R-HSA-112316 Neuronal System 4 R-HSA-1266738 Developmental Biology 3

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1998 VGAT (SLC32A1) protein specifically associates with synaptic vesicles in GABAergic and glycinergic nerve endings, as demonstrated by post-embedding immunogold quantification in rat CNS. It is the first vesicular amino acid transporter molecularly identified and defines a novel gene family distinct from other vesicular neurotransmitter transporters. Immunogold electron microscopy with epitope-specific antibodies (N- and C-terminal); triple immunolabeling for VGAT, GABA, and glycine The Journal of neuroscience High 9822734
2007 VIAAT (SLC32A1) mediates vesicular loading of both glycine and GABA; the vesicular inhibitory phenotype (glycinergic vs GABAergic) is determined by competition between glycine and GABA for uptake by VIAAT, modulated by cytosolic amino acid concentrations established by plasmalemmal transporters. GlyT2 is more effective than GlyT1 in supporting glycinergic vesicular release because GlyT2 cannot operate in reverse mode, maintaining higher cytosolic glycine for VIAAT loading. Reconstitution in neuroendocrine cells expressing VIAAT with GlyT1, GlyT2, or GABAergic transporters; quantal release measured by double-sniffer patch-clamp technique; point mutation of UNC-47 (C. elegans VIAAT ortholog) The Journal of neuroscience High 17554001
2012 Reduced VGAT expression in heterozygous VGAT knockout mice selectively impairs glycinergic (not GABAergic) miniature inhibitory postsynaptic currents in spinal cord dorsal horn neurons, reducing both frequency and amplitude of glycinergic mIPSCs and shrinking the readily releasable pool of glycine-containing vesicles, leading to enhanced inflammatory pain. Heterozygous VGAT knockout mouse model; patch-clamp recording of mIPSCs in dorsal horn neurons; Western blot; behavioral assays; HPLC for amino acid content Molecular pharmacology High 22275517
2010 VIAAT (SLC32A1) function in the CNS, not in the palate tissue itself, is required for normal palatogenesis. CNS-specific inactivation of Viaat is sufficient to cause cleft palate, and GABA-A receptor agonist muscimol rescues cleft palate in Viaat mutant embryos, indicating that vesicular inhibitory transmission acts through central GABAergic circuits to support palate development. Oral explant cultures; pharmacological rescue with muscimol; CNS-specific conditional Gad1 knockout; Viaat germline knockout mouse PloS one High 20333300
2014 VGAT knockout mouse cultured neurons and spinal cord show virtually no GABAergic or glycinergic inhibitory postsynaptic currents, establishing that VGAT is essential for vesicular loading and release of both GABA and glycine. Genetic epistasis with GAD67 and GAD65/67 double knockouts shows that both GABAergic (via both GAD isoforms) and glycinergic transmission contribute to palate and abdominal wall development, with VGAT loss producing the most severe phenotype. VGAT knockout, GAD67 knockout, and GAD65/GAD67 double knockout mice; electrophysiology (IPSC recording); anatomical phenotyping (cleft palate, omphalocele severity) Neuroscience High 25545713
2015 In rat primary cortical neurons, VGLUT1 and VGAT (SLC32A1) are co-sorted into the same synaptic vesicles in a subset of axon terminals, enabling co-release of glutamate and GABA from the same terminal. These mixed synapses are regulated in an activity-dependent manner: reducing network excitation decreases VGLUT1/VGAT co-expressing terminals, while blocking inhibition increases them. Immunofluorescence confocal microscopy; electrophysiology with consecutive application of selective glutamate and GABA-A receptor blockers; pharmacological manipulation of network activity Journal of cell science Medium 25749864
2018 Conditional deletion of Vgat from ErbB4+ interneurons reduces inhibitory axo-somatic and axo-axonic synapses from PV+/ErbB4+ interneurons onto excitatory neurons and alters inhibitory neurotransmission, demonstrating that VGAT-dependent GABA release from interneurons is required for the development of inhibitory synapses onto excitatory neurons. Perineuronal nets were increased in the cortex of ErbB4-Vgat-/- mice. Conditional (ErbB4-Cre) Vgat knockout mice; immunohistochemistry; electrophysiology for inhibitory neurotransmission The Journal of neuroscience Medium 29431653
