Affinage

GNB4

Guanine nucleotide-binding protein subunit beta-4 · UniProt Q9HAV0

Round 2 corrected
Length
340 aa
Mass
37.6 kDa
Annotated
2026-04-28
41 papers in source corpus 12 papers cited in narrative 12 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

GNB4 encodes guanine nucleotide-binding protein subunit beta-4 (Gβ4), a WD40 repeat-containing scaffold that forms obligate Gβγ dimers and participates in heterotrimeric G protein signaling with combinatorial selectivity determined by specific Gαi–Gβ pairings at GPCRs such as α2-adrenergic and bradykinin receptors (PMID:16371464, PMID:23434117). Missense mutations clustering within the WD40 domain impair GPCR signaling and cause autosomal dominant Charcot-Marie-Tooth neuropathy with mixed demyelinating and axonal features (PMID:23434117, PMID:34071515, PMID:41164122). In cancer contexts, GNB4 expression is upregulated by NF-κB–TET1-mediated promoter demethylation to activate Hippo-YAP1 oncogenic signaling in gastric cancer, suppresses cGAS-STING-dependent pyroptosis in glioma, and interacts with circRREB1 to drive Erk1/2 signaling in breast cancer (PMID:37016382, PMID:38814382, PMID:38617926). GNB4 also functions as a negative regulator of osteoblast differentiation downstream of miR-133b (PMID:33687637).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 1999 Medium

    Establishing that GNB4 belongs to the Gβ gene family encoding conserved WD40-repeat scaffolds provided the foundational framework for understanding its role in heterotrimeric G protein signaling.

    Evidence Genomic sequence and phylogenetic analysis of the G protein subunit gene families

    PMID:10644457

    Open questions at the time
    • No isoform-specific functional data for Gβ4 itself
    • Expression pattern of GNB4 across tissues not determined
  2. 2002 High

    Demonstrating that Gβ subunits can be phosphorylated at His-266 by NDPK B to relay high-energy phosphate to GDP revealed a non-canonical, GPCR-independent mechanism of G protein activation potentially applicable to Gβ4.

    Evidence Biochemical enrichment, co-immunoprecipitation, thiophosphorylation with radiolabeled GTPγS, and peptide sequencing on purified Gβγ; primarily shown for Gβ1

    PMID:12486123

    Open questions at the time
    • Direct demonstration on Gβ4 specifically was not performed
    • Physiological relevance of His-266 phosphorylation in vivo remains unresolved
  3. 2005 High

    Live-cell FRET experiments revealed that Gβ4 couples with Gαi1, Gαi2, or Gαi3 to form functionally distinct heterotrimers at α2-adrenergic receptors, establishing that GPCR signaling specificity arises from combinatorial Gα–Gβ pairing rather than individual subunit identity.

    Evidence FRET between Gαi-YFP and CFP-Gβ chimeras in HeLa cells with siRNA knockdown of receptor subtypes

    PMID:16371464

    Open questions at the time
    • Whether combinatorial selectivity extends to other GPCR families was not tested
    • Downstream effector specificity of Gβ4-containing heterotrimers not characterized
  4. 2013 High

    The discovery that GNB4 missense mutations (p.Gly53Asp, p.Lys89Glu) cause dominant intermediate CMT neuropathy and impair bradykinin-induced GPCR signaling established GNB4 as a disease gene and linked its WD40-mediated signaling function to peripheral nerve biology.

    Evidence Genome-wide linkage, exome sequencing, familial segregation, in vitro GPCR signaling assays with wild-type vs. mutant Gβ4, immunohistochemistry on sural nerve

    PMID:23434117

    Open questions at the time
    • Mechanism by which impaired Gβ4 signaling leads to neuropathy (axonal vs. Schwann cell-autonomous) not resolved
    • Crystal structure of mutant Gβ4 not available
  5. 2016 Medium

    Identification of a de novo GNB4 mutation (p.Lys57Glu) in severe CMT confirmed that pathogenic GNB4 variants arise independently and are not merely inherited segregating variants.

    Evidence Whole exome sequencing with Sanger validation in a family trio

    PMID:27908631

    Open questions at the time
    • No functional assay performed for this specific variant
    • Genotype-phenotype correlations for disease severity remain poorly defined
  6. 2017 Medium

    A novel pathogenic variant (p.Gln220Arg) in exon 8 placed the disease-associated mutation spectrum firmly within the WD40 repeat domain, reinforcing the structural importance of this domain for Gβ4 function.

