{"gene":"GGCT","run_date":"2026-04-28T18:06:52","timeline":{"discoveries":[{"year":2008,"finding":"C7orf24 (GGCT) was identified as gamma-glutamyl cyclotransferase, catalyzing the formation of 5-oxoproline (pyroglutamic acid) from gamma-glutamyl dipeptides. Crystal structure at 1.7 Å resolution revealed a homodimeric enzyme with a novel fold ('BtrG-like'). Active-site mutagenesis showed that Glu98 acts as a general acid/base in the catalytic mechanism; E98A and E98Q mutations completely inactivate the enzyme without altering the overall fold.","method":"Enzyme activity assay (recombinant protein), X-ray crystallography (1.7 Å), site-directed mutagenesis (E98A, E98Q)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — reconstitution in vitro, crystal structure, and mutagenesis in a single study","pmids":["18515354"],"is_preprint":false},{"year":2019,"finding":"GGCT was identified as a downstream effector of oncogenic Ras. GGCT is required for oncogenic Ras-induced primary mouse cell proliferation and transformation, and for in vivo lung cancer formation in the LSL-KrasG12D mouse model. GGCT deficiency is compatible with normal mouse development. GGCT regulates a glutathione (GSH)-reactive oxygen species (ROS) metabolic pathway that alleviates oncogenic stress.","method":"LSL-KrasG12D mouse model (genetic), siRNA knockdown, cell proliferation/transformation assays, in vivo lung cancer model","journal":"iScience","confidence":"High","confidence_rationale":"Tier 2 — clean genetic KO/KD with defined cellular and in vivo phenotypes, multiple orthogonal methods","pmids":["31400748"],"is_preprint":false},{"year":2021,"finding":"Ggct deletion in mice leads to splenomegaly and progressive anaemia due to elevated oxidative damage and shortened red blood cell (RBC) lifespan. Ggct-/- RBCs show increased ROS and are more sensitive to H2O2-induced damage. GSH and its precursor L-cysteine are decreased in Ggct-/- RBCs, establishing a critical role for Ggct in RBC redox balance and lifespan maintenance through regulation of GSH metabolism.","method":"Ggct knockout mouse model, RBC lifespan assay, ROS measurement, GSH/cysteine quantification, H2O2 sensitivity assay","journal":"British journal of haematology","confidence":"High","confidence_rationale":"Tier 2 — clean KO mouse model with multiple orthogonal biochemical and cellular readouts","pmids":["34409610"],"is_preprint":false},{"year":2007,"finding":"C7orf24 (GGCT) protein expression promotes cancer cell proliferation. Knockdown by siRNA significantly inhibited proliferation of bladder cancer cell lines, and stable overexpression in NIH3T3 cells increased growth rate, establishing a role for GGCT in cell proliferation.","method":"siRNA knockdown (MTT assay), stable retroviral overexpression (growth rate assay)","journal":"Proteomics. Clinical applications","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, gain- and loss-of-function with proliferation readout but no pathway mechanism","pmids":["21136669"],"is_preprint":false},{"year":2011,"finding":"NF-Y transcription factor binds to three proximal CCAAT boxes in the TATA-less C7orf24 (GGCT) promoter to drive basal transcription. NF-YB depletion significantly reduces C7orf24 mRNA and protein. C7orf24 expression oscillates during the cell cycle, consistent with NF-Y-mediated cell-cycle-coupled transcription.","method":"Luciferase reporter assay (5'-deleted and site-directed mutant constructs), EMSA, ChIP assay, siRNA knockdown of NF-YB","journal":"The FEBS journal","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (reporter, EMSA, ChIP, KD) in a single study","pmids":["21883928"],"is_preprint":false},{"year":2011,"finding":"GGCT (C7orf24) knockdown by siRNA in osteosarcoma cell lines inhibited cell growth, enhanced cell clustering, inhibited cell motility and invasion. Gene ontology analysis of expression changes implicated cell adhesion and protein transport pathways downstream of GGCT.","method":"siRNA knockdown, proliferation assay, motility/invasion assay, genome-wide gene expression profiling","journal":"Anticancer research","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, loss-of-function with defined cellular