{"gene":"UGCG","run_date":"2026-06-10T10:51:56","timeline":{"discoveries":[{"year":2018,"finding":"UGCG is the key enzyme in sphingolipid metabolism that generates glucosylceramide (GlcCer) de novo, serving as the precursor for all glycosphingolipids; UGCG overexpression correlates with MDR1 expression and influences lipid composition of membranes in multidrug-resistant cells.","method":"Review synthesizing biochemical and cell biology data; UGCG enzymatic function as GlcCer synthase established by prior biochemical work summarized herein","journal":"BMC cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — review paper synthesizing multiple prior experimental studies establishing UGCG enzymatic activity and MDR1 correlation; no single new experiment presented","pmids":["29409484"],"is_preprint":false},{"year":2019,"finding":"UGCG overexpression in breast cancer cells adapts glutamine metabolism under nutrient-poor conditions, increasing glutamine uptake for oxidative stress response (via elevated GSR/GSH) and fueling the TCA cycle to maintain proliferative advantage.","method":"UGCG overexpression in MCF-7 cells; mRNA expression analysis, metabolite measurements (GSH, glutamine), functional metabolic assays","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single lab, multiple metabolic readouts but no reconstitution or epistasis; functional link established by OE with specific metabolic phenotype","pmids":["31666638"],"is_preprint":false},{"year":2020,"finding":"UGCG overexpression in breast cancer cells shifts cellular metabolism from quiescent/aerobic to an energetic phenotype by increasing both glycolysis and oxidative glucose metabolism, and alters sphingolipid composition of ER/mitochondria fractions contributing to increased mitochondrial turnover.","method":"UGCG overexpression in MCF-7 cells; Seahorse metabolic flux assays, lipidomics of ER/mitochondria fractions, mitochondrial mass/turnover markers","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — single lab, two orthogonal methods (metabolic flux + lipidomics with fractionation), defined cellular phenotype","pmids":["32424263"],"is_preprint":false},{"year":2023,"finding":"UGCG drives resistance to lysosomal autophagy inhibition (LAI) by producing glycosphingolipids that promote GM1+ membrane microdomain (GMM) formation in plasma membranes and lysosomes; UGCG inhibition decreases LAI-induced GMMs and augments cell death, while UGCG overexpression confers LAI resistance.","method":"Proteomics, lipidomics, immunoblotting, UGCG inhibition (eliglustat) and overexpression in cancer cell lines; syngeneic tumor and patient-derived xenograft models","journal":"Cancer discovery","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (proteomics, lipidomics, gain- and loss-of-function), replicated in cell lines and in vivo models","pmids":["36331284"],"is_preprint":false},{"year":2023,"finding":"UGCG enzymatic activity can be measured in vitro using deuterated ceramide as acceptor substrate and LC-MS/MS quantitation of deuterated glucosylceramide product; kinetic parameters of UGCG and inhibition by GZ667161 were determined in model cells and human fibroblasts.","method":"In vitro enzyme activity assay with deuterated ceramide substrate; LC-MS/MS quantitation; inhibitor dose-response in cell homogenates","journal":"Glycobiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro enzymatic assay with substrate, kinetic parameter determination, and inhibitor characterization; single lab but rigorous biochemical approach","pmids":["36504340"],"is_preprint":false},{"year":2023,"finding":"UGCG physically interacts with B4GalT5 (beta-1,4-galactosyltransferase 5, which catalyzes lactosylceramide synthesis); this interaction is synergistic, and limiting B4GalT5 expression impairs UGCG's capacity to promote cardiomyocyte hypertrophy. UGCG modulates heart hypertrophy through mitochondrial oxidative stress and ERK signaling activation.","method":"Co-immunoprecipitation identifying UGCG–B4GalT5 interaction; UGCG knockdown and overexpression in cardiomyocytes; B4GalT5 knockdown epistasis; ERK signaling pathway analysis; in vivo pressure overload model","journal":"Cellular & molecular biology letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP for interaction plus genetic epistasis (B4GalT5 KD rescues UGCG OE phenotype), single lab","pmids":["37658291"],"is_preprint":false},{"year":2024,"finding":"UGCG inhibition suppresses pseudorabies virus (PRV) infection by disrupting lysosomal homeostasis (altered lysosomal pH, impaired lysosome-associated proteins), blocking autophagic flux, and preventing LC3-STING complex formation, thereby sustaining STING signaling activation that resists PRV infection.","method":"shRNA knockdown and pharmacological inhibition (eliglustat, ibiglustat) of UGCG; autophagy flux assays (LC3-II conversion), lysosomal pH measurement, STING signaling analysis, LC3-STING co-immunoprecipitation; in vivo efficacy evaluation","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (KD + pharmacological inhibition, lysosomal assays, Co-IP, in vivo), single lab","pmids":["39631580"],"is_preprint":false},{"year":2024,"finding":"UGCG overexpression in HEK293 cells removes intracellular polyplex sequestration in endosomes, improving transfection efficiency; this indicates UGCG activity influences endosomal membrane composition and polyplex trafficking.","method":"UGCG overexpression in HEK293 cells; transfection efficiency assays, VLP production quantitation, endosomal sequestration imaging","journal":"Molecular therapy. Methods & clinical development","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single functional readout (transfection efficiency), mechanistic link to endosomal biology inferred but not deeply characterized","pmids":["38327808"],"is_preprint":false},{"year":2024,"finding":"UGCG promotes chemoresistance and malignant progression of triple-negative breast cancer by amplifying NF-κB and Wnt/β-catenin pathway activation; inhibitors of these pathways diminish UGCG-induced malignant effects.","method":"Gain- and loss-of-function experiments in TNBC cell lines; Western blotting, qRT-PCR for NF-κB and Wnt/β-catenin pathway components; pathway inhibitor rescue experiments","journal":"Translational oncology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — gain/loss-of-function with pathway inhibitor rescue across two pathways, single lab, no reconstitution","pmids":["39674092"],"is_preprint":false},{"year":2025,"finding":"Miglustat