    Evidence Exome sequencing with familial segregation; absence in 502 controls and ExAC

    PMID:28642160

    Open questions at the time
    • No in vitro functional validation of p.Gln220Arg
    • Structure-function relationship of specific WD40 blades to signaling not dissected
  7. 2021 Medium

    Demonstrating that certain GNB4 mutations produce demyelinating rather than purely intermediate neuropathy, with sural nerve histopathology showing onion bulb formation, resolved that the disease mechanism involves a prominent Schwann cell-autonomous demyelinating component.

    Evidence Whole exome sequencing, nerve conduction studies, sural nerve biopsy with histopathology, and lower extremity MRI

    PMID:34071515

    Open questions at the time
    • Mechanism by which Gβ4 loss-of-function specifically causes demyelination not elucidated
    • Animal model recapitulating GNB4-CMT not established
  8. 2021 Medium

    Identifying GNB4 as a direct target of miR-133b whose overexpression reverses osteoblast differentiation revealed a non-neuronal, non-canonical role for Gβ4 as a negative regulator of osteogenic commitment.

    Evidence miRNA target validation, gain/loss-of-function experiments, Western blot and qRT-PCR for differentiation markers in hFOB 1.19 cells

    PMID:33687637

    Open questions at the time
    • Downstream signaling pathway by which GNB4 suppresses osteoblast differentiation unknown
    • Single cell line, no in vivo bone formation data
  9. 2023 High

    Tracing GNB4 upregulation to H. pylori-driven NF-κB–TET1 promoter demethylation and its downstream activation of the Hippo-YAP1 pathway established a complete mechanistic axis through which GNB4 drives gastric cancer oncogenesis.

    Evidence Methylation-specific PCR, pyrosequencing, ChIP of TET1 on GNB4 promoter, Co-IP, functional assays (CCK-8, transwell, colony formation), xenograft mouse model

    PMID:37016382

    Open questions at the time
    • How Gβ4 protein biochemically activates Hippo-YAP1 (direct interaction or intermediate effectors) not resolved
    • Whether this pathway operates in other H. pylori-associated malignancies untested
  10. 2024 Medium

    Showing that GNB4 silencing activates cGAS-STING-mediated pyroptosis in glioma, reversible by STING inhibition, placed Gβ4 as an upstream suppressor of innate immune sensing in a second cancer type.

    Evidence siRNA knockdown, CCK-8, transwell, Western blot for pyroptosis markers, ELISA, cGAS-STING inhibitor rescue in glioma cell lines

    PMID:38814382

    Open questions at the time
    • Biochemical mechanism linking Gβ4 to cGAS-STING suppression unknown
    • No in vivo validation
    • Single study, not independently confirmed
  11. 2024 Medium

    Discovery that circRREB1 physically binds GNB4 protein to activate Erk1/2 signaling in breast cancer revealed a non-canonical RNA-protein interaction mode for Gβ4 distinct from classical Gβγ heterotrimer function.

    Evidence RNA pull-down with mass spectrometry, RIP, FISH, rescue experiments, in vivo tumor models in breast cancer cells

    PMID:38617926

    Open questions at the time
    • Structural basis for circRREB1-Gβ4 interaction undetermined
    • Whether circRNA binding competes with Gγ dimerization unknown
    • Single study
  12. 2025 Medium

    3D structural mapping of all known pathogenic GNB4 variants demonstrated spatial clustering on the Gβ4 WD40 propeller, suggesting a shared structural mechanism of disruption at a functional interface.

    Evidence Whole exome sequencing, electrophysiology, ACMG reclassification, and 3D protein structural mapping

    PMID:41164122

    Open questions at the time
    • No experimental structure of Gβ4 bound to Gα or GPCR with mutants modeled
    • Functional consequence of clustering (e.g., loss of Gα binding surface) not biochemically tested

Open questions

Synthesis pass · forward-looking unresolved questions
  • The biochemical mechanism by which Gβ4 WD40 domain mutations specifically cause peripheral nerve demyelination, and how Gβ4 activates Hippo-YAP1 or suppresses cGAS-STING in cancer, remain major unresolved questions.
  • No Gβ4-specific crystal or cryo-EM structure available
  • No animal model recapitulating GNB4-CMT neuropathy
  • Biochemical link between Gβ4 and non-canonical signaling pathways (YAP1, cGAS-STING, Erk1/2 via circRNA) not mechanistically resolved

