{"gene":"GALNT6","run_date":"2026-06-10T01:55:20","timeline":{"discoveries":[{"year":1999,"finding":"GALNT6 (GalNAc-T6) encodes a UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase that catalyzes O-GalNAc transfer to peptide substrates; its acceptor substrate specificities overlap with but are distinct from other GalNAc-transferases, and despite high sequence similarity to GALNT3 the two enzymes do not provide full functional redundancy.","method":"In vitro enzymatic activity assays with defined acceptor peptides; Northern analysis; immunocytology with monoclonal antibodies; genomic cloning and sequence analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in vitro enzymatic assay with defined substrates, replicated across multiple orthogonal methods in founding characterization paper","pmids":["10464263"],"is_preprint":false},{"year":2017,"finding":"GALNT6 O-glycosylates EGFR, increasing EGFR phosphorylation and downstream signaling in ovarian cancer cells; GALNT6 knockdown reduced EGFR phosphorylation and the enhanced invasive behavior was reversed by the EGFR inhibitor erlotinib.","method":"siRNA knockdown; phospho-RTK array; Western blot; VVA lectin pull-down assay to detect O-GalNAc modification of EGFR; GALNT6 overexpression","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — lectin pulldown plus functional rescue with pharmacological EGFR inhibitor, single lab with two orthogonal methods","pmids":["28388560"],"is_preprint":false},{"year":2016,"finding":"GALNT6 directly O-glycosylates amyloid precursor protein (APP), and excess O-glycosylation of APP by GALNT6 reduces both Aβ1-40 and Aβ1-42 production without significantly altering α- or β-secretase activities, suggesting steric hindrance of secretase cleavage.","method":"Transfection of GALNT6 into HEK293T cells; in vitro GalNAc-T enzymatic activity assay on soluble APP; ELISA for Aβ; secretase activity assays","journal":"Journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — direct in vitro enzymatic assay on APP substrate, single lab with multiple readouts","pmids":["28053144"],"is_preprint":false},{"year":2016,"finding":"GALNT6 knockdown in pancreatic cancer cells decreased MUC4 protein and transcript levels, reduced HER2 and ERK levels, suppressed viability, and caused cadherin switching from P-cadherin to E-cadherin, indicating GALNT6 O-glycosylation activity is required for MUC4 stability and maintenance of a mesenchymal phenotype.","method":"siRNA knockdown; Western blot; RT-PCR; cell viability assay; immunofluorescence for cadherin switching","journal":"Neoplasia (New York, N.Y.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KD with defined molecular and phenotypic readouts, single lab","pmids":["27237318"],"is_preprint":false},{"year":2017,"finding":"GALNT6 O-glycosylates GRP78 (HSPA5/BiP); this O-glycosylation stabilizes GRP78 protein, retains it in the ER, and enhances its anti-apoptotic function. Conversely, overexpression of GRP78 promotes Golgi-to-ER relocation of GALNT6, indicating a reciprocal regulatory loop.","method":"VVA lectin pull-down followed by mass spectrometry to identify GRP78 as GALNT6 substrate; co-immunoprecipitation; Western blot; immunofluorescence for subcellular localization; GALNT6 knockdown/overexpression with apoptosis readout","journal":"Neoplasia (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 2 / Strong — lectin pulldown-MS substrate identification plus functional validation (localization, stability, apoptosis) in a single lab with multiple orthogonal methods","pmids":["28110670"],"is_preprint":false},{"year":2017,"finding":"De novo expression of GALNT6 in colon cancer cells drives a cancer-like dysplastic growth pattern; GALNT6 knockout restores more normal differentiation, reduces proliferation, and normalizes cell-cell adhesion. O-glycoproteomic analysis identified a specific set of GALNT6-unique substrates distinct from those of the closely related GALNT3.","method":"Precise gene targeting (CRISPR-based) knockout/rescue in isogenic cell lines; O-glycoproteomics; tissue culture differentiation assay; proliferation assay; cell-cell adhesion assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — isogenic KO/rescue system combined with quantitative O-glycoproteomics and multiple orthogonal functional assays","pmids":["29187600"],"is_preprint":false},{"year":2018,"finding":"GALNT6 O-glycosylates estrogen receptor alpha (ERα) at Ser573 in its F domain; this modification is required for ERα protein stability and nuclear localization in breast cancer cells. GALNT6 knockdown reduces ERα protein abundance, causes loss of nuclear ERα, and downregulates ERα target genes (MYC, CCND1, CTSD).","method":"siRNA knockdown; immunocytochemistry; LC-MS/MS identification of O-glycosylation site (Ser573); co-immunoprecipitation; cell-permeable peptide competition assay","journal":"Neoplasia (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 1 / Strong — site-specific O-glycosylation identified by LC-MS/MS, functional validation by localization and gene expression, multiple orthogonal methods in one study","pmids":["30208353"],"is_preprint":false},{"year":2019,"finding":"GALNT6 O-glycosylates LGALS3BP at three sites (Thr556, Thr571, Ser582); this glycosylation is required for LGALS3BP secretion and its autocrine growth-promoting activity in breast cancer. Triple alanine substitution (T556A/T571A/S582A) in LGALS3BP abolished GALNT6-dependent glycosylation, secretion, and autocrine growth.","method":"siRNA knockdown; VVA lectin pull-down; site-directed mutagenesis of glycosylation sites; secretion assay; breast cancer cell proliferation assay","journal":"International journal of oncology","confidence":"High","confidence_rationale":"Tier 1 / Strong — site-directed mutagenesis of glycosylation sites combined with secretion and growth assays, multiple orthogonal methods demonstrating mechanistic causality","pmids":["31894262"],"is_preprint":false},{"year":2019,"finding":"GALNT6 interacts with MUC1-N and promotes tumorigenicity and metastasis through the β-catenin/MUC1-C signaling pathway; GALNT6 knockdown reduces nuclear β-catenin and MUC1-C levels and decreases downstream targets PCNA, cyclin D1, and c-Myc while increasing E-cadherin.","method":"Co-immunoprecipitation (GALNT6 with MUC1-N; β-catenin with MUC1-C); cell fractionation assay; siRNA knockdown; Western blot","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP for binding plus cell fractionation and KD phenotype, single lab","pmids":["30662357"],"is_preprint":false},{"year":2020,"finding":"GALNT6 O-glycosylates alpha-2-macroglobulin (α2M), and this modification activates downstream PI3K/Akt signaling to promote breast cancer cell migration and invasion.","method":"Glycosylomics analysis of supernatants from breast cancer cells; VVA lectin blot; siRNA knockdown; Western blot for PI3K/Akt; migration and invasion assays","journal":"Aging","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — glycosylomics-based substrate identification plus functional assay, single lab","pmids":["32559179"],"is_preprint":false},{"year":2020,"finding":"GALNT6 directly interacts with and O-glycosylates chaperone GRP78 in lung adenocarcinoma cells; this modification promotes epithelial-mesenchymal transition by enhancing MEK1/2–ERK1/2 signaling.","method":"Co-immunoprecipitation; VVA lectin pull-down; GALNT6 overexpression/silencing; Western blot for MEK/ERK; in vivo xenograft metastasis assay","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP and lectin pulldown with downstream signaling readout, single lab","pmids":["32393740"],"is_preprint":false},{"year":2022,"finding":"RUNX3 