phenotypes","pmids":["21508379"],"is_preprint":false},{"year":2016,"finding":"GGCT knockdown in gastric cancer cells (MGC80-3 and AGS) inhibited cell proliferation, reduced colony formation, caused G2/M cell cycle arrest, and induced apoptosis, establishing a role for GGCT in gastric cancer cell cycle progression and survival.","method":"Lentiviral shRNA knockdown, MTT assay, colony formation assay, flow cytometry (cell cycle and apoptosis analysis)","journal":"BMC biochemistry","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, multiple cellular readouts but no direct pathway mechanism identified","pmids":["27905872"],"is_preprint":false},{"year":2020,"finding":"GGCT promotes colorectal cancer cell migration and invasion through regulation of epithelial-mesenchymal transition (EMT), modulating EMT-associated genes including N-cadherin, Vimentin, Snail1, and Snail2.","method":"GGCT knockdown, migration/invasion assays, EMT marker expression (Western blot, qRT-PCR)","journal":"Oncology letters","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, loss-of-function with defined EMT pathway readouts","pmids":["32724344"],"is_preprint":false},{"year":2022,"finding":"GGCT interacts with and stabilizes CD44 protein in papillary thyroid cancer (PTC) cells. miR-205-5p binds the 3'-UTR of GGCT mRNA (confirmed by dual-luciferase reporter and RNA pulldown) to suppress GGCT, thereby downregulating CD44. GGCT knockdown inhibited growth and metastasis in vitro and in vivo and reduced mesenchymal markers.","method":"Co-immunoprecipitation, dual-luciferase reporter assay, RNA-RNA pulldown, siRNA knockdown, xenograft mouse model","journal":"Endocrinology","confidence":"Medium","confidence_rationale":"Tier 2/3 — Co-IP and reporter assay establish interaction, single lab","pmids":["35213720"],"is_preprint":false},{"year":2022,"finding":"GGCT physically interacts with MRPL9 (mitochondrial ribosomal protein L9) in papillary thyroid cancer cells, as shown by immunofluorescence co-localization and co-immunoprecipitation. Knockdown of either GGCT or MRPL9 inhibits the MAPK/ERK signaling pathway, suppresses cell proliferation and migration in vitro, and inhibits xenograft tumor growth and lung metastasis in vivo.","method":"Immunofluorescence, co-immunoprecipitation, shRNA knockdown, MAPK/ERK pathway analysis, xenograft mouse model","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2/3 — reciprocal co-localization and Co-IP establish interaction; pathway placement by downstream readout; single lab","pmids":["36233293"],"is_preprint":false},{"year":2024,"finding":"GGCT promotes the protein stability of RPS15A in papillary thyroid cancer cells, as shown by co-immunoprecipitation followed by LC-MS/MS. RPS15A stabilization by GGCT suppresses p53 expression, which in turn maintains SLC7A11 expression, thereby sustaining GSH synthesis and inhibiting ferroptosis. GGCT knockdown promotes ferroptosis (increased MDA and ROS, decreased GSH). miR-205-5p targets the 3'-UTR of GGCT to suppress this pathway.","method":"Co-immunoprecipitation + LC-MS/MS, Western blot (p53, SLC7A11, RPS15A), ROS/MDA/GSH measurement, xenograft assay, miRNA 3'-UTR reporter","journal":"Cancer science","confidence":"Medium","confidence_rationale":"Tier 2 — MS-confirmed interaction, pathway placement via RPS15A/p53/SLC7A11 axis with multiple orthogonal readouts; single lab","pmids":["40044122"],"is_preprint":false},{"year":2025,"finding":"GGCT-derived pyroglutamic acid (its enzymatic byproduct) can bind aggregating proteins and drive protein aggregation. Genetic and pharmacological inhibition of GGCT prevents protein aggregation in drug-resistant glioblastoma cells and reduces oxidative stress. GGCT expression is elevated upon drug resistance and is associated with increased mitochondrial function.","method":"Genetic GGCT knockdown, pharmacological GGCT inhibition (Pro-GA), protein aggregation assays, oxidative stress measurement, patient tumor immunostaining","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2/3 — mechanistic link between enzymatic product and protein aggregation established by genetic and pharmacological inhibition; single lab","pmids":["39949960"],"is_preprint":false},{"year":2024,"finding":"Myc directly upregulates