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 4 GO:0060090 molecular adaptor activity 3
Localization
GO:0005829 cytosol 2 GO:0005886 plasma membrane 2
Pathway
R-HSA-162582 Signal Transduction 5 R-HSA-1643685 Disease 5 R-HSA-168256 Immune System 1
Partners
CGASGNAI1GNAI2GNAI3STING1TET1YAP1
Complex memberships
Heterotrimeric G protein (Gαβγ)

Evidence

Reading pass · 12 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1999 GNB4 (Gβ4) belongs to the G protein β subunit gene family, which encodes WD40 repeat-containing proteins that form obligate dimers with Gγ subunits and serve as scaffolds for heterotrimeric G protein signaling; the family members share conserved domain architecture and genomic organization. Genomic sequence analysis and phylogenetic characterization of the G protein subunit gene families Genomics Medium 10644457
2002 Gβ subunits (including Gβ1 and by extension other Gβ isoforms) can be phosphorylated at His-266 by nucleoside diphosphate kinase B (NDPK B), which forms a complex with Gβγ dimers; this high-energy phosphate transfer from GTP can be relayed to GDP to generate GTP, providing a non-canonical mechanism for G protein activation independent of GPCRs. Biochemical enrichment of Gβ-phosphorylating activity, co-immunoprecipitation, thiophosphorylation with radiolabeled GTPγS, peptide sequencing to identify His-266 in Gβ1; reconstitution with purified Gβγ The Journal of Biological Chemistry High 12486123
2005 Gβ4 (along with Gβ1 and Gβ2) can couple with Gαi1, Gαi2, or Gαi3 to form heterotrimers that are activated by α2-adrenergic receptors; the degree of G protein activation is determined by the specific combination of Gαi and Gβ subunit isoforms rather than by the identity of either subunit alone, establishing combinatorial selectivity in GPCR signaling. FRET between Gαi-YFP and CFP-Gβ chimeras in live HeLa cells; siRNA knockdown of α2-adrenergic receptor subtypes; radiolabeled antagonist binding; RT-PCR Proceedings of the National Academy of Sciences of the United States of America High 16371464
2013 Missense mutations in GNB4 (p.Gly53Asp and p.Lys89Glu) cause dominant intermediate Charcot-Marie-Tooth disease (CMTDIF); Gβ4 is expressed in axons and Schwann cells of peripheral nerves, and both mutant proteins impair bradykinin-induced GPCR signaling that is normally facilitated by wild-type Gβ4, while p.Gly53Asp also causes significantly reduced Gβ4 protein expression in sural nerve. Genome-wide linkage mapping; exome sequencing; Sanger sequencing for segregation; immunohistochemistry on sural nerve biopsy; in vitro GPCR signaling assay (bradykinin-induced signaling) with wild-type vs. mutant Gβ4 American Journal of Human Genetics High 23434117
2016 A de novo GNB4 mutation p.Lys57Glu (not present in parents or unaffected sibling) causes severe CMT neuropathy, further confirming that GNB4 is a causative CMT gene and that de novo mutations in this gene are pathogenic. Whole exome sequencing; Sanger sequencing for segregation analysis in family trio Neuromuscular Disorders Medium 27908631
2017 A novel GNB4 missense variant p.Gln220Arg in exon 8 causes autosomal dominant CMT neuropathy; the affected residue lies in the highly conserved WD40 domain of GNB4, establishing that the WD40 repeat domain is critical for Gβ4 function in peripheral nerves. Exome sequencing; Sanger sequencing for familial segregation; absence confirmed in 502 Japanese controls and ExAC database European Journal of Medical Genetics Medium 28642160