transcription factor binds the GALNT6 promoter and activates GALNT6 transcription; GALNT6-mediated O-glycosylation of MUC1 prevents its degradation and is required for HCC cell migration and invasion.","method":"Chromatin immunoprecipitation / promoter binding assay; RT-qPCR; Western blot; siRNA knockdown; MUC1 overexpression rescue experiment","journal":"Disease markers","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — promoter-binding assay identifies upstream regulator, functional rescue confirms MUC1 as effector substrate, single lab","pmids":["35909886"],"is_preprint":false},{"year":2023,"finding":"GALNT6 suppresses pyroptosis in pancreatic ductal adenocarcinoma by O-glycosylating NF-κB, inhibiting its nuclear translocation and thereby repressing NLRP3/GSDMD expression; additionally, GALNT6 promotes proteasomal degradation of GSDME via O-glycosylation, collectively blocking pyroptotic cell death.","method":"siRNA knockdown; Western blot; immunofluorescence for NF-κB localization; ELISA for IL-1β, IL-6, TNF-α, IL-18; scanning electron microscopy for pyroptosis morphology; qRT-PCR","journal":"Frontiers in oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD with localization and proteolysis readouts for two substrates, single lab with multiple orthogonal methods","pmids":["36925932"],"is_preprint":false},{"year":2024,"finding":"GALNT6 O-glycosylates prohibitin 2 (PHB2) at Ser161; this modification is required for GALNT6-induced ccRCC cell proliferation, migration, and invasion. LEDGF was identified as an upstream transcriptional inducer of GALNT6 in ccRCC.","method":"Immunoprecipitation coupled with LC-MS/MS; VVA lectin blot; site-directed mutagenesis (Ser161Ala); gain/loss-of-function experiments; in vivo xenograft; LEDGF overexpression/knockdown","journal":"Cancer science","confidence":"High","confidence_rationale":"Tier 1 / Strong — site-directed mutagenesis of glycosylation site combined with IP-MS substrate identification, functional assays in vitro and in vivo, single rigorous study","pmids":["39105355"],"is_preprint":false},{"year":2024,"finding":"GALNT6 O-glycosylates CCDC88C, stabilizing the protein; this stabilization enables CCDC88C to drive c-JUN-mediated CEMIP transcription and promote breast cancer metastasis.","method":"Co-immunoprecipitation; VVA lectin blot; GALNT6 knockdown/overexpression; CCDC88C stability assay; in vitro and in vivo metastasis assays","journal":"Cancer cell international","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus lectin blot for glycosylation and stability functional assay, single lab","pmids":["38971758"],"is_preprint":false},{"year":2024,"finding":"GALNT6 O-glycosylates LAPTM5, and this modification is required for LAPTM5 activity and autophagy promotion; GALNT6 also maintains the PDGFA–PDGFRB axis required for cancer-associated fibroblast activation and SPP1 secretion, contributing to lenvatinib resistance in HCC.","method":"VVA lectin assay; siRNA knockdown; Western blot; in vitro and in vivo lenvatinib sensitivity assays; TCGA-LIHC immune infiltration analysis","journal":"Cellular oncology (Dordrecht, Netherlands)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — lectin-based glycosylation detection plus functional KD in vitro and in vivo, single lab","pmids":["39718738"],"is_preprint":false},{"year":2024,"finding":"GALNT6 O-glycosylates EFEMP1, slowing its proteasomal degradation and thereby increasing EFEMP1 protein levels; KLF9 transcription factor binds the GALNT6 promoter to suppress its transcription, placing KLF9 upstream of GALNT6 in osteosarcoma.","method":"Label-free proteomics; co-immunoprecipitation/MS; VVA lectin-based O-glycosylation assay; GALNT6 overexpression/knockdown; EFEMP1 knockdown rescue; KLF9 ChIP/promoter binding","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — proteomics-MS substrate identification with functional glycosylation and stability assays, single lab","pmids":["39581475"],"is_preprint":false},{"year":2025,"finding":"GALNT6 O-glycosylates GRP78/BiP specifically at Thr203 in the Golgi apparatus (under ER stress GRP78 is transported from ER to Golgi where GALNT6 resides); substitution of Thr203 with alanine inhibits GRP78 binding to the ER stress sensor IRE1, indicating that Thr203 O-glycosylation is required for sustained UPR/IRE1 activation.","method":"Site-directed mutagenesis (Thr203Ala); co-immunoprecipitation of GRP78 with IRE1; immunofluorescence for subcellular localization under ER stress; cell proliferation assay with GALNT6 or GRP78 functional inhibition","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — site-directed mutagenesis at defined glycosylation site combined with co-IP demonstrating abrogated IRE1 binding and functional localization data, multiple orthogonal methods in one study","pmids":["41197411"],"is_preprint":false},{"year":2025,"finding":"GALNT6 O-glycosylates and stabilizes HIF-1α, PFKM, and PKM2 (protecting them from proteasomal degradation) to promote glycolysis; simultaneously GALNT6 upregulates IDH2 and α-KGDH while suppressing GPT2, depleting α-ketoglutarate and inhibiting TET3-mediated DNA demethylation, raising 5mC levels and activating pro-tumorigenic genes such as KIF14 in TNBC.","method":"GALNT6 knockdown; glycolytic activity measurement; metabolite quantification; protein stability assays; transcriptional analysis; DNA methylation (5mC) measurement","journal":"Biochimica et biophysica acta. Molecular basis of disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple substrates and pathways probed by KD with metabolomics and epigenetic readouts, single lab, no in vitro reconstitution","pmids":["42173327"],"is_preprint":false},{"year":2025,"finding":"GALNT6-mediated glycosylation blocks STING translocation and accelerates its degradation (in a cGAS-independent manner), reducing IFN-β, CCL5, and CXCL10 production; additionally, GALNT6 stabilizes PD-L1 by blocking its ubiquitin-proteasome degradation, promoting immune evasion in PDAC.","method":"siRNA knockdown; Western blot for STING, PD-L1, IFN-β; immunofluorescence for STING localization; cytokine ELISA; T cell/macrophage co-culture sensitivity assays","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — localization and degradation assays for two substrates with functional immune co-culture readout, single lab","pmids":["40541816"],"is_preprint":false}],"current_model":"GALNT6 is a Golgi-resident UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase that catalyzes the first step of mucin-type O-glycosylation on diverse substrates—including MUC1, MUC4, EGFR, APP, GRP78/BiP (at Thr203), ERα (at Ser573), LGALS3BP, α2M, CCDC88C, PHB2, EFEMP1, HIF-1α, PFKM, PKM2, STING, and PD-L1—thereby modulating their stability, subcellular localization, and signaling activity, with downstream effects on ER stress/UPR, Wnt/β-catenin, EGFR/MAPK, PI3K/Akt, NF-κB/NLRP3, glycolytic-epigenetic reprogramming, and immune evasion pathways in multiple cancer contexts."