Ggct transcription by binding to the Ggct promoter. Deletion of the Myc binding site in the Ggct promoter by genome editing attenuates the tumorigenic potential of p53-deficient osteosarcoma cells. Ggct deletion suppresses p53-deficient osteosarcomagenesis in mice.","method":"ChIP (Myc binding to Ggct promoter), genome editing (CRISPR deletion of Myc binding site), Ggct conditional knockout mouse model, tumorigenesis assay","journal":"Cancer science","confidence":"High","confidence_rationale":"Tier 1/2 — direct promoter binding confirmed by ChIP, genome editing of binding site, and in vivo KO phenotype; multiple orthogonal methods","pmids":["38924236"],"is_preprint":false},{"year":2016,"finding":"Eighteen N-acyl-L-alanine analogues were tested as GGCT inhibitors using recombinant human GGCT protein. N-glutaryl-L-alanine was identified as the most potent inhibitor, providing insight into the active-site substrate requirements of human GGCT.","method":"In vitro enzyme inhibition assay with recombinant human GGCT protein","journal":"Chemical & pharmaceutical bulletin","confidence":"Medium","confidence_rationale":"Tier 1 — direct in vitro enzyme assay; single lab, single method","pmids":["27373633"],"is_preprint":false},{"year":2009,"finding":"C7orf24 (GGCT) mRNA is expressed in multiple rat tissues, with highest levels in liver (hepatocytes) and kidney (renal tubules), as determined by quantitative RT-PCR and in situ hybridization histochemistry, suggesting important metabolic roles in these organs.","method":"RT-PCR, quantitative RT-PCR, in situ hybridization histochemistry","journal":"The journal of histochemistry and cytochemistry","confidence":"Low","confidence_rationale":"Tier 3 — localization without functional consequence established","pmids":["19687470"],"is_preprint":false},{"year":2024,"finding":"In glioma cells, GGCT downregulates REST expression, and REST in turn suppresses miR-34a-5p, which targets the 3'-UTR of GGCT to inhibit GGCT expression, forming a positive feedback loop (GGCT/REST/miR-34a-5p). REST overexpression rescued the inhibitory effects of GGCT knockdown on proliferation, invasion, and xenograft tumor formation.","method":"RNA-seq, RT-qPCR, Western blot, dual luciferase reporter assay, in vitro and in vivo rescue experiments (REST overexpression)","journal":"Translational oncology","confidence":"Medium","confidence_rationale":"Tier 2/3 — pathway placement via epistasis and reporter assay; single lab with multiple readouts","pmids":["39128259"],"is_preprint":false}],"current_model":"GGCT (C7orf24) is a homodimeric gamma-glutamyl cyclotransferase that converts gamma-glutamyl dipeptides to 5-oxoproline and free amino acids via a Glu98-dependent acid/base mechanism, thereby regulating glutathione (GSH) homeostasis; it is transcriptionally activated by NF-Y (via CCAAT box elements) and by Myc (direct promoter binding), functions as a downstream effector of oncogenic Ras to alleviate ROS-mediated oncogenic stress, is essential for red blood cell antioxidant defense and lifespan in mice, promotes cancer cell proliferation/invasion through EMT and MAPK/ERK pathways (partly via interaction with MRPL9 and stabilization of RPS15A/p53/SLC7A11), and its enzymatic product pyroglutamic acid can drive protein aggregation in drug-resistant glioblastoma."},"narrative":{"teleology":[{"year":2007,"claim":"Before any mechanistic characterization, GGCT (C7orf24) was shown to promote cancer cell proliferation—establishing it as a functionally relevant gene in tumor biology but without any known enzymatic activity or pathway placement.","evidence":"siRNA knockdown in bladder cancer cells and stable overexpression in NIH3T3 with proliferation readouts","pmids":["21136669"],"confidence":"Medium","gaps":["No enzymatic activity known","Mechanism of proliferative effect unknown","No in vivo validation"]},{"year":2008,"claim":"The molecular identity of GGCT was established: it is a gamma-glutamyl cyclotransferase with a novel homodimeric fold, and Glu98 was identified as the catalytic residue essential for its acid/base mechanism—providing the first biochemical framework for this protein.","evidence":"Recombinant enzyme assay, X-ray crystallography at 1.7 Å, and