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Showing SLC6A1 — GAT1 is a alias.

SLC6A1

Sodium- and chloride-dependent GABA transporter 1 · UniProt P30531

Length
599 aa
Mass
67.1 kDa
Annotated
2026-06-10
6 papers cited in narrative 6 extracted findings
Cross-family judge vs UniProt: Affinage preferred

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

SLC6A1 encodes GAT-1, a plasma membrane GABA reuptake transporter whose principal disease mechanism is partial loss of transporter function: pathogenic variants strongly reduce GAT-1-mediated GABA uptake (mean −89.4%), and residual transporter activity correlates quantitatively with epilepsy severity and intellectual disability across patient cohorts [PMID:bio_10.1101_2025.11.06.687003, PMID:bio_10.1101_2025.04.01.24316792]. A Drosophila allelic series confirms that missense variants such as p.A334S act as hypomorphs producing graded neurological phenotypes, establishing haploinsufficiency with severity scaling to functional loss [PMID:bio_10.1101_2024.09.27.24314092]. Beyond its synaptic reuptake role, GAT-1 is required cell-autonomously for migration of MGE-derived interneurons during cortical development, as shown in fused human organoid models [PMID:bio_10.1101_2025.07.01.662594]. SLC6A1 expression is set transcriptionally through SMARCC2-dependent H3K9 acetylation at its promoter, and the molecular chaperone 4-phenylbutyric acid partially restores uptake by deficient transporters [PMID:bio_10.1101_2025.11.06.687003, PMID:bio_10.1101_2025.05.29.656867].

Mechanistic history

Synthesis pass · year-by-year structured walk · 6 steps
  1. 2024 Low

    Computational modeling sought to define which transporter residues govern ligand binding and selectivity among GABA transporter subtypes, addressing the basis of subtype-specific pharmacology.

    Evidence Proteochemometric modeling across four GABA transporter subtypes using 323 compounds with descriptor importance analysis

    PMID:bio_10.1101_2024.08.13.607728

    Open questions at the time
    • Computational prediction only; no experimental mutagenesis or binding validation
    • Identified position is in BGT1 numbering, not directly tested in GAT-1
    • No functional consequence for human variants established
  2. 2025 Medium

    To define the disease mechanism, functional assays asked whether pathogenic SLC6A1 variants impair GABA uptake and whether activity could be pharmacologically restored, establishing loss-of-function with a candidate therapeutic correction.

    Evidence iGABA-Snfr fluorescence sensor uptake assay cross-validated against [3H]-GABA uptake in cells expressing variants, plus 4PBA rescue

    PMID:bio_10.1101_2025.11.06.687003

    Open questions at the time
    • Single lab; cell-based overexpression rather than endogenous context
    • 4PBA rescue mechanism (chaperone-mediated trafficking) not directly demonstrated
    • Not all variant classes covered by the same readout
  3. 2025 Medium

    An in vivo allelic series tested whether SLC6A1 acts through haploinsufficiency and whether clinical severity tracks residual activity, confirming a graded hypomorphic mechanism.

    Evidence Drosophila allelic series expressing human variants with motor/neurological phenotyping

    PMID:bio_10.1101_2024.09.27.24314092

    Open questions at the time
    • Ortholog-based model; mammalian validation of individual variants not shown
    • Single lab
    • Quantitative mapping of fly phenotype to human severity indirect
  4. 2025 Medium

    A multi-center cohort connected functionally measured transporter activity to clinical outcome, establishing a genotype-function-phenotype quantitative relationship.

    Evidence GABA uptake functional validation correlated with epilepsy severity and intellectual disability in 708 individuals

    PMID:bio_10.1101_2025.04.01.24316792

    Open questions at the time
    • Single assay type for transporter activity
    • Correlation does not isolate other genetic modifiers
    • Mechanistic link between reuptake loss and ID not resolved
  5. 2025 Medium

    Organoid modeling asked whether GAT-1 has a developmental role beyond synaptic reuptake, revealing a cell-autonomous requirement for interneuron migration.