ameliorates isoproterenol-induced cardiac fibrosis by targeting UGCG; UGCG knockdown in primary cardiac fibroblasts suppresses ERK, STAT3, Akt, and GSK3β signaling activated by β-adrenergic receptor overactivation.","method":"UGCG siRNA knockdown in primary cardiac fibroblasts; in vivo isoproterenol cardiac fibrosis model with miglustat treatment; Western blotting for signaling pathways; GEO data validation","journal":"Molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function in primary cells plus in vivo pharmacological inhibition, multiple signaling pathway readouts, single lab","pmids":["39934657"],"is_preprint":false},{"year":2025,"finding":"In liver sinusoidal endothelial cells (LSECs), UGCG-derived GM3 ganglioside suppresses insulin receptor-β (IRβ) in a dose-dependent manner; UGCG deficiency reverses HFD-induced IRβ downregulation, restores endothelial fenestration, and improves insulin sensitivity through NO/ET-1 signaling-mediated hepatocyte metabolic reprogramming.","method":"LSEC-specific Ugcg conditional knockout mice; primary cell sorting; LC-MS ganglioside quantitation; LSEC-hepatocyte cocultures; scanning electron microscopy of fenestration; ELISA for NO/ET-1; UGCG inhibitor (Genz-123346) treatment","journal":"Hepatology communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — cell-type-specific conditional KO in vivo plus in vitro reconstitution with cocultures, multiple orthogonal methods (LC-MS, EM, ELISA), dose-dependent GM3–IRβ relationship established","pmids":["40906894"],"is_preprint":false},{"year":2026,"finding":"UGCG glycosylates ceramide to blunt its pro-apoptotic activity in AML cells; UGCG inhibition combined with venetoclax induces ceramide accumulation that activates the ER stress GRP78/PERK/CHOP axis and activates RAB32, leading to mitochondrial fission via ER-mitochondria communication and DRP1 activation.","method":"UGCG genetic inhibition and eliglustat pharmacological inhibition in AML cells; combination with venetoclax; apoptosis assays; ER stress marker Western blots; RAB32 activation assays; DRP1/mitochondrial fission analysis; primary AML cells and xenograft models","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic and pharmacological inhibition, multiple orthogonal mechanistic readouts (ceramide accumulation, ER stress axis, RAB32-DRP1-mitochondrial fission), validated in primary cells and xenografts","pmids":["41734065"],"is_preprint":false},{"year":2025,"finding":"UGCG inhibition (via CRISPR/Cas9 UGCG knockout or Genz-161 inhibitor) re-sensitizes drug-resistant colon cancer cells with homozygous TP53 R273H mutation to chemotherapy by downregulating METTL3 expression, reducing RNA m6A methylation on mutant p53 mRNA, and diminishing cancer stem cells.","method":"CRISPR/Cas9 UGCG knockout; Genz-161 pharmacological inhibition; lipidomics (ceramide glycosylation); METTL3 Western blot/qRT-PCR; m6A modification analysis; CSC assays; tumor xenograft models","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic and pharmacological loss-of-function with lipidomics and m6A mechanistic pathway, single lab, preprint not yet peer-reviewed","pmids":["bio_10.1101_2025.11.02.686136"],"is_preprint":true},{"year":2025,"finding":"Conditional knockout of UGCG (the mammalian ortholog of Drosophila GlcT) in mouse small intestine causes excessive differentiation of goblet cells, phenocopying Notch inhibition; in Drosophila, GlcT/glucosylceramide synthase mutation causes secretory cell tumors due to deficiency in Mactosylceramide/Lactosylceramide that impairs endocytic recycling of the Notch ligand Delta, reducing Notch signaling.","method":"Conditional intestinal UGCG knockout in mice (goblet cell phenotype); Drosophila forward genetic screen; genetic analysis of GSL synthesis pathway; metabolite rescue experiments; epistasis with Notch pathway","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO in mammals plus genetic epistasis and metabolite rescue in Drosophila ortholog; multi-organism mechanistic convergence but preprint","pmids":["bio_10.1101_2025.02.04.636335"],"is_preprint":true},{"year":2024,"finding":"UGCG is required for glucose-dependent glycosphingolipid biosynthesis in CD8+ T cells; UGCG-deficient CD8+ T cells show impaired plasma membrane lipid raft integrity and aggregation following TCR stimulation, reduced granzyme expression, and defective tumor control in vivo, without affecting glucose-dependent energy production.","method":"13C stable isotope tracing (UDP-glucose tracking); UGCG genetic inhibition in CD8+ T cells; lipid raft integrity assays post-TCR stimulation; granzyme expression; in vivo tumor control assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — isotope tracing plus genetic loss-of-function with multiple orthogonal readouts (lipid raft, granzyme, in vivo), preprint not peer-reviewed","pmids":["bio_10.1101_2024.10.10.617261"],"is_preprint":true}],"current_model":"UGCG (UDP-glucose ceramide glucosyltransferase) is the rate-limiting enzyme that glycosylates ceramide to produce glucosylceramide de novo, the precursor for all glycosphingolipids; by converting pro-apoptotic ceramide into glycosphingolipids it modulates membrane lipid raft integrity, lysosomal homeostasis, ER-mitochondria communication (via ceramide-RAB32-DRP1), Notch ligand endocytic recycling, insulin receptor signaling (via GM3), ERK/NF-κB/Wnt signaling, and glucose/glutamine metabolism—thereby controlling cell survival, drug resistance, immune cell function, and tissue homeostasis across multiple cellular contexts."