E98A/E98Q site-directed mutagenesis","pmids":["18515354"],"confidence":"High","gaps":["Physiological substrates in vivo not defined","No connection to GSH metabolism yet established","No structural basis for inhibitor design"]},{"year":2011,"claim":"Transcriptional regulation of GGCT was elucidated: NF-Y drives basal transcription through CCAAT boxes in the TATA-less promoter, and GGCT expression oscillates during the cell cycle, linking its expression to proliferative programs.","evidence":"Luciferase reporters with deletion/mutation constructs, EMSA, ChIP for NF-Y, siRNA knockdown of NF-YB","pmids":["21883928"],"confidence":"High","gaps":["Whether cell-cycle oscillation is functionally required unknown","Other transcription factors not yet identified","Post-translational regulation unexplored"]},{"year":2016,"claim":"GGCT's pro-proliferative role was extended to gastric cancer, where knockdown caused G2/M arrest and apoptosis, and N-glutaryl-L-alanine was identified as a potent active-site inhibitor, providing a pharmacological tool.","evidence":"shRNA knockdown with cell cycle/apoptosis flow cytometry; in vitro enzyme inhibition assay with recombinant GGCT","pmids":["27905872","27373633"],"confidence":"Medium","gaps":["Whether enzymatic activity is required for proliferative effects unknown","No in vivo inhibitor testing","Mechanism connecting enzymatic product to cell cycle not defined"]},{"year":2019,"claim":"GGCT was placed as a downstream effector of oncogenic Ras, required for Ras-driven transformation and lung tumorigenesis in vivo, while being dispensable for normal development—establishing a specific oncogenic context for GGCT function through GSH-ROS regulation.","evidence":"LSL-KrasG12D mouse model, Ggct knockout mice, siRNA, proliferation/transformation assays, ROS/GSH measurements","pmids":["31400748"],"confidence":"High","gaps":["How Ras signaling upregulates GGCT not defined","Whether GGCT is required for other oncogene-driven cancers unknown","Tissue-specific requirements not mapped"]},{"year":2020,"claim":"GGCT was connected to the EMT program: knockdown in colorectal cancer cells reduced N-cadherin, Vimentin, and Snail expression and suppressed migration/invasion, identifying a downstream pathway by which GGCT promotes metastatic behavior.","evidence":"GGCT knockdown with Western blot and qRT-PCR for EMT markers, Transwell migration/invasion assays","pmids":["32724344"],"confidence":"Medium","gaps":["Whether EMT regulation is direct or secondary to metabolic changes unknown","No in vivo metastasis model","Upstream signals connecting GGCT to EMT transcription factors not identified"]},{"year":2021,"claim":"A physiological role for GGCT was established in vivo: Ggct-null mice develop splenomegaly and progressive anemia due to elevated ROS, decreased GSH and cysteine in RBCs, and shortened erythrocyte lifespan—demonstrating that GGCT is essential for red cell redox homeostasis.","evidence":"Ggct knockout mouse, RBC lifespan assay, ROS measurement, GSH/cysteine quantification, H2O2 sensitivity assay","pmids":["34409610"],"confidence":"High","gaps":["Mechanism by which GGCT maintains cysteine supply not fully resolved","Whether other hematopoietic lineages are affected unknown","Compensatory pathways (e.g., 5-oxoprolinase) not characterized"]},{"year":2022,"claim":"Direct protein-protein interactions of GGCT were identified in thyroid cancer: GGCT binds and stabilizes CD44 and separately interacts with MRPL9 to activate MAPK/ERK signaling, connecting GGCT to non-enzymatic signaling functions.","evidence":"Co-immunoprecipitation, immunofluorescence co-localization, shRNA knockdown with MAPK/ERK readout, xenograft models","pmids":["35213720","36233293"],"confidence":"Medium","gaps":["Whether GGCT enzymatic activity is needed for these protein interactions unknown","Reciprocal validation of CD44 interaction limited","How MRPL9 interaction activates ERK mechanistically unclear"]},{"year":2024,"claim":"Three advances converged: Myc was identified as a direct transcriptional activator of GGCT (promoter binding confirmed by ChIP); GGCT was shown to stabilize RPS15A, suppressing p53 and maintaining SLC7A11-dependent GSH synthesis to inhibit