    Evidence hPSC-derived MGE organoids fused with cortical organoids, transcriptomics and electrophysiology under SLC6A1 loss-of-function

    PMID:bio_10.1101_2025.07.01.662594

    Open questions at the time
    • Single method for the migration readout
    • Molecular mechanism coupling GAT-1 to migration unknown
    • Not validated in vivo
  6. 2025 Medium

    Chromatin profiling identified an upstream transcriptional regulator of SLC6A1, showing that SMARCC2-dependent histone acetylation controls GAT-1 expression and GABAergic transmission.

    Evidence H3K9ac ChIP-seq at Slc6a1 promoter, RNA-seq/qPCR, GABAergic current recordings, and romidepsin rescue in Smarcc2-deficient mouse PFC

    PMID:bio_10.1101_2025.05.29.656867

    Open questions at the time
    • Demonstrated in mouse PFC; human relevance inferred
    • Direct vs indirect SMARCC2 action at the promoter not fully resolved
    • Single lab

Open questions

Synthesis pass · forward-looking unresolved questions
  • How loss of GAT-1 GABA reuptake mechanistically produces intellectual disability, and the molecular pathway linking GAT-1 to interneuron migration, remain undefined.
  • No structural model of human GAT-1 variant effects experimentally validated
  • Migration mechanism unexplained
  • Therapeutic durability of 4PBA/chaperone rescue untested in vivo

Mechanism profile

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

Evidence

Reading pass · 6 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2025 Pathogenic SLC6A1 variants strongly reduce GAT-1-mediated GABA uptake (mean –89.4%), as measured by a fluorescence-based iGABA-Snfr sensor assay; variant-specific uptake reductions were highly correlated with radioactive [3H]-GABA uptake results (R²=0.8095). The molecular chaperone 4-phenylbutyric acid (4PBA) increased GAT-1-mediated GABA uptake by ~35%. High-content fluorescence imaging assay using genetically encoded GABA sensor (iGABA-Snfr) in cells expressing SLC6A1 variants; validated against radioactive [3H]-GABA uptake assay bioRxivpreprint Medium bio_10.1101_2025.11.06.687003
2025 SLC6A1 haploinsufficiency results in a partial loss-of-function mechanism; a Drosophila allelic series confirmed that missense variants (including p.A334S) cause hypomorphic phenotypes consistent with reduced GAT-1 activity, with clinical severity correlating with degree of functional loss. Drosophila melanogaster allelic series expressing SLC6A1 variants; phenotypic characterization of motor and neurological phenotypes bioRxivpreprint Medium bio_10.1101_2024.09.27.24314092
2025 SLC6A1 deficiency in human MGE organoids causes a migration deficit of MGE-derived interneurons when fused with cortical organoids, indicating a cell-autonomous role for GAT-1 in interneuron migration during development. hPSC-derived MGE organoids fused with cortical organoids; transcriptomic analysis and electrophysiology; SLC6A1 loss-of-function disease model bioRxivpreprint Medium bio_10.1101_2025.07.01.662594
2025 SLC6A1 genotypes with reduced GAT1 transporter activity are quantitatively linked to epilepsy severity and intellectual disability, with functionally validated SLC6A1 variants showing loss of GABA reuptake activity. Functional validation of SLC6A1 variants by GABA uptake assays; correlation of transporter activity with clinical severity in a cohort of 708 individuals bioRxivpreprint Medium bio_10.1101_2025.04.01.24316792
2025 Smarcc2 deficiency in mouse prefrontal cortex reduces histone acetylation (H3K9ac) at the Slc6a1 (GAT1) promoter, leading to downregulation of Slc6a1 expression and impaired GABAergic synaptic currents; this was rescued by the HDAC inhibitor romidepsin. ChIP-seq for H3K9ac at Slc6a1 promoter; RNA-seq and qPCR in Smarcc2-deficient mouse PFC; electrophysiological recordings of GABAergic currents; romidepsin rescue experiment bioRxivpreprint Medium bio_10.1101_2025.05.29.656867
2024 Proteochemometric modeling identified amino acid Q299 (in BGT1 numbering; corresponding position in GAT1 is L300) as relevant for ligand binding and subtype selectivity among GABA transporter subtypes (GAT1/BGT1/GAT2/GAT3). Proteochemometric modeling (partial least squares and random forest) using dataset of 323 compounds with bioactivity data across four GABA transporter subtypes; protein descriptor importance analysis bioRxivpreprint Low bio_10.1101_2024.08.13.607728

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