},"narrative":{"mechanistic_narrative":"GALNT6 is a Golgi-resident UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase that initiates mucin-type O-glycosylation by transferring GalNAc to serine/threonine residues of acceptor peptides, with a substrate specificity that overlaps but is functionally distinct from the closely related GALNT3 [PMID:10464263, PMID:29187600]. Its glycosylation activity broadly controls the stability, localization, secretion, and signaling output of its protein substrates: it stabilizes and retains the ER chaperone GRP78/BiP (glycosylating Thr203 in the Golgi under ER stress to sustain IRE1-dependent UPR signaling) [PMID:28110670, PMID:41197411], stabilizes and confers nuclear localization on estrogen receptor alpha through site-specific glycosylation at Ser573 [PMID:30208353], and is required for the secretion and autocrine growth activity of LGALS3BP via glycosylation at Thr556/Thr571/Ser582 [PMID:31894262]. Through these and related substrate modifications, GALNT6 drives oncogenic programs in multiple cancers—supporting MUC4/HER2 and MUC1/β-catenin signaling, EGFR phosphorylation, and PI3K/Akt and MEK–ERK activation—thereby promoting proliferation, invasion, epithelial-mesenchymal transition, and metastasis [PMID:28388560, PMID:27237318, PMID:30662357, PMID:32393740]. In normal colon epithelium its de novo expression is sufficient to elicit dysplastic growth and disrupt differentiation and cell-cell adhesion [PMID:29187600]. Beyond cancer, GALNT6 glycosylates amyloid precursor protein and reduces amyloid-β production by sterically hindering secretase cleavage [PMID:28053144].","teleology":[{"year":1999,"claim":"Established GALNT6 as a bona fide polypeptide GalNAc-transferase, defining the enzymatic activity and showing it is not fully redundant with the highly similar GALNT3.","evidence":"In vitro enzymatic assays with defined acceptor peptides plus genomic cloning and expression analysis","pmids":["10464263"],"confidence":"High","gaps":["Physiological substrates in vivo not identified","No structural basis for substrate selectivity vs GALNT3"]},{"year":2016,"claim":"Linked GALNT6 activity to amyloid biology by showing direct O-glycosylation of APP suppresses Aβ production, indicating glycosylation can sterically gate secretase processing.","evidence":"GALNT6 transfection in HEK293T, in vitro GalNAc-T assay on soluble APP, Aβ ELISA and secretase activity assays","pmids":["28053144"],"confidence":"Medium","gaps":["Glycosylation site on APP not mapped","Relevance in neuronal cells/in vivo untested"]},{"year":2016,"claim":"Connected GALNT6 to mucin substrate stability by showing it is required for MUC4 protein/transcript levels and downstream HER2/ERK and mesenchymal phenotype.","evidence":"siRNA knockdown in pancreatic cancer cells with Western blot, RT-PCR, viability and cadherin-switching readouts","pmids":["27237318"],"confidence":"Medium","gaps":["Direct glycosylation of MUC4 not biochemically demonstrated here","Mechanism of transcript-level change unresolved"]},{"year":2017,"claim":"Showed GALNT6 promotes EGFR signaling via O-glycosylation, establishing a receptor tyrosine kinase as a functional substrate-coupled output.","evidence":"VVA lectin pull-down of EGFR, siRNA knockdown, phospho-RTK array, and rescue with erlotinib in ovarian cancer cells","pmids":["28388560"],"confidence":"Medium","gaps":["EGFR glycosylation sites not mapped","Single lab, no in vivo confirmation"]},{"year":2017,"claim":"Identified GRP78/BiP as a GALNT6 substrate and revealed a reciprocal localization loop, tying GALNT6 to ER chaperone stability and anti-apoptotic function.","evidence":"VVA lectin pull-down with mass spectrometry, co-IP, immunofluorescence localization, knockdown/overexpression apoptosis assays","pmids":["28110670"],"confidence":"High","gaps":["Glycosylation site not defined in this study","Mechanism of Golgi-to-ER GALNT6 relocation unclear"]},{"year":2017,"claim":"Demonstrated causal oncogenic sufficiency: de novo GALNT6 drives dysplasia while isogenic knockout restores differentiation, and defined a GALNT6-unique substrate repertoire distinct from GALNT3.","evidence":"CRISPR knockout/rescue in isogenic colon cancer lines with quantitative O-glycoproteomics and differentiation/proliferation/adhesion assays","pmids":["29187600"],"confidence":"High","gaps":["Which specific substrate(s) drive the dysplastic phenotype not isolated","In vivo tumorigenesis not addressed"]},{"year":2018,"claim":"Mapped a site-specific glycosylation event (ERα Ser573) controlling ERα stability and nuclear localization, linking GALNT6 to hormone-receptor signaling in breast cancer.","evidence":"LC-MS/MS site identification, siRNA knockdown, immunocytochemistry, co-IP, peptide competition with ERα target-gene readout","pmids":["30208353"],"confidence":"High","gaps":["Structural mechanism by which Ser573 glycosylation governs nuclear import unknown","In vivo relevance to endocrine therapy untested here"]},{"year":2019,"claim":"Established that GALNT6 glycosylation at three defined sites is required for LGALS3BP secretion and autocrine growth, demonstrating mechanistic causality by mutagenesis.","evidence":"VVA pull-down, site-directed mutagenesis (T556A/T571A/S582A), secretion and proliferation assays in breast cancer cells","pmids":["31894262"],"confidence":"High","gaps":["Receptor mediating LGALS3BP autocrine signaling not defined","In vivo confirmation absent"]},{"year":2019,"claim":"Extended GALNT6 oncogenicity to the β-catenin/MUC1-C axis through physical interaction with MUC1-N driving nuclear β-catenin and proliferative targets.","evidence":"Co-IP (GALNT6–MUC1-N; β-catenin–MUC1-C), cell fractionation, siRNA knockdown and Western blot","pmids":["30662357"],"confidence":"Medium","gaps":["Direct glycosylation event not site-mapped","Co-IP not reciprocally validated for direct binding"]},{"year":2020,"claim":"Showed GALNT6 glycosylation of secreted α2M and chaperone GRP78 funnels into PI3K/Akt and MEK–ERK signaling to promote migration, invasion and EMT across cancer types.","evidence":"Glycosylomics/VVA blots, co-IP, knockdown/overexpression with PI3K/Akt and MEK/ERK Westerns and xenograft metastasis assay","pmids":["32559179","32393740"],"confidence":"Medium","gaps":["Glycosylation sites on α2M and GRP78 not mapped in these studies","Single-lab functional readouts"]},{"year":2022,"claim":"Placed GALNT6 within a transcriptional circuit (RUNX3-driven) feeding MUC1 stabilization, linking upstream regulation to substrate-level output in HCC.","evidence":"Promoter binding/ChIP, RT-qPCR, knockdown and MUC1 rescue in hepatocellular carcinoma cells","pmids":["35909886"],"confidence":"Medium","gaps":["MUC1 glycosylation site not defined","Generality of RUNX3 regulation across tissues unknown"]},{"year":2024,"claim":"Identified additional site-specific (PHB2 Ser161) and stabilizing substrate modifications (CCDC88C, EFEMP1) and their upstream transcriptional regulators, broadening GALNT6's substrate-stabilization paradigm.","evidence":"IP-MS, VVA lectin blots, site-directed mutagenesis (S161A), stability and metastasis assays in vitro/in vivo; LEDGF and KLF9 promoter studies","pmids":["39105355","38971758","39581475"],"confidence":"Medium","gaps":["Whether stabilization is direct glycosylation-dependent for CCDC88C/EFEMP1 not site-resolved","Tissue specificity of upstream regulators unclear"]},{"year":2025,"claim":"Refined the GRP78 mechanism by mapping Thr203 glycosylation in the Golgi as required for GRP78–IRE1 binding and sustained UPR signaling.","evidence":"Site-directed mutagenesis (T203A), co-IP of GRP78 with IRE1, localization imaging under ER stress and proliferation assays","pmids":["41197411"],"confidence":"High","gaps":["How Thr203 glycosylation structurally promotes IRE1 engagement unknown","Effect on PERK/ATF6 arms of UPR not assessed"]},{"year":2025,"claim":"Expanded GALNT6 function into metabolic-epigenetic reprogramming and immune evasion by stabilizing glycolytic enzymes/HIF-1α and modulating STING/PD-L1.","evidence":"Knockdown with glycolytic/metabolite/5mC measurements; STING and PD-L1 localization/degradation assays with immune co-culture","pmids":["42173327","40541816"],"confidence":"Medium","gaps":["Glycosylation sites on metabolic and immune substrates not mapped","No in vitro reconstitution