},"narrative":{"mechanistic_narrative":"UGCG is the rate-limiting glucosylceramide synthase that glycosylates ceramide to produce glucosylceramide de novo, the precursor for all glycosphingolipids, and through this single biochemical step it governs membrane lipid composition, organelle homeostasis, and a broad range of survival and signaling outputs [PMID:29409484, PMID:36504340]. Its in vitro activity has been directly demonstrated using deuterated ceramide as acceptor substrate with LC-MS/MS detection of glucosylceramide product, enabling kinetic and inhibitor characterization [PMID:36504340]. By converting pro-apoptotic ceramide into glycosphingolipids, UGCG promotes cell survival: in AML cells UGCG inhibition causes ceramide accumulation that triggers the GRP78/PERK/CHOP ER-stress axis and activates RAB32-driven, DRP1-dependent mitochondrial fission via ER-mitochondria communication [PMID:41734065], and its glycosphingolipid products build GM1+ membrane microdomains in plasma membranes and lysosomes that confer resistance to lysosomal autophagy inhibition [PMID:36331284]. UGCG-derived glycosphingolipids also remodel membrane lipid rafts and organellar lipid pools, supporting CD8+ T cell raft integrity and effector function [PMID:bio_10.1101_2024.10.10.617261], altering ER/mitochondrial sphingolipid composition and metabolic flux in breast cancer [PMID:31666638, PMID:32424263], and the UGCG product GM3 suppresses insulin receptor-β in liver sinusoidal endothelial cells to shape hepatic insulin sensitivity [PMID:40906894]. Downstream of this lipid output, UGCG potentiates ERK, NF-κB, Wnt/β-catenin, STAT3, Akt, and GSK3β signaling in cancer and cardiac contexts, in part through a synergistic interaction with the lactosylceramide synthase B4GalT5 [PMID:37658291, PMID:39674092, PMID:39934657]. UGCG is further required for lysosomal homeostasis and autophagic flux, controlling antiviral STING signaling [PMID:39631580], and for glycosphingolipid-dependent endocytic recycling of the Notch ligand Delta that regulates intestinal secretory-cell fate [PMID:bio_10.1101_2025.02.04.636335].","teleology":[{"year":2018,"claim":"Established UGCG as the de novo glucosylceramide synthase whose overexpression tracks with multidrug resistance, framing it as a survival-associated lipid enzyme rather than a passive metabolic step.","evidence":"Review synthesizing prior biochemical and cell biology data on GlcCer synthase activity and MDR1 correlation","pmids":["29409484"],"confidence":"Medium","gaps":["No single new experiment; enzymatic mechanism summarized not directly tested here","Causal link between UGCG and MDR1 not dissected"]},{"year":2019,"claim":"Showed that beyond lipid synthesis, UGCG reprograms nutrient metabolism, linking the enzyme to glutamine uptake and oxidative stress handling that sustain proliferation.","evidence":"UGCG overexpression in MCF-7 cells with metabolite measurements and metabolic assays","pmids":["31666638"],"confidence":"Medium","gaps":["Single cell line and lab","Mechanism connecting glycosphingolipid output to glutamine metabolism not resolved","No loss-of-function confirmation"]},{"year":2020,"claim":"Extended the metabolic role by showing UGCG shifts cells to an energetic phenotype and alters ER/mitochondrial sphingolipid composition, linking the enzyme to organelle lipid remodeling.","evidence":"UGCG overexpression in MCF-7 with Seahorse flux assays and lipidomics of subcellular fractions","pmids":["32424263"],"confidence":"Medium","gaps":["Single lab overexpression model","Causal lipid species driving metabolic shift not identified","No in vivo validation"]},{"year":2023,"claim":"Provided a direct in vitro enzymatic assay establishing UGCG kinetics and inhibitor pharmacology, anchoring downstream phenotypes to measurable catalytic activity.","evidence":"In vitro assay with deuterated ceramide substrate and LC-MS/MS product quantitation in cell homogenates and human fibroblasts","pmids":["36504340"],"confidence":"High","gaps":["No structural model of substrate engagement","Acceptor/donor specificity beyond ceramide not mapped"]},{"year":2023,"claim":"Connected UGCG glycosphingolipid output to specific membrane microdomain formation, explaining how the enzyme confers resistance to lysosomal autophagy inhibition.","evidence":"Proteomics, lipidomics, gain/loss-of-function with eliglustat in cancer cells plus syngeneic and PDX models","pmids":["36331284"],"confidence":"High","gaps":["Molecular composition and assembly of GM1+ microdomains not fully defined","How microdomains mechanistically block cell death incompletely resolved"]},{"year":2023,"claim":"Identified a direct physical partner, B4GalT5, showing UGCG acts synergistically with downstream lactosylceramide synthesis to drive cardiomyocyte hypertrophy via ERK and mitochondrial oxidative stress.","evidence":"Co-IP, UGCG knockdown/overexpression and B4GalT5 knockdown epistasis in cardiomyocytes, in vivo pressure overload model","pmids":["37658291"],"confidence":"Medium","gaps":["Co-IP without reciprocal/structural validation of the interaction interface","Whether B4GalT5 partnership operates outside cardiac context unknown"]},{"year":2024,"claim":"Demonstrated that UGCG maintains lysosomal homeostasis and autophagic flux to restrain STING signaling, revealing a role in antiviral defense.","evidence":"shRNA knockdown and pharmacological inhibition with autophagy flux assays, lysosomal pH, LC3-STING Co-IP, and in vivo PRV models","pmids":["39631580"],"confidence":"Medium","gaps":["Direct lipid mediator linking UGCG to lysosomal pH not identified","Single lab"]},{"year":2024,"claim":"Linked UGCG to NF-κB and Wnt/β-catenin pathway activation underlying chemoresistance and malignant progression in TNBC.","evidence":"Gain/loss-of-function in TNBC lines with pathway inhibitor rescue","pmids":["39674092"],"confidence":"Medium","gaps":["How glycosphingolipid output activates these pathways mechanistically unclear","No in vivo confirmation of pathway dependency"]},{"year":2024,"claim":"Suggested UGCG remodels endosomal membranes affecting cargo trafficking, by showing overexpression relieves endosomal polyplex sequestration.","evidence":"UGCG overexpression in HEK293 with transfection efficiency and endosomal imaging readouts","pmids":["38327808"],"confidence":"Low","gaps":["Single functional readout with mechanistic link inferred not demonstrated","No loss-of-function or lipid-level confirmation"]},{"year":2025,"claim":"Showed UGCG supports β-adrenergic-driven cardiac fibrosis through ERK, STAT3, Akt and GSK3β signaling, identifying it as a druggable node with miglustat.","evidence":"siRNA knockdown in primary cardiac fibroblasts plus in vivo isoproterenol model with miglustat","pmids":["39934657"],"confidence":"Medium","gaps":["Direct lipid species coupling UGCG to these kinases not defined","Single lab"]},{"year":2025,"claim":"Established that the specific UGCG product GM3 suppresses insulin receptor-β in liver endothelial cells, mechanistically connecting glycosphingolipid synthesis to systemic insulin sensitivity.","evidence":"LSEC-specific conditional Ugcg knockout mice, LC-MS ganglioside quantitation, EM of fenestration, cocultures and inhibitor treatment","pmids":["40906894"],"confidence":"High","gaps":["Molecular basis of GM3-IRβ interaction not structurally defined","Generality across endothelial beds untested"]},{"year":2026,"claim":"Defined the survival mechanism most directly: UGCG glycosylates