Affinage

KCTD12

BTB/POZ domain-containing protein KCTD12 · UniProt Q96CX2

Length
325 aa
Mass
35.7 kDa
Annotated
2026-06-10
24 papers in source corpus 16 papers cited in narrative 16 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 8/8 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

KCTD12 is an auxiliary subunit of GABAB receptors that shapes inhibitory neurotransmission by tuning receptor surface abundance and signaling kinetics (PMID:23843457, PMID:28713569). It associates with the GABAB1/GABAB2 heterodimer already in the endoplasmic reticulum through its N-terminal BTB/POZ domain, which binds the C-terminal region of GABAB2; both the BTB and C-terminal H1 domains independently tetramerize, giving the protein a compact multidomain architecture (PMID:23996491). By reducing constitutive receptor internalization, KCTD12 increases the magnitude of GABAB-mediated K+ (GIRK) currents, while simultaneously accelerating both activation and desensitization kinetics of these currents (PMID:23843457, PMID:28713569). This desensitization is cross-regulated by PKA-dependent phosphorylation of GABAB2 serine-892, which rearranges KCTD12 at the receptor to slow desensitization, and the receptor-KCTD12 assembly itself promotes tonic S892 phosphorylation, forming a feedback loop (PMID:25065880). KCTD12 is required for GABAB current desensitization in specific neuron types such as cholecystokinin-expressing hippocampal interneurons, and together with KCTD8 it facilitates axonal-terminal GABAB expression and presynaptic excitation in habenular cholinergic neurons (PMID:27073217, PMID:35017224). Through these actions KCTD12 controls intrinsic neuronal excitability and influences emotionality, fear learning, and stress-related behavior (PMID:25689571, PMID:33285230). Beyond the nervous system, KCTD12 acts in cell-cycle and cancer contexts: it interacts with CDK1 and activates CDK1 and Aurora kinase A to drive the G2/M transition through a CDC25B-dependent step, with Aurora A phosphorylating KCTD12 at serine-243 to establish a positive feedback loop (PMID:28869606, PMID:30872078). In colorectal cancer cells it suppresses stemness markers by inhibiting the ERK pathway, functioning upstream of ERK (PMID:26847701).

Mechanistic history

Synthesis pass · year-by-year structured walk · 16 steps
  1. 2013 High

    Established that KCTD12 is a GABAB receptor-associated subunit acting at the ER to limit receptor internalization and thereby amplify surface GABAB signaling, answering how an accessory protein controls receptor abundance.

    Evidence BiFC, metabolic labeling/glycosylation, Co-IP, BRET, and electrophysiology in KCTD12 KO/knockdown hippocampal neurons

    PMID:23843457

    Open questions at the time
    • Structural basis of the ER association not resolved
    • Mechanism by which internalization is reduced not defined at molecular detail
  2. 2013 Medium

    Defined the structural basis of the KCTD12-GABAB2 interaction, showing the N-terminal BTB/POZ domain binds GABAB2 and that BTB and H1 domains tetramerize independently.

    Evidence CD spectroscopy, binding assays, size-exclusion chromatography, secondary structure prediction

    PMID:23996491

    Open questions at the time
    • No mutagenesis to validate binding interface
    • No cell-based functional confirmation of the domain model
    • No high-resolution structure
  3. 2014 High

    Revealed cross-regulation between KCTD12-induced desensitization and PKA phosphorylation of GABAB2-S892, showing how receptor phosphorylation reciprocally tunes the auxiliary subunit's kinetic effect.

    Evidence Heterologous and neuronal electrophysiology with KCTD12 KO and S892A knock-in mice plus PKA pharmacology

    PMID:25065880

    Open questions at the time
    • Molecular conformational change of KCTD12 upon S892 phosphorylation not directly visualized
    • Kinase recruitment mechanism unresolved
  4. 2014 Medium

    Identified a non-receptor signaling role in zebrafish whereby Kctd12 negatively regulates the kinase Ulk2 to restrain habenular dendritogenesis and anxiety-like behavior.

    Evidence Zebrafish loss-of-function, Ulk2 proline-serine rich domain interaction mapping, dendritic morphometry, behavioral assays

    PMID:25329151

    Open questions at the time
    • Conservation of the Ulk2 interaction in mammals not shown
    • Direct biochemical binding not validated beyond domain mapping
  5. 2015 Medium

    Connected KCTD12 loss to elevated intrinsic excitability of hippocampal pyramidal neurons and altered emotional behavior, linking the molecular function to circuit-level and behavioral output.