of these modifications"]},{"year":null,"claim":"How GALNT6 selects its broad substrate repertoire and how individual site-specific glycosylations mechanistically alter substrate folding, trafficking, and degradation remain largely unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of substrate recognition","Most reported substrates lack mapped glycosylation sites","In vivo physiological (non-cancer) roles minimally characterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,2,5,6,7,13,17]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,4,6,7,13,17]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[4,17]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[4,17]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,4,6,7,17]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,8,9,10]},{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[4,17]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[3,5,8,18,19]}],"complexes":[],"partners":["HSPA5","ERN1","MUC1","EGFR","ESR1","LGALS3BP","PHB2","CCDC88C"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8NCL4","full_name":"Polypeptide N-acetylgalactosaminyltransferase 6","aliases":["Polypeptide GalNAc transferase 6","GalNAc-T6","pp-GaNTase 6","Protein-UDP acetylgalactosaminyltransferase 6","UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 6"],"length_aa":622,"mass_kda":71.2,"function":"Catalyzes the initial reaction in O-linked oligosaccharide biosynthesis, the transfer of an N-acetyl-D-galactosamine residue to a serine or threonine residue on the protein receptor (PubMed:10464263, PubMed:31932717). May participate in synthesis of oncofetal fibronectin (PubMed:10464263). Has activity toward MUC1A, MUC2, EA2 and fibronectin peptides (PubMed:10464263). Glycosylates FGF23 (PubMed:31932717)","subcellular_location":"Golgi apparatus membrane","url":"https://www.uniprot.org/uniprotkb/Q8NCL4/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GALNT6","classification":"Not Classified","n_dependent_lines":10,"n_total_lines":1208,"dependency_fraction":0.008278145695364239},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/GALNT6","total_profiled":1310},"omim":[{"mim_id":"605148","title":"UDP-N-ACETYL-ALPHA-D-GALACTOSAMINE:POLYPEPTIDE N-ACETYLGALACTOSAMINYLTRANSFERASE 6; GALNT6","url":"https://www.omim.org/entry/605148"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Golgi apparatus","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"cervix","ntpm":30.2},{"tissue":"stomach 1","ntpm":59.0}],"url":"https://www.proteinatlas.org/search/GALNT6"},"hgnc":{"alias_symbol":["GalNAc-T6"],"prev_symbol":[]},"alphafold":{"accession":"Q8NCL4","domains":[{"cath_id":"3.90.550.10","chopping":"115-409","consensus_level":"high","plddt":96.6883,"start":115,"end":409},{"cath_id":"1.10.8.460","chopping":"427-485","consensus_level":"medium","plddt":96.8119,"start":427,"end":485},{"cath_id":"2.80.10.50","chopping":"498-622","consensus_level":"high","plddt":93.2673,"start":498,"end":622}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NCL4","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NCL4-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NCL4-F1-predicted_aligned_error_v6.png","plddt_mean":88.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GALNT6","jax_strain_url":"https://www.jax.org/strain/search?query=GALNT6"},"sequence":{"accession":"Q8NCL4","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8NCL4.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8NCL4/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NCL4"}},"corpus_meta":[{"pmid":"10464263","id":"PMC_10464263","title":"Cloning and characterization of a close homologue of human UDP-N-acetyl-alpha-D-galactosamine:Polypeptide N-acetylgalactosaminyltransferase-T3, designated GalNAc-T6. Evidence for genetic but not functional redundancy.","date":"1999","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10464263","citation_count":162,"is_preprint":false},{"pmid":"29187600","id":"PMC_29187600","title":"De novo expression of human polypeptide N-acetylgalactosaminyltransferase 6 (GalNAc-T6) in colon adenocarcinoma inhibits the differentiation of colonic epithelium.","date":"2017","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29187600","citation_count":62,"is_preprint":false},{"pmid":"28388560","id":"PMC_28388560","title":"GALNT6 expression enhances aggressive phenotypes of ovarian cancer cells by regulating EGFR activity.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/28388560","citation_count":40,"is_preprint":false},{"pmid":"28053144","id":"PMC_28053144","title":"Excess APP O-glycosylation by GalNAc-T6 decreases Aβ production.","date":"2016","source":"Journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/28053144","citation_count":40,"is_preprint":false},{"pmid":"27237318","id":"PMC_27237318","title":"Morphological Changes, Cadherin Switching, and Growth Suppression in Pancreatic Cancer by GALNT6 Knockdown.","date":"2016","source":"Neoplasia (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/27237318","citation_count":39,"is_preprint":false},{"pmid":"32559179","id":"PMC_32559179","title":"GALNT6 promotes breast cancer metastasis by increasing mucin-type O-glycosylation of α2M.","date":"2020","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/32559179","citation_count":38,"is_preprint":false},{"pmid":"32393740","id":"PMC_32393740","title":"GALNT6 promotes invasion and metastasis of human lung adenocarcinoma cells through O-glycosylating chaperone protein GRP78.","date":"2020","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/32393740","citation_count":35,"is_preprint":false},{"pmid":"28110670","id":"PMC_28110670","title":"GALNT6 Stabilizes GRP78 Protein by O-glycosylation and Enhances its Activity to Suppress Apoptosis Under Stress Condition.","date":"2017","source":"Neoplasia (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/28110670","citation_count":33,"is_preprint":false},{"pmid":"30662357","id":"PMC_30662357","title":"GALNT6 Promotes Tumorigenicity and Metastasis of Breast Cancer Cell via β-catenin/MUC1-C Signaling Pathway.","date":"2019","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/30662357","citation_count":30,"is_preprint":false},{"pmid":"31894262","id":"PMC_31894262","title":"The GALNT6‑LGALS3BP axis promotes breast cancer cell growth.","date":"2019","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/31894262","citation_count":24,"is_preprint":false},{"pmid":"31071912","id":"PMC_31071912","title":"The polypeptide GALNT6 Displays Redundant Functions upon Suppression of its Closest Homolog GALNT3 in Mediating Aberrant O-Glycosylation, Associated with Ovarian Cancer Progression.","date":"2019","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/31071912","citation_count":20,"is_preprint":false},{"pmid":"30662801","id":"PMC_30662801","title":"GALNT6 suppresses progression of colorectal cancer.","date":"2018","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/30662801","citation_count":19,"is_preprint":false},{"pmid":"30208353","id":"PMC_30208353","title":"Critical Role of Estrogen Receptor Alpha O-Glycosylation by N-Acetylgalactosaminyltransferase 6 (GALNT6) in Its Nuclear Localization in Breast Cancer Cells.","date":"2018","source":"Neoplasia (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/30208353","citation_count":19,"is_preprint":false},{"pmid":"39245709","id":"PMC_39245709","title":"GALNT6 promotes bladder cancer malignancy and immune escape by epithelial-mesenchymal transition and CD8+ T cells.","date":"2024","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/39245709","citation_count":15,"is_preprint":false},{"pmid":"36925932","id":"PMC_36925932","title":"Knocking