2022 De novo missense variants in SLC32A1 located in helices lining the putative GABA transport pathway reduce quantal size, consistent with impaired filling of synaptic vesicles with GABA. A fourth variant in the N-terminus does not affect quantal size but increases presynaptic release probability, causing more severe synaptic depression during high-frequency stimulation. Thus, SLC32A1 variants can impair GABAergic neurotransmission through at least two distinct mechanisms. Functional evaluation of patient-derived variants in murine neuronal cell culture; in silico structural modeling; quantal size measurements; high-frequency stimulation electrophysiology Annals of neurology High 36073542
2018 In VGAT-Cre mice, insertion of Cre recombinase into the VGAT locus disrupts VGAT mRNA and protein expression, impairing GABAergic synaptic transmission in the hippocampus and predisposing mice to epilepsy after mild electrical kindling. Quantitative PCR; immunocytochemistry; Western blot; electrophysiology; EEG kindling model Epilepsia Medium 32954490
2018 VIAAT (SLC32A1) immunoreactivity is localized to basal infoldings and basal portions of lateral plasma membranes of distal tubular epithelial cells in mouse kidney, not in vesicles or vacuoles within these cells, suggesting a non-vesicular, paracrine/autocrine function in renal GABA signaling. Immunohistochemistry (immuno-DAB and immuno-gold electron microscopy) in mouse kidney tissue Annals of anatomy Low 30448467
2017 Accumulation of human tau in mouse hippocampus increases miR-92a, which targets the vGAT mRNA 3' UTR and inhibits vGAT (SLC32A1) translation, selectively suppressing vGAT protein expression among GABA-related factors and reducing extracellular GABA levels and GABAergic inhibitory postsynaptic potentials. Luciferase reporter assay for miR-92a targeting of vGAT 3' UTR; Western blot; GABA ELISA; electrophysiology (eIPSP); antagomir rescue experiments in vivo Molecular therapy Medium 28129110

Source papers

Stage 0 corpus · 40 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1998 The vesicular GABA transporter, VGAT, localizes to synaptic vesicles in sets of glycinergic as well as GABAergic neurons. The Journal of neuroscience : the official journal of the Society for Neuroscience 501 9822734
2009 Fluorescent labeling of both GABAergic and glycinergic neurons in vesicular GABA transporter (VGAT)-venus transgenic mouse. Neuroscience 110 19766173
2007 The transporters GlyT2 and VIAAT cooperate to determine the vesicular glycinergic phenotype. The Journal of neuroscience : the official journal of the Society for Neuroscience 73 17554001
2017 Correcting miR92a-vGAT-Mediated GABAergic Dysfunctions Rescues Human Tau-Induced Anxiety in Mice. Molecular therapy : the journal of the American Society of Gene Therapy 45 28129110
2006 Vesicular glutamate (VGlut), GABA (VGAT), and acetylcholine (VACht) transporters in basal forebrain axon terminals innervating the lateral hypothalamus. The Journal of comparative neurology 44 16572456
2022 Investigating the Role of GABA in Neural Development and Disease Using Mice Lacking GAD67 or VGAT Genes. International journal of molecular sciences 40 35887307
2015 Gestational and early postnatal hypothyroidism alters VGluT1 and VGAT bouton distribution in the neocortex and hippocampus, and behavior in rats. Frontiers in neuroanatomy 37 25741243
2010 Developmental localization of potassium chloride co-transporter 2 (KCC2), GABA and vesicular GABA transporter (VGAT) in the postnatal mouse somatosensory cortex. Neuroscience research 34 20219572
2014 GAD65/GAD67 double knockout mice exhibit intermediate severity in both cleft palate and omphalocele compared with GAD67 knockout and VGAT knockout mice. Neuroscience 30 25545713
2018 VGAT and VGLUT2 expression in MCH and orexin neurons in double transgenic reporter mice. IBRO reports 28 30155524
2014 GABAergic and glycinergic inhibitory synaptic transmission in the ventral cochlear nucleus studied in VGAT channelrhodopsin-2 mice. Frontiers in neural circuits 26 25104925
2018 Regulation of Synapse Development by Vgat Deletion from ErbB4-Positive Interneurons. The Journal of neuroscience : the official journal of the Society for Neuroscience 25 29431653
2011 Expression of VGluT1 and VGAT mRNAs in human dorsolateral prefrontal cortex during development and in schizophrenia. Brain research 23 21396926
2015 Co-expression of VGLUT1 and VGAT sustains glutamate and GABA co-release and is regulated by activity in cortical neurons. Journal of cell science 22 25749864
