Affinage

KCTD12

BTB/POZ domain-containing protein KCTD12 · UniProt Q96CX2

Length
325 aa
Mass
35.7 kDa
Annotated
2026-04-28
24 papers in source corpus 15 papers cited in narrative 15 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

KCTD12 is an auxiliary subunit of GABAB receptors that shapes receptor trafficking, signaling kinetics, and neuronal excitability, while also functioning in cell cycle regulation independently of its neuronal role. Through its N-terminal BTB/POZ domain, KCTD12 assembles with GABAB2 in the endoplasmic reticulum and remains associated through surface trafficking and internalization; it reduces constitutive receptor internalization to increase surface GABAB signaling, accelerates GIRK channel activation and desensitization kinetics, and is cross-regulated by PKA-dependent phosphorylation of GABAB2-S892 (PMID:23843457, PMID:25065880, PMID:23996491, PMID:28713569). Loss of KCTD12 abolishes GABAB-mediated desensitization in CCK interneurons, increases pyramidal neuron excitability and fear learning, and reduces axonal GABAB expression and presynaptic excitation in habenula neurons (PMID:27073217, PMID:25689571, PMID:35017224). In non-neuronal contexts, KCTD12 interacts with CDK1 and promotes G2/M cell cycle progression through CDC25B-dependent CDK1 activation and a positive feedback loop involving Aurora A phosphorylation of KCTD12-S243 (PMID:28869606, PMID:30872078).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2013 High

    Establishing how KCTD12 assembles with GABAB receptors and controls receptor surface availability resolved a key question about how auxiliary subunits regulate GABAB signaling magnitude.

    Evidence Bimolecular fluorescence complementation, metabolic labeling, glycosylation assays, BRET, and electrophysiology in hippocampal neurons with KCTD12 KO/KD

    PMID:23843457

    Open questions at the time
    • Structural basis of KCTD12-mediated reduction of constitutive internalization unknown
    • Whether KCTD12 directly contacts endocytic machinery or acts indirectly not resolved
  2. 2013 High

    Biophysical characterization of KCTD12 domain architecture showed that both BTB and H1 domains independently tetramerize and that the BTB domain directly binds GABAB2 C-terminus with low micromolar affinity, establishing the structural basis of the interaction.

    Evidence CD spectroscopy, analytical ultracentrifugation/SEC, ITC and fluorescence binding assays with recombinant domains

    PMID:23996491

    Open questions at the time
    • No high-resolution structure of the KCTD12–GABAB2 complex
    • Stoichiometry of KCTD12 tetramers within the full receptor complex not fully defined
  3. 2014 High

    Demonstrating that PKA-dependent phosphorylation of GABAB2-S892 rearranges KCTD12 at the receptor complex and slows desensitization revealed a cross-regulatory mechanism tuning GABAB kinetics, validated by S892A knock-in mice.

    Evidence Heterologous cell expression, hippocampal neuron electrophysiology, pharmacology, KCTD12 KO mice, S892A knock-in mice

    PMID:25065880

    Open questions at the time
    • Nature of the S892 phosphorylation-induced structural rearrangement at KCTD12 is unknown
    • Whether other kinases besides PKA regulate this rearrangement not tested
  4. 2014 Medium

    Identification of Ulk2 as a KCTD12 interactor in zebrafish habenula established a non-GABAB function for KCTD12 in restricting dendritic branching, raising the question of whether this mechanism is conserved in mammals.

    Evidence Zebrafish genetic loss-of-function, domain interaction mapping, morphological imaging

    PMID:25329151

    Open questions at the time
    • Mammalian replication of KCTD12–Ulk2 interaction not established
    • Whether this interaction occurs independently of GABAB receptors unclear
    • Direct binding stoichiometry and affinity not measured
  5. 2015 High

    Showing that KCTD12 KO mice have increased hippocampal pyramidal neuron excitability and enhanced fear learning connected the auxiliary subunit to circuit-level excitability control and behavior.

    Evidence Electrophysiological recordings from hippocampal slices of KCTD12 KO mice, behavioral assays

    PMID:25689571

    Open questions at the time
    • Which specific GABAB-mediated conductances account for the excitability change not dissected
    • Contribution of developmental compensation in KO not excluded
  6. 2017 High

    Cell-type resolution analysis in CCK interneurons demonstrated that KCTD12 is necessary and sufficient for GABAB-mediated IPSC desensitization in these neurons, confirming its role as a desensitization switch in defined interneuron subtypes.

    Evidence Immunoelectron microscopy, whole-cell electrophysiology in hippocampal slices, KCTD12 KO mice

    PMID:27073217

    Open questions at the time
    • Whether other KCTD family members compensate in non-CCK interneurons not fully explored
    • Mechanism by which KCTD12 interferes with Gβγ–GIRK coupling at the molecular level not resolved
  7. 2017 Medium

    Discovery that KCTD12 interacts with CDK1 and promotes G2/M progression through CDC25B and Aurora A phosphorylation of KCTD12-S243 revealed a cell cycle regulatory function entirely distinct from its GABAB role.