ferroptosis; and a GGCT/REST/miR-34a-5p positive feedback loop was discovered in glioma—placing GGCT at the intersection of oncogenic transcription, ferroptosis resistance, and feedback-controlled self-amplification.","evidence":"ChIP and CRISPR deletion of Myc binding site with tumorigenesis assay; Co-IP + LC-MS/MS for RPS15A with p53/SLC7A11/ferroptosis readouts; RNA-seq and dual-luciferase reporter for REST/miR-34a-5p loop with rescue experiments","pmids":["38924236","40044122","39128259"],"confidence":"Medium","gaps":["Whether Myc-driven GGCT transcription is context-dependent beyond osteosarcoma unknown","RPS15A stabilization mechanism (direct binding vs. indirect) not fully resolved","REST feedback loop not validated outside glioma"]},{"year":2025,"claim":"A novel non-canonical function was uncovered: GGCT-derived pyroglutamic acid directly binds aggregating proteins and drives protein aggregation in drug-resistant glioblastoma, linking GGCT catalytic output to proteostatic collapse rather than solely to GSH metabolism.","evidence":"Genetic and pharmacological GGCT inhibition (Pro-GA), protein aggregation assays, oxidative stress measurement, patient tumor immunostaining","pmids":["39949960"],"confidence":"Medium","gaps":["Structural basis for pyroglutamic acid–protein interaction not determined","Whether this aggregation mechanism operates in non-glioblastoma contexts unknown","Single lab finding not yet independently confirmed"]},{"year":null,"claim":"Key unresolved questions include whether GGCT's enzymatic activity versus its protein-protein interactions are independently required for its oncogenic functions, the structural basis of its non-enzymatic partner interactions, and how GGCT coordinates GSH homeostasis with ferroptosis resistance across different tissue contexts.","evidence":"","pmids":[],"confidence":"High","gaps":["Separation-of-function mutants (enzymatic vs. scaffolding) have not been generated","No structural model for GGCT-MRPL9 or GGCT-RPS15A complexes","In vivo relevance of pyroglutamic acid-driven aggregation beyond glioblastoma untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,13]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[8,10]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,9]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[6,10]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[9,15]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[4,6]}],"complexes":[],"partners":["MRPL9","RPS15A","CD44","NFYB"],"other_free_text":[]},"mechanistic_narrative":"GGCT is a homodimeric gamma-glutamyl cyclotransferase that catalyzes the conversion of gamma-glutamyl dipeptides to 5-oxoproline (pyroglutamic acid) and free amino acids via a Glu98-dependent acid/base mechanism, thereby participating in glutathione homeostasis and cellular redox regulation [PMID:18515354, PMID:34409610]. In mice, GGCT is dispensable for normal development but essential for red blood cell antioxidant defense and lifespan, as Ggct deletion causes progressive anemia with elevated ROS and depleted GSH/cysteine in erythrocytes [PMID:34409610]; GGCT also functions as a critical downstream effector of oncogenic Ras, sustaining transformed cell proliferation by buffering ROS through the GSH pathway [PMID:31400748]. Transcriptionally activated by NF-Y (via CCAAT box elements) and directly by Myc (promoter binding), GGCT promotes cancer cell proliferation, EMT-driven invasion, and ferroptosis resistance through interactions with MRPL9 and stabilization of RPS15A, which suppresses p53 and maintains SLC7A11-dependent GSH synthesis [PMID:21883928, PMID:38924236, PMID:36233293, PMID:40044122]. Its enzymatic product pyroglutamic acid can additionally drive protein aggregation in drug-resistant glioblastoma, linking GGCT catalytic output to proteostatic stress [PMID:39949960]."