2021 GNB4 mutations (p.Gly77Arg and p.Lys89Glu) cause not only intermediate-type but also demyelinating-type CMT neuropathy; sural nerve biopsy of p.Lys89Glu patients showed severe loss of myelinated axons with onion bulb formation, indicating that specific GNB4 mutations differentially affect the demyelinating vs. axonal disease mechanism. Whole-exome sequencing; nerve conduction studies; sural nerve biopsy with histopathology; lower extremity MRI for muscle fat infiltration Life (Basel) Medium 34071515
2021 GNB4 is a target of miR-133b in osteoblasts; miR-133b overexpression promotes osteoblast viability and differentiation (increased ALP, Runx2, Osterix, OPN expression), and these effects are reversed by GNB4 overexpression, placing GNB4 as a negative regulator of osteoblast differentiation downstream of miR-133b. miRNA target validation; qRT-PCR and Western blot for GNB4 expression; CCK-8 viability assay; flow cytometry apoptosis assay; Western blot for osteoblast differentiation markers; gain- and loss-of-function in hFOB 1.19 cells Biochemical Genetics Medium 33687637
2023 H. pylori infection promotes GNB4 expression in gastric cancer cells via an NF-κB–TET1–GNB4 promoter demethylation axis; elevated GNB4 in turn activates the Hippo-YAP1 pathway to drive oncogenic proliferation, invasion, and metastasis both in vitro and in vivo. Methylation-specific PCR; pyrosequencing; mass spectrometry for methylation; chromatin immunoprecipitation (ChIP) of TET1 on GNB4 promoter; co-immunoprecipitation; CCK-8, EdU, colony formation, transwell assays; xenograft mouse model; Western blot, immunofluorescence, immunohistochemistry; siRNA knockdown and overexpression BMC Medicine High 37016382
2024 GNB4 silencing in glioma cells promotes pyroptosis and inhibits proliferation, migration, and invasion by activating the cGAS-STING pathway; pharmacological inhibition of cGAS-STING reverses the anti-tumor effects of GNB4 silencing and downregulates pyroptosis-related proteins, establishing GNB4 as an upstream suppressor of cGAS-STING-mediated pyroptosis in glioma. siRNA-mediated GNB4 silencing; CCK-8 proliferation assay; wound-healing and transwell migration/invasion assays; Western blot for pyroptosis-related proteins; ELISA for inflammatory factors; cGAS-STING pathway inhibitor rescue experiments Molecular Biotechnology Medium 38814382
2024 CircRREB1 directly interacts with GNB4 protein in breast cancer cells and this interaction activates Erk1/2 signaling, promoting tumor cell proliferation, migration, and invasion; knockdown of circRREB1 phenocopies GNB4 pathway inhibition and rescue experiments confirm the circRREB1-GNB4-Erk1/2 axis. RNA pull-down; mass spectrometry; Western blot; RNA immunoprecipitation (RIP); fluorescence in situ hybridization (FISH); rescue experiments with GNB4 modulation; in vivo tumor models Heliyon Medium 38617926
2025 Pathogenic GNB4 variants associated with CMT cluster spatially on the 3D structure of the GNB4 protein, and GNB4-associated neuropathy presents with mixed axonal and demyelinating features; a novel variant p.Ile80Thr was identified and classified as likely pathogenic. Whole exome sequencing; segregation analysis; neurological and electrophysiological assessment; 3D protein structural mapping of variant positions; literature review and ACMG variant reclassification Neurology: Genetics Medium 41164122