2010 Cleft palate is caused by CNS dysfunction in Gad1 and Viaat knockout mice. PloS one 22 20333300
2018 Functionally Complete Excision of Conditional Alleles in the Mouse Suprachiasmatic Nucleus by Vgat-ires-Cre. Journal of biological rhythms 21 29671710
2016 Alterations in hypoglossal motor neurons due to GAD67 and VGAT deficiency in mice. Experimental neurology 21 27956032
2012 Impaired glycinergic synaptic transmission and enhanced inflammatory pain in mice with reduced expression of vesicular GABA transporter (VGAT). Molecular pharmacology 21 22275517
2022 De Novo Missense Variants in SLC32A1 Cause a Developmental and Epileptic Encephalopathy Due to Impaired GABAergic Neurotransmission. Annals of neurology 20 36073542
2020 Characterization of kindled VGAT-Cre mice as a new animal model of temporal lobe epilepsy. Epilepsia 15 32954490
2015 Electrophysiological and morphological properties of neurons in the prepositus hypoglossi nucleus that express both ChAT and VGAT in a double-transgenic rat model. The European journal of neuroscience 15 25808645
2021 Association of SLC32A1 Missense Variants With Genetic Epilepsy With Febrile Seizures Plus. Neurology 14 34038384
2017 Few, Activity-Dependent, and Ubiquitous VGLUT1/VGAT Terminals in Rat and Mouse Brain. Frontiers in cellular neuroscience 14 28848395
2020 VGLUT-VGAT expression delineates functionally specialised populations of vasopressin-containing neurones including a glutamatergic perforant path-projecting cell group to the hippocampus in rat and mouse brain. Journal of neuroendocrinology 13 31944441
2012 Ontogenetic changes in the distribution of the vesicular GABA transporter VGAT correlate with the excitation/inhibition shift of GABA action. Neurochemistry international 13 22490609
2017 Inhibitory neuron-specific Cre-dependent red fluorescent labeling using VGAT BAC-based transgenic mouse lines with identified transgene integration sites. The Journal of comparative neurology 12 29063602
2018 Age-related loss of VGLUT1 excitatory, but not VGAT inhibitory, immunoreactive terminals on motor neurons in spinal cords of old sarcopenic male mice. Biogerontology 11 30084046
2018 Repeated low level domoic acid exposure increases CA1 VGluT1 levels, but not bouton density, VGluT2 or VGAT levels in the hippocampus of adult mice. Harmful algae 7 30420019
2022 Examining ventral subiculum and basolateral amygdala projections to the nucleus accumbens shell: Differential expression of VGLuT1, VGLuT2 and VGaT in the rat. Neuroscience letters 6 36038028
2021 Preparation and Implantation of Electrodes for Electrically Kindling VGAT-Cre Mice to Generate a Model for Temporal Lobe Epilepsy. Journal of visualized experiments : JoVE 5 34487121
2005 Ethanol induces GAD67 and VGAT in slice cultures of newborn rat cerebral cortex. Neuroreport 5 15729141
2017 Transgene is specifically and functionally expressed in retinal inhibitory interneurons in the VGAT-ChR2-EYFP mouse. Neuroscience 4 28918256
2022 Postpartum State, but Not Maternal Caregiving or Level of Anxiety, Increases Medial Prefrontal Cortex GAD65 and vGAT in Female Rats. Frontiers in global women's health 3 35211693
2015 γHV68 vGAT: a viral pseudoenzyme pimping for PAMPs. Molecular cell 3 25839430
2018 Expression and localization of VIAAT in distal uriniferous tubular epithelium of mouse. Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft 2 30448467
2021 Nigrostriatal dopamine depletion promoted an increase in inhibitory markers (parvalbumin, GAD67, VGAT) and cold allodynia. Neuroscience letters 1 34311052
2007 Amino acid transporter (VIAAT, VGLUT2) and chloride cotransporter (KCC1, KCC2 and NKCC1) expression in the vestibular nuclei of intact and labyrinthectomized rat. Experimental brain research 1 17598093
2026 Downregulation of SLC32A1 Mediates the PAI-1 Pathway in Alleviating Hepatic Stellate Cell Activation and Liver Fibrosis. The Journal of endocrinology 0 42187065
2026 Treatment of spinal injury muscle spasticity by spinal subpial AAV9-GAD65/VGAT delivery: an efficacy and safety study in rat, pig and NHP. Molecular therapy : the journal of the American Society of Gene Therapy 0 42244183
2025 Control of Aedes albopictus populations by silencing of the vesicular GABA transporter (vgat) and the vesicular monoamine transporter (vmat) genes using recombinant Chlorella shRNA. Parasites & vectors 0 41088451

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