},"prefetch_data":{"uniprot":{"accession":"O75223","full_name":"Gamma-glutamylcyclotransferase","aliases":["Cytochrome c-releasing factor 21"],"length_aa":188,"mass_kda":21.0,"function":"Catalyzes the formation of 5-oxoproline from gamma-glutamyl dipeptides and may play a significant role in glutathione homeostasis (PubMed:18515354). Induces release of cytochrome c from mitochondria with resultant induction of apoptosis (PubMed:16765912)","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/O75223/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GGCT","classification":"Not Classified","n_dependent_lines":3,"n_total_lines":1208,"dependency_fraction":0.0024834437086092716},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"KRAS","stoichiometry":0.2},{"gene":"RBBP4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/GGCT","total_profiled":1310},"omim":[{"mim_id":"614587","title":"CHAC GLUTATHIONE-SPECIFIC GAMMA-GLUTAMYLCYCLOTRANSFERASE 1; CHAC1","url":"https://www.omim.org/entry/614587"},{"mim_id":"613378","title":"AIG2-LIKE DOMAIN-CONTAINING PROTEIN 1; A2LD1","url":"https://www.omim.org/entry/613378"},{"mim_id":"260005","title":"5-@OXOPROLINASE DEFICIENCY; OPLAHD","url":"https://www.omim.org/entry/260005"},{"mim_id":"137170","title":"GAMMA-GLUTAMYL CYCLOTRANSFERASE; GGCT","url":"https://www.omim.org/entry/137170"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/GGCT"},"hgnc":{"alias_symbol":["MGC3077","CRF21","Ggc"],"prev_symbol":["C7orf24","GCTG"]},"alphafold":{"accession":"O75223","domains":[{"cath_id":"3.10.490.10","chopping":"17-177","consensus_level":"high","plddt":97.444,"start":17,"end":177}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O75223","model_url":"https://alphafold.ebi.ac.uk/files/AF-O75223-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O75223-F1-predicted_aligned_error_v6.png","plddt_mean":93.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GGCT","jax_strain_url":"https://www.jax.org/strain/search?query=GGCT"},"sequence":{"accession":"O75223","fasta_url":"https://rest.uniprot.org/uniprotkb/O75223.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O75223/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O75223"}},"corpus_meta":[{"pmid":"31332381","id":"PMC_31332381","title":"Long-read sequencing identifies GGC repeat expansions in NOTCH2NLC associated with neuronal intranuclear inclusion disease.","date":"2019","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/31332381","citation_count":394,"is_preprint":false},{"pmid":"7728763","id":"PMC_7728763","title":"The CAG and GGC microsatellites of the androgen receptor gene are in linkage disequilibrium in men with prostate cancer.","date":"1995","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/7728763","citation_count":369,"is_preprint":false},{"pmid":"31819945","id":"PMC_31819945","title":"Expansion of GGC repeat in the human-specific NOTCH2NLC gene is associated with essential tremor.","date":"2020","source":"Brain : a journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/31819945","citation_count":162,"is_preprint":false},{"pmid":"20080938","id":"PMC_20080938","title":"Variant CCG and GGC repeats within the CTG expansion dramatically modify mutational dynamics and likely contribute toward unusual symptoms in some myotonic dystrophy type 1 patients.","date":"2010","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/20080938","citation_count":132,"is_preprint":false},{"pmid":"33887199","id":"PMC_33887199","title":"Translation of GGC repeat expansions into a toxic polyglycine protein in NIID defines a novel class of human genetic disorders: The polyG diseases.","date":"2021","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/33887199","citation_count":123,"is_preprint":false},{"pmid":"32413282","id":"PMC_32413282","title":"Expansion of GGC Repeat in GIPC1 Is Associated with Oculopharyngodistal Myopathy.","date":"2020","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32413282","citation_count":116,"is_preprint":false},{"pmid":"18515354","id":"PMC_18515354","title":"The identification and structural characterization of C7orf24 as gamma-glutamyl cyclotransferase. 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Crystal structure at 1.7 Å resolution revealed a homodimeric enzyme with a novel fold ('BtrG-like'). Active-site mutagenesis showed that Glu98 acts as a general acid/base in the catalytic mechanism; E98A and E98Q mutations completely inactivate the enzyme without altering the overall fold.