down GALNT6 promotes pyroptosis of pancreatic ductal adenocarcinoma cells through NF-κB/NLRP3/GSDMD and GSDME signaling pathway.","date":"2023","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/36925932","citation_count":14,"is_preprint":false},{"pmid":"39718738","id":"PMC_39718738","title":"GALNT6 drives lenvatinib resistance in hepatocellular carcinoma through autophagy and cancer-associated fibroblast activation.","date":"2024","source":"Cellular oncology (Dordrecht, Netherlands)","url":"https://pubmed.ncbi.nlm.nih.gov/39718738","citation_count":10,"is_preprint":false},{"pmid":"27659430","id":"PMC_27659430","title":"UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase- 6 (pp-GalNAc-T6): Role in Cancer and Prospects as a Drug Target.","date":"2017","source":"Current cancer drug targets","url":"https://pubmed.ncbi.nlm.nih.gov/27659430","citation_count":10,"is_preprint":false},{"pmid":"40541816","id":"PMC_40541816","title":"GALNT6 dual regulates innate immunity STING signaling and PD-L1 expression to promote immune evasion in pancreatic ductal adenocarcinoma.","date":"2025","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/40541816","citation_count":7,"is_preprint":false},{"pmid":"39105355","id":"PMC_39105355","title":"N-acetylgalactosaminyltransferase GALNT6 is a potential therapeutic target of clear cell renal cell carcinoma progression.","date":"2024","source":"Cancer science","url":"https://pubmed.ncbi.nlm.nih.gov/39105355","citation_count":6,"is_preprint":false},{"pmid":"35909886","id":"PMC_35909886","title":"RUNX3-Regulated GALNT6 Promotes the Migration and Invasion of Hepatocellular Carcinoma Cells by Mediating O-Glycosylation of MUC1.","date":"2022","source":"Disease markers","url":"https://pubmed.ncbi.nlm.nih.gov/35909886","citation_count":5,"is_preprint":false},{"pmid":"38971758","id":"PMC_38971758","title":"CCDC88C, an O-GalNAc glycosylation substrate of GALNT6, drives breast cancer metastasis by promoting c-JUN-mediated CEMIP transcription.","date":"2024","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/38971758","citation_count":5,"is_preprint":false},{"pmid":"35003361","id":"PMC_35003361","title":"GALNT6 Knockdown Inhibits the Proliferation and Migration of Colorectal Cancer Cells and Increases the Sensitivity of Cancer Cells to 5-FU.","date":"2021","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/35003361","citation_count":3,"is_preprint":false},{"pmid":"41197411","id":"PMC_41197411","title":"Crucial roles of GALNT6-mediated O-glycosylation of GRP78/Bip in proliferation of breast cancer cells.","date":"2025","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/41197411","citation_count":1,"is_preprint":false},{"pmid":"38889447","id":"PMC_38889447","title":"GALNT6, GALNT14, and Gal-3 in association with GDF-15 promotes drug resistance and stemness of breast cancer via β-catenin axis.","date":"2024","source":"Growth factors (Chur, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/38889447","citation_count":1,"is_preprint":false},{"pmid":"40659945","id":"PMC_40659945","title":"GALNT6 associated with O-GlcNAcylation contributes to the tumorigenesis of oral squamous cell carcinoma.","date":"2025","source":"Discover oncology","url":"https://pubmed.ncbi.nlm.nih.gov/40659945","citation_count":1,"is_preprint":false},{"pmid":"39581475","id":"PMC_39581475","title":"GALNT6, transcriptionally inhibited by KLF9, promotes osteosarcoma progression by increasing EFEMP1 expression via O-glycosylation modification.","date":"2024","source":"Biochimica et biophysica acta. Molecular cell research","url":"https://pubmed.ncbi.nlm.nih.gov/39581475","citation_count":1,"is_preprint":false},{"pmid":"40741237","id":"PMC_40741237","title":"Downregulation of circ_0119412 expression inhibits malignant progression of breast cancer by targeting the miR-1205/GALNT6 pathway in vivo and in vitro.","date":"2024","source":"Archives of medical science : AMS","url":"https://pubmed.ncbi.nlm.nih.gov/40741237","citation_count":1,"is_preprint":false},{"pmid":"34803515","id":"PMC_34803515","title":"Erratum: GALNT6 Promotes Tumorigenicity and Metastasis of Breast Cancer Cell via β-catenin/MUC1-C Signaling Pathway: Erratum.","date":"2021","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/34803515","citation_count":1,"is_preprint":false},{"pmid":"42173327","id":"PMC_42173327","title":"GALNT6 coordinates glycolysis and α-KG-dependent DNA methylation to promote TNBC progression.","date":"2026","source":"Biochimica et biophysica acta. Molecular basis of disease","url":"https://pubmed.ncbi.nlm.nih.gov/42173327","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":17015,"output_tokens":5263,"usd":0.064995,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":13522,"output_tokens":4532,"usd":0.090455,"stage2_stop_reason":"end_turn"},"total_usd":0.15545,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"GALNT6 (GalNAc-T6) encodes a UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase that catalyzes O-GalNAc transfer to peptide substrates; its acceptor substrate specificities overlap with but are distinct from other GalNAc-transferases, and despite high sequence similarity to GALNT3 the two enzymes do not provide full functional redundancy.\",\n      \"method\": \"In vitro enzymatic activity assays with defined acceptor peptides; Northern analysis; immunocytology with monoclonal antibodies; genomic cloning and sequence analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in vitro enzymatic assay with defined substrates, replicated across multiple orthogonal methods in founding characterization paper\",\n      \"pmids\": [\"10464263\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"GALNT6 O-glycosylates EGFR, increasing EGFR phosphorylation and downstream signaling in ovarian cancer cells; GALNT6 knockdown reduced EGFR phosphorylation and the enhanced invasive behavior was reversed by the EGFR inhibitor erlotinib.\",\n      \"method\": \"siRNA knockdown; phospho-RTK array; Western blot; VVA lectin pull-down assay to detect O-GalNAc modification of EGFR; GALNT6 overexpression\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — lectin pulldown plus functional rescue with pharmacological EGFR inhibitor, single lab with two orthogonal methods\",\n      \"pmids\": [\"28388560\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GALNT6 directly O-glycosylates amyloid precursor protein (APP), and excess O-glycosylation of APP by GALNT6 reduces both Aβ1-40 and Aβ1-42 production without significantly altering α- or β-secretase activities, suggesting steric hindrance of secretase cleavage.\",\n      \"method\": \"Transfection of GALNT6 into HEK293T cells; in vitro GalNAc-T enzymatic activity assay on soluble APP; ELISA for Aβ; secretase activity assays\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro enzymatic assay on APP substrate, single lab with multiple readouts\",\n      \"pmids\": [\"28053144\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GALNT6 knockdown in pancreatic cancer cells decreased MUC4 protein and transcript levels, reduced HER2 and ERK levels, suppressed viability, and caused cadherin switching from P-cadherin to E-cadherin, indicating GALNT6 O-glycosylation activity is required for MUC4 stability and maintenance of a mesenchymal phenotype.\",\n      \"method\": \"siRNA knockdown; Western blot; RT-PCR; cell viability assay; immunofluorescence for cadherin switching\",\n      \"journal\": \"Neoplasia (New York, N.Y.