ceramide to blunt apoptosis, and its inhibition triggers an ER-stress and RAB32/DRP1 mitochondrial-fission axis that synergizes with venetoclax in AML.","evidence":"Genetic and eliglustat inhibition with venetoclax, ER-stress and RAB32 activation assays, mitochondrial fission analysis in primary AML cells and xenografts","pmids":["41734065"],"confidence":"High","gaps":["Spatial details of ceramide-driven ER-mitochondria contact remodeling incomplete","Whether axis generalizes beyond AML untested"]},{"year":2025,"claim":"Connected UGCG to RNA m6A regulation, showing its inhibition downregulates METTL3 to destabilize mutant p53 mRNA and reduce cancer stem cells, re-sensitizing resistant colon cancer.","evidence":"CRISPR knockout and Genz-161 inhibition with lipidomics, m6A and METTL3 analysis, xenografts (preprint)","pmids":["bio_10.1101_2025.11.02.686136"],"confidence":"Medium","gaps":["Preprint not peer-reviewed","Mechanistic link from glycosphingolipids to METTL3 expression unresolved"]},{"year":2025,"claim":"Revealed a developmental role: UGCG/GlcT glycosphingolipid output drives Notch-ligand Delta endocytic recycling, controlling secretory-cell fate in mammalian intestine and Drosophila.","evidence":"Conditional intestinal UGCG knockout in mice and Drosophila genetic epistasis with metabolite rescue (preprint)","pmids":["bio_10.1101_2025.02.04.636335"],"confidence":"Medium","gaps":["Preprint not peer-reviewed","Direct demonstration of which GSL species mediates Delta recycling in mammals incomplete"]},{"year":2024,"claim":"Showed UGCG-dependent glycosphingolipid synthesis is required for CD8+ T cell lipid raft integrity and effector function, linking the enzyme to anti-tumor immunity.","evidence":"13C UDP-glucose tracing and genetic inhibition in CD8+ T cells with raft, granzyme and in vivo tumor readouts (preprint)","pmids":["bio_10.1101_2024.10.10.617261"],"confidence":"Medium","gaps":["Preprint not peer-reviewed","Which raft glycosphingolipids sustain TCR signaling not pinpointed"]},{"year":null,"claim":"How a single glucosylceramide synthase coordinates such divergent outputs—ER-stress survival, membrane microdomains, ganglioside-receptor regulation, Notch recycling, and immune raft signaling—through distinct downstream glycosphingolipid species remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of UGCG catalysis or substrate selectivity","Specific glycosphingolipid species mediating each phenotype not individually mapped","Mechanism coupling lipid product to NF-κB/Wnt/STAT3 signaling not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,4,5]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[2,11]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[2,11]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[3,14]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[3,6]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[3,6]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[11]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[8,9,10]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6,14]}],"complexes":[],"partners":["B4GALT5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q16739","full_name":"Ceramide glucosyltransferase","aliases":["GLCT-1","Glucosylceramide synthase","GCS","Glycosylceramide synthase","UDP-glucose ceramide glucosyltransferase","UDP-glucose:N-acylsphingosine D-glucosyltransferase"],"length_aa":394,"mass_kda":44.9,"function":"Participates in the initial step of the glucosylceramide-based glycosphingolipid/GSL synthetic pathway at the cytosolic surface of the Golgi (PubMed:1532799, PubMed:8643456). Catalyzes the transfer of glucose from UDP-glucose to ceramide to produce glucosylceramide/GlcCer (such as beta-D-glucosyl-(1<->1')-N-acylsphing-4-enine) (PubMed:1532799, PubMed:8643456). GlcCer is the core component of glycosphingolipids/GSLs, amphipathic molecules consisting of a ceramide lipid moiety embedded in the outer leaflet of the membrane, linked to one of hundreds of different externally oriented oligosaccharide structures (PubMed:8643456). Glycosphingolipids are essential components of membrane microdomains that mediate membrane trafficking and signal transduction, implicated in many fundamental cellular processes, including growth, differentiation, migration, morphogenesis, cell-to-cell and cell-to-matrix interactions (By similarity). They are required for instance in the proper development and functioning of the nervous system (By similarity). As an example of their role in signal transduction, they regulate the leptin receptor/LEPR in the leptin-mediated signaling pathway (By similarity). They also play an important role in the establishment of the skin barrier regulating keratinocyte differentiation and the proper assembly of the cornified envelope (By similarity). The biosynthesis of GSLs is also required for the proper intestinal endocytic uptake of nutritional lipids (By similarity). Catalyzes the synthesis of xylosylceramide/XylCer (such as beta-D-xylosyl-(1<->1')-N-acylsphing-4-enine) using UDP-Xyl as xylose donor (PubMed:33361282)","subcellular_location":"Golgi apparatus membrane","url":"https://www.uniprot.org/uniprotkb/Q16739/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/UGCG","classification":"Not Classified","n_dependent_lines":119,"n_total_lines":1208,"dependency_fraction":0.09850993377483444},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/UGCG","total_profiled":1310},"omim":[{"mim_id":"602874","title":"UDP-GLUCOSE CERAMIDE GLUCOSYLTRANSFERASE; UGCG","url":"https://www.omim.org/entry/602874"},{"mim_id":"242300","title":"ICHTHYOSIS, CONGENITAL, AUTOSOMAL RECESSIVE 1; ARCI1","url":"https://www.omim.org/entry/242300"},{"mim_id":"231000","title":"GAUCHER DISEASE, TYPE III; GD3","url":"https://www.omim.org/entry/231000"},{"mim_id":"230800","title":"GAUCHER DISEASE, TYPE I; GD1","url":"https://www.omim.org/entry/230800"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"bone marrow","ntpm":106.7}],"url":"https://www.proteinatlas.org/search/UGCG"},"hgnc":{"alias_symbol":["GCS"],"prev_symbol":[]},"alphafold":{"accession":"Q16739","domains":[{"cath_id":"3.90.550.10","chopping":"40-276","consensus_level":"medium","plddt":93.7499,"start":40,"end":276}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q16739","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q16739-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q16739-F1-predicted_aligned_error_v6.png","plddt_mean":93.