    Evidence Co-IP/mass spectrometry, siRNA epistasis, phosphorylation assays, cell cycle analysis, xenograft model

    PMID:28869606

    Open questions at the time
    • Whether KCTD12 acts as a scaffold or allosteric activator of CDK1 is unclear
    • Structural basis of CDK1–KCTD12 interaction unknown
    • Physiological relevance outside cancer cell lines not established
  8. 2019 Medium

    Pharmacological disruption of the KCTD12–CDK1 interaction by adefovir dipivoxil causing G2 arrest validated this interaction as functionally required for CDK1 activation and suggested therapeutic targetability.

    Evidence FDA-approved drug library screen, Co-IP disruption, cell cycle analysis, xenograft model

    PMID:30872078

    Open questions at the time
    • Selectivity of adefovir dipivoxil for KCTD12–CDK1 versus other targets not fully established
    • In vivo pharmacokinetic relevance of drug doses used unclear
  9. 2022 High

    Demonstrating that KCTD8/12 facilitate axonal GABAB expression and presynaptic excitatory signaling in habenula cholinergic neurons, with single-gene rescue, established a trafficking role for KCTD12 in polarized neuronal compartments beyond the somatodendritic domain.

    Evidence KCTD triple/double KO mouse lines, Ca²⁺ imaging, glutamate release assays, AAV-mediated rescue

    PMID:35017224

    Open questions at the time
    • Mechanism by which KCTD12 promotes axonal versus dendritic GABAB targeting unknown
    • Whether KCTD12 directly participates in axonal transport or simply stabilizes receptors at axonal membranes not resolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • A high-resolution structure of the KCTD12–GABAB receptor complex, the molecular mechanism by which KCTD12 promotes axonal receptor targeting, and the physiological significance of KCTD12's cell cycle role in non-transformed tissues remain unresolved.
  • No atomic-resolution structure of KCTD12 bound to GABAB receptor
  • Mechanism of axonal GABAB targeting by KCTD12 not determined
  • Whether KCTD12–CDK1 interaction operates in normal dividing cells unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 4 GO:0060090 molecular adaptor activity 2
Localization
GO:0005886 plasma membrane 2 GO:0005783 endoplasmic reticulum 1
Pathway
R-HSA-112316 Neuronal System 6 R-HSA-162582 Signal Transduction 3 R-HSA-1640170 Cell Cycle 2
Partners
AURKACDC25BCDK1GABBR2KCTD8ULK2
Complex memberships
GABAB receptor complex