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KD with defined molecular and phenotypic readouts, single lab\",\n      \"pmids\": [\"27237318\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"GALNT6 O-glycosylates GRP78 (HSPA5/BiP); this O-glycosylation stabilizes GRP78 protein, retains it in the ER, and enhances its anti-apoptotic function. Conversely, overexpression of GRP78 promotes Golgi-to-ER relocation of GALNT6, indicating a reciprocal regulatory loop.\",\n      \"method\": \"VVA lectin pull-down followed by mass spectrometry to identify GRP78 as GALNT6 substrate; co-immunoprecipitation; Western blot; immunofluorescence for subcellular localization; GALNT6 knockdown/overexpression with apoptosis readout\",\n      \"journal\": \"Neoplasia (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — lectin pulldown-MS substrate identification plus functional validation (localization, stability, apoptosis) in a single lab with multiple orthogonal methods\",\n      \"pmids\": [\"28110670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"De novo expression of GALNT6 in colon cancer cells drives a cancer-like dysplastic growth pattern; GALNT6 knockout restores more normal differentiation, reduces proliferation, and normalizes cell-cell adhesion. O-glycoproteomic analysis identified a specific set of GALNT6-unique substrates distinct from those of the closely related GALNT3.\",\n      \"method\": \"Precise gene targeting (CRISPR-based) knockout/rescue in isogenic cell lines; O-glycoproteomics; tissue culture differentiation assay; proliferation assay; cell-cell adhesion assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — isogenic KO/rescue system combined with quantitative O-glycoproteomics and multiple orthogonal functional assays\",\n      \"pmids\": [\"29187600\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"GALNT6 O-glycosylates estrogen receptor alpha (ERα) at Ser573 in its F domain; this modification is required for ERα protein stability and nuclear localization in breast cancer cells. GALNT6 knockdown reduces ERα protein abundance, causes loss of nuclear ERα, and downregulates ERα target genes (MYC, CCND1, CTSD).\",\n      \"method\": \"siRNA knockdown; immunocytochemistry; LC-MS/MS identification of O-glycosylation site (Ser573); co-immunoprecipitation; cell-permeable peptide competition assay\",\n      \"journal\": \"Neoplasia (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — site-specific O-glycosylation identified by LC-MS/MS, functional validation by localization and gene expression, multiple orthogonal methods in one study\",\n      \"pmids\": [\"30208353\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GALNT6 O-glycosylates LGALS3BP at three sites (Thr556, Thr571, Ser582); this glycosylation is required for LGALS3BP secretion and its autocrine growth-promoting activity in breast cancer. Triple alanine substitution (T556A/T571A/S582A) in LGALS3BP abolished GALNT6-dependent glycosylation, secretion, and autocrine growth.\",\n      \"method\": \"siRNA knockdown; VVA lectin pull-down; site-directed mutagenesis of glycosylation sites; secretion assay; breast cancer cell proliferation assay\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — site-directed mutagenesis of glycosylation sites combined with secretion and growth assays, multiple orthogonal methods demonstrating mechanistic causality\",\n      \"pmids\": [\"31894262\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GALNT6 interacts with MUC1-N and promotes tumorigenicity and metastasis through the β-catenin/MUC1-C signaling pathway; GALNT6 knockdown reduces nuclear β-catenin and MUC1-C levels and decreases downstream targets PCNA, cyclin D1, and c-Myc while increasing E-cadherin.\",\n      \"method\": \"Co-immunoprecipitation (GALNT6 with MUC1-N; β-catenin with MUC1-C); cell fractionation assay; siRNA knockdown; Western blot\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP for binding plus cell fractionation and KD phenotype, single lab\",\n      \"pmids\": [\"30662357\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GALNT6 O-glycosylates alpha-2-macroglobulin (α2M), and this modification activates downstream PI3K/Akt signaling to promote breast cancer cell migration and invasion.\",\n      \"method\": \"Glycosylomics analysis of supernatants from breast cancer cells; VVA lectin blot; siRNA knockdown; Western blot for PI3K/Akt; migration and invasion assays\",\n      \"journal\": \"Aging\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — glycosylomics-based substrate identification plus functional assay, single lab\",\n      \"pmids\": [\"32559179\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GALNT6 directly interacts with and O-glycosylates chaperone GRP78 in lung adenocarcinoma cells; this modification promotes epithelial-mesenchymal transition by enhancing MEK1/2–ERK1/2 signaling.\",\n      \"method\": \"Co-immunoprecipitation; VVA lectin pull-down; GALNT6 overexpression/silencing; Western blot for MEK/ERK; in vivo xenograft metastasis assay\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP and lectin pulldown with downstream signaling readout, single lab\",\n      \"pmids\": [\"32393740\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"RUNX3 transcription factor binds the GALNT6 promoter and activates GALNT6 transcription; GALNT6-mediated O-glycosylation of MUC1 prevents its degradation and is required for HCC cell migration and invasion.\",\n      \"method\": \"Chromatin immunoprecipitation / promoter binding assay; RT-qPCR; Western blot; siRNA knockdown; MUC1 overexpression rescue experiment\",\n      \"journal\": \"Disease markers\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — promoter-binding assay identifies upstream regulator, functional rescue confirms MUC1 as effector substrate, single lab\",\n      \"pmids\": [\"35909886\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"GALNT6 suppresses pyroptosis in pancreatic ductal adenocarcinoma by O-glycosylating NF-κB, inhibiting its nuclear translocation and thereby repressing NLRP3/GSDMD expression; additionally, GALNT6 promotes proteasomal degradation of GSDME via O-glycosylation, collectively blocking pyroptotic cell death.\",\n      \"method\": \"siRNA knockdown; Western blot; immunofluorescence for NF-κB localization; ELISA for IL-1β, IL-6, TNF-α, IL-18; scanning electron microscopy for pyroptosis morphology; qRT-PCR\",\n      \"journal\": \"Frontiers in oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD with localization and proteolysis readouts for two substrates, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"36925932\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GALNT6 O-glycosylates prohibitin 2 (PHB2) at Ser161; this modification is required for GALNT6-induced ccRCC cell proliferation, migration, and invasion. LEDGF was identified as an upstream transcriptional inducer of GALNT6 in ccRCC.\",\n      \"method\": \"Immunoprecipitation coupled with LC-MS/MS; VVA lectin blot; site-directed mutagenesis (Ser161Ala); gain/loss-of-function experiments; in vivo xenograft; LEDGF overexpression/knockdown\",\n      \"journal\": \"Cancer science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — site-directed mutagenesis of glycosylation site combined with IP-MS substrate identification, functional assays in vitro and in vivo, single rigorous study\",\n      \"pmids\": [\"39105355\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GALNT6 O-glycosylates CCDC88C, stabilizing the protein; this stabilization enables CCDC88C to drive c-JUN-mediated CEMIP transcription and promote breast cancer metastasis.