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=UGCG","jax_strain_url":"https://www.jax.org/strain/search?query=UGCG"},"sequence":{"accession":"Q16739","fasta_url":"https://rest.uniprot.org/uniprotkb/Q16739.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q16739/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q16739"}},"corpus_meta":[{"pmid":"29409484","id":"PMC_29409484","title":"The UDP-glucose ceramide glycosyltransferase (UGCG) and the link to multidrug resistance protein 1 (MDR1).","date":"2018","source":"BMC cancer","url":"https://pubmed.ncbi.nlm.nih.gov/29409484","citation_count":51,"is_preprint":false},{"pmid":"32424263","id":"PMC_32424263","title":"UGCG overexpression leads to increased glycolysis and increased oxidative phosphorylation of breast cancer cells.","date":"2020","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/32424263","citation_count":41,"is_preprint":false},{"pmid":"36331284","id":"PMC_36331284","title":"Targeting UGCG Overcomes Resistance to Lysosomal Autophagy Inhibition.","date":"2023","source":"Cancer discovery","url":"https://pubmed.ncbi.nlm.nih.gov/36331284","citation_count":31,"is_preprint":false},{"pmid":"31666638","id":"PMC_31666638","title":"UGCG influences glutamine metabolism of breast cancer cells.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31666638","citation_count":28,"is_preprint":false},{"pmid":"9601049","id":"PMC_9601049","title":"Structural features of the UCCG and UGCG tetraloops in very short hairpins as evidenced by optical spectroscopy.","date":"1998","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9601049","citation_count":18,"is_preprint":false},{"pmid":"37658291","id":"PMC_37658291","title":"UGCG modulates heart hypertrophy through B4GalT5-mediated mitochondrial oxidative stress and the ERK signaling pathway.","date":"2023","source":"Cellular & molecular biology letters","url":"https://pubmed.ncbi.nlm.nih.gov/37658291","citation_count":14,"is_preprint":false},{"pmid":"38327808","id":"PMC_38327808","title":"Extracellular vesicle depletion and UGCG overexpression mitigate the cell density effect in HEK293 cell culture transfection.","date":"2024","source":"Molecular therapy. 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UGCG overexpression correlates with MDR1 expression and influences lipid composition of membranes in multidrug-resistant cells.\",\n      \"method\": \"Review synthesizing biochemical and cell biology data; UGCG enzymatic function as GlcCer synthase established by prior biochemical work summarized herein\",\n      \"journal\": \"BMC cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — review paper synthesizing multiple prior experimental studies establishing UGCG enzymatic activity and MDR1 correlation; no single new experiment presented\",\n      \"pmids\": [\"29409484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"UGCG overexpression in breast cancer cells adapts glutamine metabolism under nutrient-poor conditions, increasing glutamine uptake for oxidative stress response (via elevated GSR/GSH) and fueling the TCA cycle to maintain proliferative advantage.\",\n      \"method\": \"UGCG overexpression in MCF-7 cells; mRNA expression analysis, metabolite measurements (GSH, glutamine), functional metabolic assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single lab, multiple metabolic readouts but no reconstitution or epistasis; functional link established by OE with specific metabolic phenotype\",\n      \"pmids\": [\"31666638\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"UGCG overexpression in breast cancer cells shifts cellular metabolism from quiescent/aerobic to an energetic phenotype by increasing both glycolysis and oxidative glucose metabolism, and alters sphingolipid composition of ER/mitochondria fractions contributing to increased mitochondrial turnover.\",\n      \"method\": \"UGCG overexpression in MCF-7 cells; Seahorse metabolic flux assays, lipidomics of ER/mitochondria fractions, mitochondrial mass/turnover markers\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — single lab, two orthogonal methods (metabolic flux + lipidomics with fractionation), defined cellular phenotype\",\n      \"pmids\": [\"32424263\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"UGCG drives resistance to lysosomal autophagy inhibition (LAI) by producing glycosphingolipids that promote GM1+ membrane microdomain (GMM) formation in plasma membranes and lysosomes; UGCG inhibition decreases LAI-induced GMMs and augments cell death, while UGCG overexpression confers LAI resistance.\",\n      \"method\": \"Proteomics, lipidomics, immunoblotting, UGCG inhibition (eliglustat) and overexpression in cancer cell lines; syngeneic tumor and patient-derived xenograft models\",\n      \"journal\": \"Cancer discovery\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (proteomics, lipidomics, gain- and loss-of-function), replicated in cell lines and in vivo models\",\n      \"pmids\": [\"36331284\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"UGCG enzymatic activity can be measured in vitro using deuterated ceramide as acceptor substrate and LC-MS/MS quantitation of deuterated glucosylceramide product; kinetic parameters of UGCG and inhibition by GZ667161 were determined in model cells and human fibroblasts.\",\n      \"method\": \"In vitro enzyme activity assay with deuterated ceramide substrate; LC-MS/MS quantitation; inhibitor dose-response in cell homogenates\",\n      \"journal\": \"Glycobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro enzymatic assay with substrate, kinetic parameter determination, and inhibitor characterization; single lab but rigorous biochemical approach\",\n      \"pmids\": [\"36504340\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"UGCG physically interacts with B4GalT5 (beta-1,4-galactosyltransferase 5, which catalyzes lactosylceramide synthesis); this interaction is synergistic, and limiting B4GalT5 expression impairs UGCG's capacity to promote cardiomyocyte hypertrophy. UGCG modulates heart hypertrophy through mitochondrial oxidative stress and ERK signaling activation.\",\n      \"method\": \"Co-immunoprecipitation identifying UGCG–B4GalT5 interaction; UGCG knockdown and overexpression in cardiomyocytes; B4GalT5 knockdown epistasis; ERK signaling pathway analysis; in vivo pressure overload model\",\n      \"journal\": \"Cellular & molecular biology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP for interaction plus genetic epistasis (B4GalT5 KD rescues UGCG OE phenotype), single lab\",\n      \"pmids\": [\"37658291\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"UGCG inhibition suppresses pseudorabies virus (PRV) infection by disrupting lysosomal homeostasis (altered lysosomal pH, impaired lysosome-associated proteins), blocking autophagic flux, and preventing LC3-STING complex formation, thereby sustaining STING signaling activation that resists PRV infection.