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2013 KCTD12 assembles with GABAB receptors in the endoplasmic reticulum and remains associated through receptor activity and internalization; KCTD12 reduces constitutive receptor internalization, thereby increasing the magnitude of GABAB receptor signaling at the neuronal plasma membrane. Knockout or knockdown of KCTD12 in hippocampal neurons reduces GABAB receptor-mediated K+ current response. Bimolecular fluorescence complementation, metabolic labeling, glycosylation assays, immunoprecipitation, bioluminescence resonance energy transfer (BRET), electrophysiology in hippocampal neurons The Journal of biological chemistry High 23843457
2014 KCTD12-induced fast desensitization of GABAB receptor-mediated K+ currents is regulated by PKA-dependent phosphorylation of serine-892 on GABAB2: serine-892 phosphorylation rearranges KCTD12 at the receptor complex and slows KCTD12-induced desensitization. Conversely, KCTD12 assembly promotes tonic serine-892 phosphorylation, creating a cross-regulatory loop. This was abolished in KCTD12 KO and S892A knock-in mice. Heterologous cell expression, hippocampal neuron electrophysiology, PKA pharmacology, KCTD12 KO mice, S892A knock-in mice Biochemical pharmacology High 25065880
2013 The N-terminal BTB/POZ domain (KCTD12BTB) and C-terminal domain (KCTD12H1) of KCTD12 each independently form tetramers and bind each other with good affinity. KCTD12BTB binds the C-terminal region of GABAB2 with low micromolar affinity, and a GABAB2-derived peptide binds KCTD12BTB with very high affinity. CD spectroscopy, analytical ultracentrifugation/SEC, binding assays (ITC/fluorescence), recombinant domain expression Journal of molecular recognition : JMR High 23996491
2017 KCTD12 interacts with CDK1 (identified by immunoprecipitation and mass spectrometry) and activates CDK1 and Aurora kinase A to facilitate G2/M transition. CDC25B silencing abrogates KCTD12 effects on CDK1 phosphorylation and cell proliferation. Aurora A phosphorylates KCTD12 at serine 243, creating a positive feedback loop. Immunoprecipitation, mass spectrometry, Co-IP, siRNA knockdown, phosphorylation assays, cell cycle analysis, xenograft tumor model Oncogene Medium 28869606
2017 KCTD12 auxiliary proteins are highly expressed in CCK-expressing interneurons and mediate desensitization of GABAB receptor-mediated inhibitory postsynaptic currents; desensitization was absent in KCTD12-deficient mice, demonstrating KCTD12 controls both kinetics and desensitization of GABABR-mediated currents in CCK interneurons. Immunoelectron microscopy, whole-cell electrophysiology in hippocampal slices, KCTD12 knockout mice Cerebral cortex High 27073217
2015 Loss of KCTD12 (KO mice) increases intrinsic excitability of hippocampal pyramidal neurons, demonstrating that KCTD12 as a GABAB receptor auxiliary subunit regulates neuronal excitability in vivo. KCTD12-deficient mice also show increased fear learning. Electrophysiological recordings from hippocampal slices of KCTD12 KO mice, behavioral assays Translational psychiatry High 25689571
2022 KCTD8 and KCTD12 facilitate axonal expression of GABAB receptors in habenula cholinergic neurons and contribute to presynaptic GABAB-mediated excitation (potentiation of glutamate release and Ca2+ entry); knockout of KCTD8/12 reduced axonal GABAB expression and presynaptic excitation, and overexpression of either KCTD8 or KCTD12 rescued these deficits. KCTD triple/double KO mouse lines, Ca2+ imaging, glutamate release assays, immunofluorescence, behavioral assays, AAV-mediated overexpression rescue The Journal of neuroscience High 35017224
2014 In zebrafish habenular neurons, Kctd12 negatively regulates the kinase Ulk2 via a proline-serine rich domain interaction, restraining Ulk2-driven dendritic branching and elaboration. Loss of Kctd12 results in increased dendritic branching and decreased anxiety behavior. Zebrafish genetic loss-of-function, protein interaction domain mapping, morphological imaging, behavioral assays PloS one Medium 25329151
2017 Human KCTD12 co-expression accelerates both activation and desensitization kinetics of GABAB receptor-mediated GIRK channel currents and enhances the potentiating effects of the positive allosteric modulator CGP7930 on GABABR. KCTD12 KO mice show reduced seizure susceptibility and altered ethanol consumption. Automated electrophysiology (QPatch), heterologous co-expression, KCTD12 KO mice, behavioral pharmacology Pharmacology research & perspectives Medium 28713569
2019 The KCTD12-CDK1 protein-protein interaction is required for CDK1 activation; disruption of this interaction by adefovir dipivoxil (identified by screening an FDA-approved drug library) induces G2 phase arrest and inhibits cancer cell proliferation. Drug library screen, Co-IP disruption assay, cell cycle analysis, proliferation assays, xenograft tumor model Cancer letters Medium 30872078
2018 KIT signaling negatively regulates KCTD12 expression in GIST cells; KIT knockdown upregulates KCTD12 at both mRNA and protein level, and KCTD12 knockdown accelerates GIST cell growth, establishing KCTD12 as a downstream tumor suppressor in KIT signaling. KIT siRNA knockdown in GIST T1 cells, Western blot, qPCR, cell growth assays Oncotarget Medium 29930747
2019 Lithium induces KCTD12 expression via inhibition of GSK-3, which leads to CREB-mediated KCTD12 promoter activation. GADL1 overexpression enhances GSK-3 activity and suppresses KCTD12 expression, demonstrating that GSK-3/CREB signaling is an upstream regulator of KCTD12 transcription. Pharmacological GSK-3 inhibition, GADL1 overexpression, KCTD12 promoter reporter assay, Western blot in SH-SY5Y cells Scientific reports Medium 31311980
2020 Kctd12 overexpression in the dentate gyrus increases vulnerability to social stress and regulates excitability of granule cells; Kctd12 knockdown in dentate gyrus prevents social avoidance and stimulates neuronal activity, contributing to antidepressant-like effects of fluoxetine. GABAB receptor antagonist CGP35348 reduced stress-induced behavior and suppressed excess Kctd12 expression. AAV-mediated Kctd12 overexpression/knockdown in mouse dentate gyrus, electrophysiology (granule cell excitability), behavioral assays (CSDS model), pharmacological manipulation Pharmacological research Medium 33285230
2025 MSL1 negatively regulates KCTD12 expression; in colon cancer cells, Erastin (ferroptosis inducer) suppresses MSL1, leading to KCTD12 upregulation, which in turn suppresses SLC7A11 and promotes ferroptosis. The MSL1-KCTD12-SLC7A11 axis regulates ROS, GSH, and MDA levels in ferroptosis. Biochemical assays, siRNA knockdown, overexpression studies, ROS/GSH/MDA measurement, ferroptosis assays Cell death & disease Medium 40221412
2019 KCTD12 knockdown in melanoma cells enhances stemness markers including CD271, and KCTD12 interacts with CD271; this interaction regulates melanoma cell stemness transformation and metastatic capacity in vitro and in vivo. KCTD12 KO A375 cells (CRISPR), spheroid formation, mouse metastatic model, Western blot for CD271 Cancer biology & medicine Low 31565480

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 56 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) 31 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 21 30886212
2020 KCTD12 promotes G1/S transition of breast cancer cell through activating the AKT/FOXO1 signaling. Journal of clinical laboratory analysis 17 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