    Evidence Slice electrophysiology in Kctd12-/- and Kctd12+/- mice with behavioral assays

    PMID:25689571

    Open questions at the time
    • Single lab
    • Causal chain from excitability change to behavior not dissected
  6. 2016 Medium

    Placed KCTD12 upstream of ERK as a suppressor of colorectal cancer cell stemness, extending its function beyond neuronal GABAB signaling.

    Evidence siRNA/overexpression, colony/spheroid assays, xenografts, ERK inhibitor (U0126) epistasis

    PMID:26847701

    Open questions at the time
    • Mechanism linking KCTD12 to ERK not biochemically defined
    • Direct ERK-pathway partner not identified
  7. 2017 High

    Demonstrated cell-type specificity of KCTD12-dependent GABAB current desensitization, showing it is required in CCK-expressing hippocampal interneurons.

    Evidence Whole-cell recordings in KCTD12-deficient mice with immunoelectron microscopy

    PMID:27073217

    Open questions at the time
    • Why some interneuron types depend on KCTD12 and others differ not explained
  8. 2017 Medium

    Showed human KCTD12 accelerates both activation and desensitization of GABAB-GIRK currents and enhances positive allosteric modulation, confirming kinetic control across species.

    Evidence Automated heterologous electrophysiology with human KCTD12 and KCTD12 KO mouse pharmacology

    PMID:28713569

    Open questions at the time
    • Single lab
    • Structural basis of kinetic acceleration not resolved
  9. 2017 Medium

    Uncovered a cell-cycle role in which KCTD12 binds and activates CDK1 and Aurora A via CDC25B to promote G2/M, with Aurora A phosphorylating KCTD12-S243 in a feedback loop.

    Evidence Co-IP/mass spectrometry, CDC25B siRNA epistasis, phosphorylation assays, cell-cycle analysis, xenografts

    PMID:28869606

    Open questions at the time
    • Direct CDK1 binding interface not mapped
    • Functional consequence of S243 phosphorylation not isolated
    • Single lab
  10. 2018 Medium

    Positioned KCTD12 as a tumor suppressor downstream of KIT in GISTs, where KIT negatively regulates its expression.

    Evidence Reciprocal KIT and KCTD12 siRNA knockdown with proliferation assays, qPCR, Western blot in GIST T1 cells

    PMID:29930747

    Open questions at the time
    • Mechanism of KIT-dependent KCTD12 repression unknown
    • Downstream effectors of KCTD12 in GIST not defined
  11. 2019 Medium

    Validated the KCTD12-CDK1 interaction as functionally required by showing its pharmacological disruption arrests cells in G2 and blocks colon cancer proliferation.

    Evidence FDA library drug screen, Co-IP-based interaction disruption (adefovir dipivoxil), cell-cycle and xenograft proliferation assays

    PMID:30872078

    Open questions at the time
    • Drug specificity for the interaction not fully excluded
    • Structural binding site not defined
  12. 2019 Medium

    Identified transcriptional control of KCTD12 via GSK-3/CREB, with lithium increasing and GADL1 decreasing its expression.

    Evidence GSK-3 inhibition, KCTD12 promoter reporter assays, GADL1 overexpression, lithium treatment in SH-SY5Y cells

    PMID:31311980

    Open questions at the time
    • In vivo relevance of this regulatory axis not established
    • Direct CREB occupancy on the promoter not shown
  13. 2019 Low

    Linked KCTD12 loss to enhanced melanoma stemness via a proposed CD271 (p75NTR) interaction.

    Evidence KCTD12 knockout cell lines, in vitro stemness assays, in vivo metastasis model

    PMID:31565480

    Open questions at the time
    • Direct biochemical KCTD12-CD271 binding not demonstrated
    • Interaction inferred from phenotype only
  14. 2020 Medium

    Established a region-specific behavioral role whereby dentate gyrus KCTD12 levels bidirectionally control stress vulnerability and granule cell excitability, linked to GABAB signaling.

    Evidence Viral KD/OE in mouse DG, social defeat stress, granule cell electrophysiology, GABAB antagonist pharmacology

    PMID:33285230

    Open questions at the time
    • Single lab
    • Molecular link between KCTD12 level and stress circuitry not fully resolved
  15. 2022 High

    Showed KCTD12, with KCTD8, selectively promotes axonal-terminal GABAB receptor expression and presynaptic excitation in habenular cholinergic neurons, confirmed by rescue in triple-KO mice.