\",\n      \"method\": \"Co-immunoprecipitation; VVA lectin blot; GALNT6 knockdown/overexpression; CCDC88C stability assay; in vitro and in vivo metastasis assays\",\n      \"journal\": \"Cancer cell international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus lectin blot for glycosylation and stability functional assay, single lab\",\n      \"pmids\": [\"38971758\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GALNT6 O-glycosylates LAPTM5, and this modification is required for LAPTM5 activity and autophagy promotion; GALNT6 also maintains the PDGFA–PDGFRB axis required for cancer-associated fibroblast activation and SPP1 secretion, contributing to lenvatinib resistance in HCC.\",\n      \"method\": \"VVA lectin assay; siRNA knockdown; Western blot; in vitro and in vivo lenvatinib sensitivity assays; TCGA-LIHC immune infiltration analysis\",\n      \"journal\": \"Cellular oncology (Dordrecht, Netherlands)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — lectin-based glycosylation detection plus functional KD in vitro and in vivo, single lab\",\n      \"pmids\": [\"39718738\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GALNT6 O-glycosylates EFEMP1, slowing its proteasomal degradation and thereby increasing EFEMP1 protein levels; KLF9 transcription factor binds the GALNT6 promoter to suppress its transcription, placing KLF9 upstream of GALNT6 in osteosarcoma.\",\n      \"method\": \"Label-free proteomics; co-immunoprecipitation/MS; VVA lectin-based O-glycosylation assay; GALNT6 overexpression/knockdown; EFEMP1 knockdown rescue; KLF9 ChIP/promoter binding\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — proteomics-MS substrate identification with functional glycosylation and stability assays, single lab\",\n      \"pmids\": [\"39581475\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"GALNT6 O-glycosylates GRP78/BiP specifically at Thr203 in the Golgi apparatus (under ER stress GRP78 is transported from ER to Golgi where GALNT6 resides); substitution of Thr203 with alanine inhibits GRP78 binding to the ER stress sensor IRE1, indicating that Thr203 O-glycosylation is required for sustained UPR/IRE1 activation.\",\n      \"method\": \"Site-directed mutagenesis (Thr203Ala); co-immunoprecipitation of GRP78 with IRE1; immunofluorescence for subcellular localization under ER stress; cell proliferation assay with GALNT6 or GRP78 functional inhibition\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — site-directed mutagenesis at defined glycosylation site combined with co-IP demonstrating abrogated IRE1 binding and functional localization data, multiple orthogonal methods in one study\",\n      \"pmids\": [\"41197411\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"GALNT6 O-glycosylates and stabilizes HIF-1α, PFKM, and PKM2 (protecting them from proteasomal degradation) to promote glycolysis; simultaneously GALNT6 upregulates IDH2 and α-KGDH while suppressing GPT2, depleting α-ketoglutarate and inhibiting TET3-mediated DNA demethylation, raising 5mC levels and activating pro-tumorigenic genes such as KIF14 in TNBC.\",\n      \"method\": \"GALNT6 knockdown; glycolytic activity measurement; metabolite quantification; protein stability assays; transcriptional analysis; DNA methylation (5mC) measurement\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular basis of disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple substrates and pathways probed by KD with metabolomics and epigenetic readouts, single lab, no in vitro reconstitution\",\n      \"pmids\": [\"42173327\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"GALNT6-mediated glycosylation blocks STING translocation and accelerates its degradation (in a cGAS-independent manner), reducing IFN-β, CCL5, and CXCL10 production; additionally, GALNT6 stabilizes PD-L1 by blocking its ubiquitin-proteasome degradation, promoting immune evasion in PDAC.\",\n      \"method\": \"siRNA knockdown; Western blot for STING, PD-L1, IFN-β; immunofluorescence for STING localization; cytokine ELISA; T cell/macrophage co-culture sensitivity assays\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — localization and degradation assays for two substrates with functional immune co-culture readout, single lab\",\n      \"pmids\": [\"40541816\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GALNT6 is a Golgi-resident UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase that catalyzes the first step of mucin-type O-glycosylation on diverse substrates—including MUC1, MUC4, EGFR, APP, GRP78/BiP (at Thr203), ERα (at Ser573), LGALS3BP, α2M, CCDC88C, PHB2, EFEMP1, HIF-1α, PFKM, PKM2, STING, and PD-L1—thereby modulating their stability, subcellular localization, and signaling activity, with downstream effects on ER stress/UPR, Wnt/β-catenin, EGFR/MAPK, PI3K/Akt, NF-κB/NLRP3, glycolytic-epigenetic reprogramming, and immune evasion pathways in multiple cancer contexts.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GALNT6 is a Golgi-resident UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase that initiates mucin-type O-glycosylation by transferring GalNAc to serine/threonine residues of acceptor peptides, with a substrate specificity that overlaps but is functionally distinct from the closely related GALNT3 [#0, #5]. Its glycosylation activity broadly controls the stability, localization, secretion, and signaling output of its protein substrates: it stabilizes and retains the ER chaperone GRP78/BiP (glycosylating Thr203 in the Golgi under ER stress to sustain IRE1-dependent UPR signaling) [#4, #17], stabilizes and confers nuclear localization on estrogen receptor alpha through site-specific glycosylation at Ser573 [#6], and is required for the secretion and autocrine growth activity of LGALS3BP via glycosylation at Thr556/Thr571/Ser582 [#7]. Through these and related substrate modifications, GALNT6 drives oncogenic programs in multiple cancers\\u2014supporting MUC4/HER2 and MUC1/\\u03b2-catenin signaling, EGFR phosphorylation, and PI3K/Akt and MEK\\u2013ERK activation\\u2014thereby promoting proliferation, invasion, epithelial-mesenchymal transition, and metastasis [#1, #3, #8, #10]. In normal colon epithelium its de novo expression is sufficient to elicit dysplastic growth and disrupt differentiation and cell-cell adhesion [#5]. Beyond cancer, GALNT6 glycosylates amyloid precursor protein and reduces amyloid-\\u03b2 production by sterically hindering secretase cleavage [#2].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Established GALNT6 as a bona fide polypeptide GalNAc-transferase, defining the enzymatic activity and showing it is not fully redundant with the highly similar GALNT3.\",\n      \"evidence\": \"In vitro enzymatic assays with defined acceptor peptides plus genomic cloning and expression analysis\",\n      \"pmids\": [\"10464263\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological substrates in vivo not identified\", \"No structural basis for substrate selectivity vs GALNT3\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Linked GALNT6 activity to amyloid biology by showing direct O-glycosylation of APP suppresses A\\u03b2 production, indicating glycosylation can sterically gate secretase processing.\",\n      \"evidence\": \"GALNT6 transfection in HEK293T, in vitro GalNAc-T assay on soluble APP, A\\u03b2 ELISA and secretase activity assays\",\n      \"pmids\": [\"28053144\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Glycosylation site on APP not mapped\", \"Relevance in neuronal cells/in vivo untested\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Connected GALNT6 to mucin substrate stability by showing it is required for MUC4 protein/transcript levels and downstream HER2/ERK and mesenchymal phenotype.