\",\n      \"method\": \"shRNA knockdown and pharmacological inhibition (eliglustat, ibiglustat) of UGCG; autophagy flux assays (LC3-II conversion), lysosomal pH measurement, STING signaling analysis, LC3-STING co-immunoprecipitation; in vivo efficacy evaluation\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (KD + pharmacological inhibition, lysosomal assays, Co-IP, in vivo), single lab\",\n      \"pmids\": [\"39631580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"UGCG overexpression in HEK293 cells removes intracellular polyplex sequestration in endosomes, improving transfection efficiency; this indicates UGCG activity influences endosomal membrane composition and polyplex trafficking.\",\n      \"method\": \"UGCG overexpression in HEK293 cells; transfection efficiency assays, VLP production quantitation, endosomal sequestration imaging\",\n      \"journal\": \"Molecular therapy. Methods & clinical development\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single functional readout (transfection efficiency), mechanistic link to endosomal biology inferred but not deeply characterized\",\n      \"pmids\": [\"38327808\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"UGCG promotes chemoresistance and malignant progression of triple-negative breast cancer by amplifying NF-κB and Wnt/β-catenin pathway activation; inhibitors of these pathways diminish UGCG-induced malignant effects.\",\n      \"method\": \"Gain- and loss-of-function experiments in TNBC cell lines; Western blotting, qRT-PCR for NF-κB and Wnt/β-catenin pathway components; pathway inhibitor rescue experiments\",\n      \"journal\": \"Translational oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — gain/loss-of-function with pathway inhibitor rescue across two pathways, single lab, no reconstitution\",\n      \"pmids\": [\"39674092\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Miglustat ameliorates isoproterenol-induced cardiac fibrosis by targeting UGCG; UGCG knockdown in primary cardiac fibroblasts suppresses ERK, STAT3, Akt, and GSK3β signaling activated by β-adrenergic receptor overactivation.\",\n      \"method\": \"UGCG siRNA knockdown in primary cardiac fibroblasts; in vivo isoproterenol cardiac fibrosis model with miglustat treatment; Western blotting for signaling pathways; GEO data validation\",\n      \"journal\": \"Molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function in primary cells plus in vivo pharmacological inhibition, multiple signaling pathway readouts, single lab\",\n      \"pmids\": [\"39934657\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In liver sinusoidal endothelial cells (LSECs), UGCG-derived GM3 ganglioside suppresses insulin receptor-β (IRβ) in a dose-dependent manner; UGCG deficiency reverses HFD-induced IRβ downregulation, restores endothelial fenestration, and improves insulin sensitivity through NO/ET-1 signaling-mediated hepatocyte metabolic reprogramming.\",\n      \"method\": \"LSEC-specific Ugcg conditional knockout mice; primary cell sorting; LC-MS ganglioside quantitation; LSEC-hepatocyte cocultures; scanning electron microscopy of fenestration; ELISA for NO/ET-1; UGCG inhibitor (Genz-123346) treatment\",\n      \"journal\": \"Hepatology communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — cell-type-specific conditional KO in vivo plus in vitro reconstitution with cocultures, multiple orthogonal methods (LC-MS, EM, ELISA), dose-dependent GM3–IRβ relationship established\",\n      \"pmids\": [\"40906894\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"UGCG glycosylates ceramide to blunt its pro-apoptotic activity in AML cells; UGCG inhibition combined with venetoclax induces ceramide accumulation that activates the ER stress GRP78/PERK/CHOP axis and activates RAB32, leading to mitochondrial fission via ER-mitochondria communication and DRP1 activation.\",\n      \"method\": \"UGCG genetic inhibition and eliglustat pharmacological inhibition in AML cells; combination with venetoclax; apoptosis assays; ER stress marker Western blots; RAB32 activation assays; DRP1/mitochondrial fission analysis; primary AML cells and xenograft models\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic and pharmacological inhibition, multiple orthogonal mechanistic readouts (ceramide accumulation, ER stress axis, RAB32-DRP1-mitochondrial fission), validated in primary cells and xenografts\",\n      \"pmids\": [\"41734065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"UGCG inhibition (via CRISPR/Cas9 UGCG knockout or Genz-161 inhibitor) re-sensitizes drug-resistant colon cancer cells with homozygous TP53 R273H mutation to chemotherapy by downregulating METTL3 expression, reducing RNA m6A methylation on mutant p53 mRNA, and diminishing cancer stem cells.\",\n      \"method\": \"CRISPR/Cas9 UGCG knockout; Genz-161 pharmacological inhibition; lipidomics (ceramide glycosylation); METTL3 Western blot/qRT-PCR; m6A modification analysis; CSC assays; tumor xenograft models\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic and pharmacological loss-of-function with lipidomics and m6A mechanistic pathway, single lab, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.11.02.686136\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Conditional knockout of UGCG (the mammalian ortholog of Drosophila GlcT) in mouse small intestine causes excessive differentiation of goblet cells, phenocopying Notch inhibition; in Drosophila, GlcT/glucosylceramide synthase mutation causes secretory cell tumors due to deficiency in Mactosylceramide/Lactosylceramide that impairs endocytic recycling of the Notch ligand Delta, reducing Notch signaling.\",\n      \"method\": \"Conditional intestinal UGCG knockout in mice (goblet cell phenotype); Drosophila forward genetic screen; genetic analysis of GSL synthesis pathway; metabolite rescue experiments; epistasis with Notch pathway\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO in mammals plus genetic epistasis and metabolite rescue in Drosophila ortholog; multi-organism mechanistic convergence but preprint\",\n      \"pmids\": [\"bio_10.1101_2025.02.04.636335\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"UGCG is required for glucose-dependent glycosphingolipid biosynthesis in CD8+ T cells; UGCG-deficient CD8+ T cells show impaired plasma membrane lipid raft integrity and aggregation following TCR stimulation, reduced granzyme expression, and defective tumor control in vivo, without affecting glucose-dependent energy production.