    Evidence Multiple KCTD KO combinations, compartment-specific GABAB immunostaining, presynaptic Ca2+ imaging, glutamate release, rescue overexpression

    PMID:35017224

    Open questions at the time
    • Mechanism of compartment-specific (axonal vs somatic) trafficking not defined
    • Functional redundancy partition between KCTD8 and KCTD12 unresolved
  16. 2025 Low

    Proposed a ferroptosis-related axis in which MSL1 represses KCTD12, which in turn regulates SLC7A11-dependent redox balance in colon cancer.

    Evidence Knockdown/overexpression in HCT116 and SW480 cells with Erastin-induced ferroptosis and redox marker readouts

    PMID:40221412

    Open questions at the time
    • Direct molecular mechanism of MSL1-KCTD12 regulation not biochemically characterized
    • How KCTD12 regulates SLC7A11 not defined
    • Single lab

Open questions

Synthesis pass · forward-looking unresolved questions
  • How KCTD12's two functional domains structurally couple GABAB2 binding to Gβγ-dependent kinetic control, and whether its neuronal auxiliary-subunit role and its cytoplasmic cell-cycle/cancer functions involve distinct conformations or partners, remain unresolved.
  • No high-resolution structure of the KCTD12-GABAB receptor complex
  • Mechanistic unification of neuronal and oncogenic roles lacking
  • Direct partner interfaces (CDK1, CD271) unmapped

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 3 GO:0060089 molecular transducer activity 2
Localization
GO:0005886 plasma membrane 2 GO:0005783 endoplasmic reticulum 1
Pathway
R-HSA-112316 Neuronal System 4 R-HSA-162582 Signal Transduction 2 R-HSA-1640170 Cell Cycle 2
Partners
AURKACDC25BCDK1GABBR2KCTD8ULK2
Complex memberships
GABAB receptor complex