\",\n      \"evidence\": \"siRNA knockdown in pancreatic cancer cells with Western blot, RT-PCR, viability and cadherin-switching readouts\",\n      \"pmids\": [\"27237318\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct glycosylation of MUC4 not biochemically demonstrated here\", \"Mechanism of transcript-level change unresolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showed GALNT6 promotes EGFR signaling via O-glycosylation, establishing a receptor tyrosine kinase as a functional substrate-coupled output.\",\n      \"evidence\": \"VVA lectin pull-down of EGFR, siRNA knockdown, phospho-RTK array, and rescue with erlotinib in ovarian cancer cells\",\n      \"pmids\": [\"28388560\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"EGFR glycosylation sites not mapped\", \"Single lab, no in vivo confirmation\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified GRP78/BiP as a GALNT6 substrate and revealed a reciprocal localization loop, tying GALNT6 to ER chaperone stability and anti-apoptotic function.\",\n      \"evidence\": \"VVA lectin pull-down with mass spectrometry, co-IP, immunofluorescence localization, knockdown/overexpression apoptosis assays\",\n      \"pmids\": [\"28110670\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Glycosylation site not defined in this study\", \"Mechanism of Golgi-to-ER GALNT6 relocation unclear\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrated causal oncogenic sufficiency: de novo GALNT6 drives dysplasia while isogenic knockout restores differentiation, and defined a GALNT6-unique substrate repertoire distinct from GALNT3.\",\n      \"evidence\": \"CRISPR knockout/rescue in isogenic colon cancer lines with quantitative O-glycoproteomics and differentiation/proliferation/adhesion assays\",\n      \"pmids\": [\"29187600\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which specific substrate(s) drive the dysplastic phenotype not isolated\", \"In vivo tumorigenesis not addressed\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Mapped a site-specific glycosylation event (ER\\u03b1 Ser573) controlling ER\\u03b1 stability and nuclear localization, linking GALNT6 to hormone-receptor signaling in breast cancer.\",\n      \"evidence\": \"LC-MS/MS site identification, siRNA knockdown, immunocytochemistry, co-IP, peptide competition with ER\\u03b1 target-gene readout\",\n      \"pmids\": [\"30208353\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural mechanism by which Ser573 glycosylation governs nuclear import unknown\", \"In vivo relevance to endocrine therapy untested here\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Established that GALNT6 glycosylation at three defined sites is required for LGALS3BP secretion and autocrine growth, demonstrating mechanistic causality by mutagenesis.\",\n      \"evidence\": \"VVA pull-down, site-directed mutagenesis (T556A/T571A/S582A), secretion and proliferation assays in breast cancer cells\",\n      \"pmids\": [\"31894262\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Receptor mediating LGALS3BP autocrine signaling not defined\", \"In vivo confirmation absent\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended GALNT6 oncogenicity to the \\u03b2-catenin/MUC1-C axis through physical interaction with MUC1-N driving nuclear \\u03b2-catenin and proliferative targets.\",\n      \"evidence\": \"Co-IP (GALNT6\\u2013MUC1-N; \\u03b2-catenin\\u2013MUC1-C), cell fractionation, siRNA knockdown and Western blot\",\n      \"pmids\": [\"30662357\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct glycosylation event not site-mapped\", \"Co-IP not reciprocally validated for direct binding\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed GALNT6 glycosylation of secreted \\u03b12M and chaperone GRP78 funnels into PI3K/Akt and MEK\\u2013ERK signaling to promote migration, invasion and EMT across cancer types.\",\n      \"evidence\": \"Glycosylomics/VVA blots, co-IP, knockdown/overexpression with PI3K/Akt and MEK/ERK Westerns and xenograft metastasis assay\",\n      \"pmids\": [\"32559179\", \"32393740\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Glycosylation sites on \\u03b12M and GRP78 not mapped in these studies\", \"Single-lab functional readouts\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed GALNT6 within a transcriptional circuit (RUNX3-driven) feeding MUC1 stabilization, linking upstream regulation to substrate-level output in HCC.\",\n      \"evidence\": \"Promoter binding/ChIP, RT-qPCR, knockdown and MUC1 rescue in hepatocellular carcinoma cells\",\n      \"pmids\": [\"35909886\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"MUC1 glycosylation site not defined\", \"Generality of RUNX3 regulation across tissues unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified additional site-specific (PHB2 Ser161) and stabilizing substrate modifications (CCDC88C, EFEMP1) and their upstream transcriptional regulators, broadening GALNT6's substrate-stabilization paradigm.\",\n      \"evidence\": \"IP-MS, VVA lectin blots, site-directed mutagenesis (S161A), stability and metastasis assays in vitro/in vivo; LEDGF and KLF9 promoter studies\",\n      \"pmids\": [\"39105355\", \"38971758\", \"39581475\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether stabilization is direct glycosylation-dependent for CCDC88C/EFEMP1 not site-resolved\", \"Tissue specificity of upstream regulators unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Refined the GRP78 mechanism by mapping Thr203 glycosylation in the Golgi as required for GRP78\\u2013IRE1 binding and sustained UPR signaling.\",\n      \"evidence\": \"Site-directed mutagenesis (T203A), co-IP of GRP78 with IRE1, localization imaging under ER stress and proliferation assays\",\n      \"pmids\": [\"41197411\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How Thr203 glycosylation structurally promotes IRE1 engagement unknown\", \"Effect on PERK/ATF6 arms of UPR not assessed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Expanded GALNT6 function into metabolic-epigenetic reprogramming and immune evasion by stabilizing glycolytic enzymes/HIF-1\\u03b1 and modulating STING/PD-L1.\",\n      \"evidence\": \"Knockdown with glycolytic/metabolite/5mC measurements; STING and PD-L1 localization/degradation assays with immune co-culture\",\n      \"pmids\": [\"42173327\", \"40541816\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Glycosylation sites on metabolic and immune substrates not mapped\", \"No in vitro reconstitution of these modifications\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How GALNT6 selects its broad substrate repertoire and how individual site-specific glycosylations mechanistically alter substrate folding, trafficking, and degradation remain largely unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of substrate recognition\", \"Most reported substrates lack mapped glycosylation sites\", \"In vivo physiological (non-cancer) roles minimally characterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 2, 5, 6, 7, 13, 17]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 4, 6, 7, 13, 17]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [4, 17]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [4, 17]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 4, 6, 7, 17]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 8, 9, 10]},\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [4, 17]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [3, 5, 8, 18, 19]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"HSPA5\", \"ERN1\", \"MUC1\", \"EGFR\", \"ESR1\", \"LGALS3BP\", \"PHB2\", \"CCDC88C\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":5,"faith_pct":80.0}}