\",\n      \"method\": \"13C stable isotope tracing (UDP-glucose tracking); UGCG genetic inhibition in CD8+ T cells; lipid raft integrity assays post-TCR stimulation; granzyme expression; in vivo tumor control assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — isotope tracing plus genetic loss-of-function with multiple orthogonal readouts (lipid raft, granzyme, in vivo), preprint not peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2024.10.10.617261\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"UGCG (UDP-glucose ceramide glucosyltransferase) is the rate-limiting enzyme that glycosylates ceramide to produce glucosylceramide de novo, the precursor for all glycosphingolipids; by converting pro-apoptotic ceramide into glycosphingolipids it modulates membrane lipid raft integrity, lysosomal homeostasis, ER-mitochondria communication (via ceramide-RAB32-DRP1), Notch ligand endocytic recycling, insulin receptor signaling (via GM3), ERK/NF-κB/Wnt signaling, and glucose/glutamine metabolism—thereby controlling cell survival, drug resistance, immune cell function, and tissue homeostasis across multiple cellular contexts.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"UGCG is the rate-limiting glucosylceramide synthase that glycosylates ceramide to produce glucosylceramide de novo, the precursor for all glycosphingolipids, and through this single biochemical step it governs membrane lipid composition, organelle homeostasis, and a broad range of survival and signaling outputs [#0, #4]. Its in vitro activity has been directly demonstrated using deuterated ceramide as acceptor substrate with LC-MS/MS detection of glucosylceramide product, enabling kinetic and inhibitor characterization [#4]. By converting pro-apoptotic ceramide into glycosphingolipids, UGCG promotes cell survival: in AML cells UGCG inhibition causes ceramide accumulation that triggers the GRP78/PERK/CHOP ER-stress axis and activates RAB32-driven, DRP1-dependent mitochondrial fission via ER-mitochondria communication [#11], and its glycosphingolipid products build GM1+ membrane microdomains in plasma membranes and lysosomes that confer resistance to lysosomal autophagy inhibition [#3]. UGCG-derived glycosphingolipids also remodel membrane lipid rafts and organellar lipid pools, supporting CD8+ T cell raft integrity and effector function [#14], altering ER/mitochondrial sphingolipid composition and metabolic flux in breast cancer [#1, #2], and the UGCG product GM3 suppresses insulin receptor-β in liver sinusoidal endothelial cells to shape hepatic insulin sensitivity [#10]. Downstream of this lipid output, UGCG potentiates ERK, NF-κB, Wnt/β-catenin, STAT3, Akt, and GSK3β signaling in cancer and cardiac contexts, in part through a synergistic interaction with the lactosylceramide synthase B4GalT5 [#5, #8, #9]. UGCG is further required for lysosomal homeostasis and autophagic flux, controlling antiviral STING signaling [#6], and for glycosphingolipid-dependent endocytic recycling of the Notch ligand Delta that regulates intestinal secretory-cell fate [#13].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2018,\n      \"claim\": \"Established UGCG as the de novo glucosylceramide synthase whose overexpression tracks with multidrug resistance, framing it as a survival-associated lipid enzyme rather than a passive metabolic step.\",\n      \"evidence\": \"Review synthesizing prior biochemical and cell biology data on GlcCer synthase activity and MDR1 correlation\",\n      \"pmids\": [\"29409484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No single new experiment; enzymatic mechanism summarized not directly tested here\", \"Causal link between UGCG and MDR1 not dissected\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showed that beyond lipid synthesis, UGCG reprograms nutrient metabolism, linking the enzyme to glutamine uptake and oxidative stress handling that sustain proliferation.\",\n      \"evidence\": \"UGCG overexpression in MCF-7 cells with metabolite measurements and metabolic assays\",\n      \"pmids\": [\"31666638\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single cell line and lab\", \"Mechanism connecting glycosphingolipid output to glutamine metabolism not resolved\", \"No loss-of-function confirmation\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended the metabolic role by showing UGCG shifts cells to an energetic phenotype and alters ER/mitochondrial sphingolipid composition, linking the enzyme to organelle lipid remodeling.\",\n      \"evidence\": \"UGCG overexpression in MCF-7 with Seahorse flux assays and lipidomics of subcellular fractions\",\n      \"pmids\": [\"32424263\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab overexpression model\", \"Causal lipid species driving metabolic shift not identified\", \"No in vivo validation\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Provided a direct in vitro enzymatic assay establishing UGCG kinetics and inhibitor pharmacology, anchoring downstream phenotypes to measurable catalytic activity.\",\n      \"evidence\": \"In vitro assay with deuterated ceramide substrate and LC-MS/MS product quantitation in cell homogenates and human fibroblasts\",\n      \"pmids\": [\"36504340\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural model of substrate engagement\", \"Acceptor/donor specificity beyond ceramide not mapped\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Connected UGCG glycosphingolipid output to specific membrane microdomain formation, explaining how the enzyme confers resistance to lysosomal autophagy inhibition.\",\n      \"evidence\": \"Proteomics, lipidomics, gain/loss-of-function with eliglustat in cancer cells plus syngeneic and PDX models\",\n      \"pmids\": [\"36331284\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular composition and assembly of GM1+ microdomains not fully defined\", \"How microdomains mechanistically block cell death incompletely resolved\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified a direct physical partner, B4GalT5, showing UGCG acts synergistically with downstream lactosylceramide synthesis to drive cardiomyocyte hypertrophy via ERK and mitochondrial oxidative stress.