Source papers

Stage 0 corpus · 41 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2002 Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. Proceedings of the National Academy of Sciences of the United States of America 1479 12477932
2015 The BioPlex Network: A Systematic Exploration of the Human Interactome. Cell 1118 26186194
2017 Architecture of the human interactome defines protein communities and disease networks. Nature 1085 28514442
2015 A human interactome in three quantitative dimensions organized by stoichiometries and abundances. Cell 1015 26496610
2003 Complete sequencing and characterization of 21,243 full-length human cDNAs. Nature genetics 754 14702039
2021 Dual proteome-scale networks reveal cell-specific remodeling of the human interactome. Cell 705 33961781
2011 Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium. Briefings in bioinformatics 656 21873635
2003 Glucagon and regulation of glucose metabolism. American journal of physiology. Endocrinology and metabolism 635 12626323
2004 The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome research 438 15489334
2022 OpenCell: Endogenous tagging for the cartography of human cellular organization. Science (New York, N.Y.) 432 35271311
2010 Systematic analysis of human protein complexes identifies chromosome segregation proteins. Science (New York, N.Y.) 421 20360068
2015 Panorama of ancient metazoan macromolecular complexes. Nature 407 26344197
1999 Ggamma13 colocalizes with gustducin in taste receptor cells and mediates IP3 responses to bitter denatonium. Nature neuroscience 278 10570481
2013 Identification of heart rate-associated loci and their effects on cardiac conduction and rhythm disorders. Nature genetics 250 23583979
1999 The G protein subunit gene families. Genomics 224 10644457
2007 hORFeome v3.1: a resource of human open reading frames representing over 10,000 human genes. Genomics 222 17207965
2014 Proximity biotinylation and affinity purification are complementary approaches for the interactome mapping of chromatin-associated protein complexes. Journal of proteomics 215 25281560
2018 An AP-MS- and BioID-compatible MAC-tag enables comprehensive mapping of protein interactions and subcellular localizations. Nature communications 201 29568061
2015 A deep proteomics perspective on CRM1-mediated nuclear export and nucleocytoplasmic partitioning. eLife 198 26673895
2016 Two Distinct Types of E3 Ligases Work in Unison to Regulate Substrate Ubiquitylation. Cell 188 27565346
2013 The protein interaction landscape of the human CMGC kinase group. Cell reports 174 23602568
2007 Integral and associated lysosomal membrane proteins. Traffic (Copenhagen, Denmark) 163 17897319
2020 A High-Density Human Mitochondrial Proximity Interaction Network. Cell metabolism 148 32877691
2013 In-depth proteomic analyses of exosomes isolated from expressed prostatic secretions in urine. Proteomics 138 23533145
2019 Mapping the proximity interaction network of the Rho-family GTPases reveals signalling pathways and regulatory mechanisms. Nature cell biology 137 31871319
2022 Human transcription factor protein interaction networks. Nature communications 123 35140242
2018 Proteome-wide analysis of USP14 substrates revealed its role in hepatosteatosis via stabilization of FASN. Nature communications 123 30425250
2002 Activation of heterotrimeric G proteins by a high energy phosphate transfer via nucleoside diphosphate kinase (NDPK) B and Gbeta subunits. Complex formation of NDPK B with Gbeta gamma dimers and phosphorylation of His-266 IN Gbeta. The Journal of biological chemistry 118 12486123
2005 Gialpha and Gbeta subunits both define selectivity of G protein activation by alpha2-adrenergic receptors. Proceedings of the National Academy of Sciences of the United States of America 113 16371464
2018 Ubiquilin 2 modulates ALS/FTD-linked FUS-RNA complex dynamics and stress granule formation. Proceedings of the National Academy of Sciences of the United States of America 108 30442662
2013 Exome sequencing identifies GNB4 mutations as a cause of dominant intermediate Charcot-Marie-Tooth disease. American journal of human genetics 43 23434117
2023 Helicobacter pylori-induced aberrant demethylation and expression of GNB4 promotes gastric carcinogenesis via the Hippo-YAP1 pathway. BMC medicine 30 37016382
2023 Plasma methylated GNB4 and Riplet as a novel dual-marker panel for the detection of hepatocellular carcinoma. Epigenetics 22 38154055
2017 A novel missense variant (Gln220Arg) of GNB4 encoding guanine nucleotide-binding protein, subunit beta-4 in a Japanese family with autosomal dominant motor and sensory neuropathy. European journal of medical genetics 12 28642160
2016 Confirmation of the GNB4 gene as causal for Charcot-Marie-Tooth disease by a novel de novo mutation in a Czech patient. Neuromuscular disorders : NMD 11 27908631
2024 CircRNA circRREB1 promotes tumorigenesis and progression of breast cancer by activating Erk1/2 signaling through interacting with GNB4. Heliyon 10 38617926
2021 Clinical and Neuroimaging Features in Charcot-Marie-Tooth Patients with GNB4 Mutations. Life (Basel, Switzerland) 10 34071515
2021 MiR-133b Modulates the Osteoblast Differentiation to Prevent Osteoporosis Via Targeting GNB4. Biochemical genetics 8 33687637
2024 GNB4 Silencing Promotes Pyroptosis to Inhibit the Development of Glioma by Activating cGAS-STING Pathway. Molecular biotechnology 6 38814382
2022 Disrupting circ-GNB4 mitigates high glucose-induced human mesangial cells injury by regulating the proliferation, ECM accumulation, inflammation and oxidative stress through circ-GNB4/miR-23c/EGR1 pathway [RETRACTED]. Journal of cardiovascular pharmacology 6 35170486
2025 Novel GNB4 Gene Variant and the Spectrum of GNB4 Variants in Patients With Charcot-Marie-Tooth Disease. Neurology. Genetics 0 41164122