Evidence

Reading pass · 16 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2013 KCTD12 associates with GABAB receptors while they reside in the endoplasmic reticulum (before plasma membrane trafficking), remains associated during receptor activity and internalization, and reduces constitutive receptor internalization, thereby increasing the magnitude of GABAB receptor signaling at the cell surface. Knockdown or knockout of KCTD12 in cultured hippocampal neurons reduces the magnitude of GABAB receptor-mediated K+ current response. Bimolecular fluorescence complementation, metabolic labeling, glycosylation experiments, immunoprecipitation, bioluminescence resonance energy transfer, hippocampal neuron electrophysiology with KO/knockdown The Journal of biological chemistry High 23843457
2013 The N-terminal BTB/POZ domain of KCTD12 (KCTD12BTB) binds the C-terminal region of GABAB2 with low-micromolar affinity; both the BTB and C-terminal H1 domains independently form tetramers; the two domains bind each other, suggesting a compact structure with interacting structured domains joined by a disordered region. CD spectroscopy, binding assays, size-exclusion chromatography, computational secondary structure prediction Journal of molecular recognition : JMR Medium 23996491
2014 KCTD12-induced fast desensitization of GABAB receptor-activated K+ currents is regulated by PKA-dependent phosphorylation of serine-892 on GABAB2: serine-892 phosphorylation rearranges KCTD12 at the receptor and slows KCTD12-induced desensitization. PKA activation in hippocampal neurons slows fast desensitization, and this regulation is absent in KCTD12 knockout mice or S892A knock-in mice. Tonic S892 phosphorylation is itself promoted by assembly of receptors with KCTD12, creating a cross-regulatory loop. Heterologous cell electrophysiology, hippocampal neuron recordings, KCTD12 KO mice, S892A knock-in mice, PKA pharmacology Biochemical pharmacology High 25065880
2015 Loss of KCTD12 (Kctd12−/− mice) increases intrinsic excitability of hippocampal pyramidal neurons and alters emotionality and fear learning, establishing a direct role for KCTD12 in modulating neuronal excitability. Electrophysiological recordings from hippocampal slices of Kctd12−/− and Kctd12+/− mice, behavioral assays Translational psychiatry Medium 25689571
2017 KCTD12 interacts with CDK1 (identified by co-immunoprecipitation and mass spectrometry), activates CDK1 and Aurora kinase A to facilitate G2/M transition. CDC25B silencing abrogates the effects of KCTD12 on CDK1 phosphorylation and cell proliferation. Aurora A phosphorylates KCTD12 at serine 243, creating a positive feedback loop. Co-immunoprecipitation, mass spectrometry, CDC25B siRNA knockdown, phosphorylation assays, cell cycle analysis, xenograft tumor models Oncogene Medium 28869606
2017 KCTD12 desensitization of GABAB receptor-mediated K+ currents is absent in KCTD12-deficient mice in cholecystokinin-expressing interneurons (CCK-INs) in the rat/mouse hippocampus, demonstrating that KCTD12 is required for the desensitization of GABABR-mediated currents in these interneurons. Whole-cell recordings from CCK-INs in KCTD12-deficient mice, immunoelectron microscopy Cerebral cortex High 27073217
2017 Human KCTD12 co-expression accelerates both activation and desensitization kinetics of GABAB receptor-mediated GIRK currents, and enhances the potentiating effects of the positive allosteric modulator CGP7930 on GABAB receptor activation and desensitization. Automated whole-cell electrophysiology in heterologous expression system with human KCTD12, KCTD12 KO mice (in vivo pharmacology) Pharmacology research & perspectives Medium 28713569
2016 KCTD12 suppresses colorectal cancer cell stemness markers (CD44, CD133, CD29) by inhibiting the ERK pathway; ERK1/2 inhibitor U0126 abolishes the increase in stemness markers induced by KCTD12 downregulation, placing KCTD12 upstream of ERK in this pathway. siRNA knockdown, ectopic overexpression, colony/spheroid formation, xenograft model, ERK inhibitor epistasis (U0126) Scientific reports Medium 26847701
2019 Disruption of the KCTD12-CDK1 protein interaction by adefovir dipivoxil induces G2 phase cell cycle arrest and inhibits colon cancer cell proliferation, demonstrating that the KCTD12-CDK1 interaction is functionally necessary for CDK1 activation in this context. Drug screening of FDA-approved library, co-immunoprecipitation to measure interaction disruption, cell cycle analysis, in vitro and xenograft proliferation assays Cancer letters Medium 30872078
2019 Lithium increases KCTD12 expression via inhibition of GSK-3, which leads to CREB-mediated KCTD12 promoter activation. Conversely, GADL1 overexpression enhances GSK-3 activation and inhibits KCTD12 expression, identifying GSK-3 as a regulator of KCTD12 transcription. GSK-3 inhibition in SH-SY5Y cells, KCTD12 promoter reporter assays, GADL1 overexpression, lithium treatment Scientific reports Medium 31311980
2019 KCTD12 interacts with CD271 (p75NTR), and loss of KCTD12 enhances melanoma cell stemness transformation via this interaction. KCTD12 knockout cell lines, in vitro stemness assays, in vivo metastasis model Cancer biology & medicine Low 31565480
2018 KIT knockdown in GIST T1 cells upregulates KCTD12 (pfetin) at both mRNA and protein levels, and KCTD12 knockdown accelerates GIST cell growth, establishing that KIT negatively regulates KCTD12 expression and that KCTD12 functions as a tumor suppressor in GISTs. siRNA KIT knockdown, KCTD12 knockdown, cell proliferation assays in GIST T1 cells, qPCR and Western blot Oncotarget Medium 29930747
2022 KCTD8 and KCTD12 facilitate expression of GABAB receptors specifically in axonal terminals (but not somata) of habenula cholinergic neurons, contributing to presynaptic GABAB-mediated excitation (potentiation of glutamate release and Ca2+ entry). Overexpression of either KCTD8 or KCTD12 in KCTD8/12/16 triple KO mice rescued axonal GABAB expression and presynaptic excitation. Multiple KCTD KO mouse lines (single, double, triple), axonal/somatic GABAB immunostaining, presynaptic Ca2+ imaging, glutamate release measurement, KCTD rescue overexpression The Journal of neuroscience High 35017224
2014 In zebrafish, Kctd12 negatively regulates the kinase Ulk2 via a proline-serine rich domain interaction; Ulk2 positively regulates habenular dendritogenesis, and loss of Kctd12 results in increased dendritic branching/elaboration and decreased anxiety-like behavior. Zebrafish loss-of-function, protein interaction domain mapping (Ulk2 proline-serine rich domain), morphological dendritic analysis, behavioral assays PloS one Medium 25329151
2020 Overexpression of Kctd12 in the dentate gyrus (DG) increases vulnerability to social stress and reduces granule cell excitability, while knockdown of Kctd12 in DG prevents social avoidance and stimulates neuronal activity that contributes to antidepressant-like effects of fluoxetine. GABAB receptor antagonist CGP35348 suppresses stress-induced KCTD12 upregulation and improves behavioral responses. Viral-mediated overexpression and knockdown in mouse DG, chronic social defeat stress model, electrophysiology of DG granule cells, pharmacology with GABABR antagonist Pharmacological research Medium 33285230
2025 MSL1 negatively regulates KCTD12 expression, and KCTD12 in turn regulates SLC7A11 (xCT). In colon cancer cells, Erastin-induced ferroptosis suppresses MSL1, leading to KCTD12 upregulation and consequent modulation of SLC7A11-dependent ROS, GSH, and MDA levels. Biochemical assays, knockdown and overexpression studies in HCT116 and SW480 cells, ferroptosis induction with Erastin Cell death & disease Low 40221412