\",\n      \"evidence\": \"Co-IP, UGCG knockdown/overexpression and B4GalT5 knockdown epistasis in cardiomyocytes, in vivo pressure overload model\",\n      \"pmids\": [\"37658291\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Co-IP without reciprocal/structural validation of the interaction interface\", \"Whether B4GalT5 partnership operates outside cardiac context unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrated that UGCG maintains lysosomal homeostasis and autophagic flux to restrain STING signaling, revealing a role in antiviral defense.\",\n      \"evidence\": \"shRNA knockdown and pharmacological inhibition with autophagy flux assays, lysosomal pH, LC3-STING Co-IP, and in vivo PRV models\",\n      \"pmids\": [\"39631580\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct lipid mediator linking UGCG to lysosomal pH not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Linked UGCG to NF-κB and Wnt/β-catenin pathway activation underlying chemoresistance and malignant progression in TNBC.\",\n      \"evidence\": \"Gain/loss-of-function in TNBC lines with pathway inhibitor rescue\",\n      \"pmids\": [\"39674092\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How glycosphingolipid output activates these pathways mechanistically unclear\", \"No in vivo confirmation of pathway dependency\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Suggested UGCG remodels endosomal membranes affecting cargo trafficking, by showing overexpression relieves endosomal polyplex sequestration.\",\n      \"evidence\": \"UGCG overexpression in HEK293 with transfection efficiency and endosomal imaging readouts\",\n      \"pmids\": [\"38327808\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single functional readout with mechanistic link inferred not demonstrated\", \"No loss-of-function or lipid-level confirmation\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showed UGCG supports β-adrenergic-driven cardiac fibrosis through ERK, STAT3, Akt and GSK3β signaling, identifying it as a druggable node with miglustat.\",\n      \"evidence\": \"siRNA knockdown in primary cardiac fibroblasts plus in vivo isoproterenol model with miglustat\",\n      \"pmids\": [\"39934657\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct lipid species coupling UGCG to these kinases not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Established that the specific UGCG product GM3 suppresses insulin receptor-β in liver endothelial cells, mechanistically connecting glycosphingolipid synthesis to systemic insulin sensitivity.\",\n      \"evidence\": \"LSEC-specific conditional Ugcg knockout mice, LC-MS ganglioside quantitation, EM of fenestration, cocultures and inhibitor treatment\",\n      \"pmids\": [\"40906894\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of GM3-IRβ interaction not structurally defined\", \"Generality across endothelial beds untested\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined the survival mechanism most directly: UGCG glycosylates ceramide to blunt apoptosis, and its inhibition triggers an ER-stress and RAB32/DRP1 mitochondrial-fission axis that synergizes with venetoclax in AML.\",\n      \"evidence\": \"Genetic and eliglustat inhibition with venetoclax, ER-stress and RAB32 activation assays, mitochondrial fission analysis in primary AML cells and xenografts\",\n      \"pmids\": [\"41734065\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Spatial details of ceramide-driven ER-mitochondria contact remodeling incomplete\", \"Whether axis generalizes beyond AML untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected UGCG to RNA m6A regulation, showing its inhibition downregulates METTL3 to destabilize mutant p53 mRNA and reduce cancer stem cells, re-sensitizing resistant colon cancer.\",\n      \"evidence\": \"CRISPR knockout and Genz-161 inhibition with lipidomics, m6A and METTL3 analysis, xenografts (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.11.02.686136\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint not peer-reviewed\", \"Mechanistic link from glycosphingolipids to METTL3 expression unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Revealed a developmental role: UGCG/GlcT glycosphingolipid output drives Notch-ligand Delta endocytic recycling, controlling secretory-cell fate in mammalian intestine and Drosophila.\",\n      \"evidence\": \"Conditional intestinal UGCG knockout in mice and Drosophila genetic epistasis with metabolite rescue (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.02.04.636335\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint not peer-reviewed\", \"Direct demonstration of which GSL species mediates Delta recycling in mammals incomplete\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed UGCG-dependent glycosphingolipid synthesis is required for CD8+ T cell lipid raft integrity and effector function, linking the enzyme to anti-tumor immunity.\",\n      \"evidence\": \"13C UDP-glucose tracing and genetic inhibition in CD8+ T cells with raft, granzyme and in vivo tumor readouts (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.10.10.617261\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint not peer-reviewed\", \"Which raft glycosphingolipids sustain TCR signaling not pinpointed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single glucosylceramide synthase coordinates such divergent outputs—ER-stress survival, membrane microdomains, ganglioside-receptor regulation, Notch recycling, and immune raft signaling—through distinct downstream glycosphingolipid species remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of UGCG catalysis or substrate selectivity\", \"Specific glycosphingolipid species mediating each phenotype not individually mapped\", \"Mechanism coupling lipid product to NF-κB/Wnt/STAT3 signaling not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 4, 5]},\n      {\"term_id\": \"GO:0016758\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [2, 11]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [2, 11]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [3, 14]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [3, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [3, 6]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [8, 9, 10]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6, 14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"B4GALT5\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}