Source papers

Stage 0 corpus · 24 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2017 KCTD12 promotes tumorigenesis by facilitating CDC25B/CDK1/Aurora A-dependent G2/M transition. Oncogene 57 28869606
2015 Altered emotionality and neuronal excitability in mice lacking KCTD12, an auxiliary subunit of GABAB receptors associated with mood disorders. Translational psychiatry 43 25689571
2013 Up-regulation of GABA(B) receptor signaling by constitutive assembly with the K+ channel tetramerization domain-containing protein 12 (KCTD12). The Journal of biological chemistry 36 23843457
2016 KCTD12 Regulates Colorectal Cancer Cell Stemness through the ERK Pathway. Scientific reports 34 26847701
2019 Adefovir dipivoxil sensitizes colon cancer cells to vemurafenib by disrupting the KCTD12-CDK1 interaction. Cancer letters 32 30872078
2017 KCTD12 Auxiliary Proteins Modulate Kinetics of GABAB Receptor-Mediated Inhibition in Cholecystokinin-Containing Interneurons. Cerebral cortex (New York, N.Y. : 1991) 32 27073217
2014 GABAB receptor phosphorylation regulates KCTD12-induced K⁺ current desensitization. Biochemical pharmacology 28 25065880
2013 A biophysical characterization of the folded domains of KCTD12: insights into interaction with the GABAB2 receptor. Journal of molecular recognition : JMR 28 23996491
2012 Resequencing of the auxiliary GABA(B) receptor subunit gene KCTD12 in chronic tinnitus. Frontiers in systems neuroscience 25 22654739
2018 Contribution of KCTD12 to esophageal squamous cell carcinoma. BMC cancer 23 30157793
2019 Genome-wide association analysis reveals KCTD12 and miR-383-binding genes in the background of rumination. Translational psychiatry 22 30886212
2020 KCTD12 promotes G1/S transition of breast cancer cell through activating the AKT/FOXO1 signaling. Journal of clinical laboratory analysis 18 32207860
2016 Lentiviral-mediated overexpression of KCTD12 inhibits the proliferation of human uveal melanoma OCM-1 cells. Oncology reports 13 28000887
2022 KCTD8 and KCTD12 Facilitate Axonal Expression of GABAB Receptors in Habenula Cholinergic Neurons. The Journal of neuroscience : the official journal of the Society for Neuroscience 12 35017224
2019 Downregulation of KCTD12 contributes to melanoma stemness by modulating CD271. Cancer biology & medicine 12 31565480
2017 KCTD12 modulation of GABA(B) receptor function. Pharmacology research & perspectives 11 28713569
2014 The Drosophila Kctd-family homologue Kctd12-like modulates male aggression and mating behaviour. The European journal of neuroscience 10 24830553
2020 The effects of Kctd12, an auxiliary subunit of GABAB receptor in dentate gyrus on behavioral response to chronic social defeat stress in mice. Pharmacological research 9 33285230
2022 LINC00365 inhibited lung adenocarcinoma progression and glycolysis via sponging miR-429/KCTD12 axis. Environmental toxicology 8 35426242
2019 Lithium and GADL1 regulate glycogen synthase kinase-3 activity to modulate KCTD12 expression. Scientific reports 8 31311980
2025 Male-specific lethal 1 (MSL1) promotes Erastin-induced ferroptosis in colon cancer cells by regulating the KCTD12-SLC7A11 axis. Cell death & disease 5 40221412
2018 KCTD12 is negatively regulated by Kit in gastrointestinal stromal tumors. Oncotarget 5 29930747
2014 Kctd12 and Ulk2 partner to regulate dendritogenesis and behavior in the habenular nuclei. PloS one 4 25329151
2026 RETRACTION: KCTD12 Promotes G1/S Transition of Breast Cancer Cell through Activating the AKT/FOXO1 Signaling. Journal of clinical laboratory analysis 0 41944200

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