\",\n      \"method\": \"Enzyme activity assay (recombinant protein), X-ray crystallography (1.7 Å), site-directed mutagenesis (E98A, E98Q)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution in vitro, crystal structure, and mutagenesis in a single study\",\n      \"pmids\": [\"18515354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GGCT was identified as a downstream effector of oncogenic Ras. GGCT is required for oncogenic Ras-induced primary mouse cell proliferation and transformation, and for in vivo lung cancer formation in the LSL-KrasG12D mouse model. GGCT deficiency is compatible with normal mouse development. GGCT regulates a glutathione (GSH)-reactive oxygen species (ROS) metabolic pathway that alleviates oncogenic stress.\",\n      \"method\": \"LSL-KrasG12D mouse model (genetic), siRNA knockdown, cell proliferation/transformation assays, in vivo lung cancer model\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean genetic KO/KD with defined cellular and in vivo phenotypes, multiple orthogonal methods\",\n      \"pmids\": [\"31400748\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Ggct deletion in mice leads to splenomegaly and progressive anaemia due to elevated oxidative damage and shortened red blood cell (RBC) lifespan. Ggct-/- RBCs show increased ROS and are more sensitive to H2O2-induced damage. GSH and its precursor L-cysteine are decreased in Ggct-/- RBCs, establishing a critical role for Ggct in RBC redox balance and lifespan maintenance through regulation of GSH metabolism.\",\n      \"method\": \"Ggct knockout mouse model, RBC lifespan assay, ROS measurement, GSH/cysteine quantification, H2O2 sensitivity assay\",\n      \"journal\": \"British journal of haematology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO mouse model with multiple orthogonal biochemical and cellular readouts\",\n      \"pmids\": [\"34409610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"C7orf24 (GGCT) protein expression promotes cancer cell proliferation. Knockdown by siRNA significantly inhibited proliferation of bladder cancer cell lines, and stable overexpression in NIH3T3 cells increased growth rate, establishing a role for GGCT in cell proliferation.\",\n      \"method\": \"siRNA knockdown (MTT assay), stable retroviral overexpression (growth rate assay)\",\n      \"journal\": \"Proteomics. Clinical applications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, gain- and loss-of-function with proliferation readout but no pathway mechanism\",\n      \"pmids\": [\"21136669\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"NF-Y transcription factor binds to three proximal CCAAT boxes in the TATA-less C7orf24 (GGCT) promoter to drive basal transcription. NF-YB depletion significantly reduces C7orf24 mRNA and protein. C7orf24 expression oscillates during the cell cycle, consistent with NF-Y-mediated cell-cycle-coupled transcription.\",\n      \"method\": \"Luciferase reporter assay (5'-deleted and site-directed mutant constructs), EMSA, ChIP assay, siRNA knockdown of NF-YB\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (reporter, EMSA, ChIP, KD) in a single study\",\n      \"pmids\": [\"21883928\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"GGCT (C7orf24) knockdown by siRNA in osteosarcoma cell lines inhibited cell growth, enhanced cell clustering, inhibited cell motility and invasion. Gene ontology analysis of expression changes implicated cell adhesion and protein transport pathways downstream of GGCT.\",\n      \"method\": \"siRNA knockdown, proliferation assay, motility/invasion assay, genome-wide gene expression profiling\",\n      \"journal\": \"Anticancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, loss-of-function with defined cellular phenotypes\",\n      \"pmids\": [\"21508379\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GGCT knockdown in gastric cancer cells (MGC80-3 and AGS) inhibited cell proliferation, reduced colony formation, caused G2/M cell cycle arrest, and induced apoptosis, establishing a role for GGCT in gastric cancer cell cycle progression and survival.\",\n      \"method\": \"Lentiviral shRNA knockdown, MTT assay, colony formation assay, flow cytometry (cell cycle and apoptosis analysis)\",\n      \"journal\": \"BMC biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, multiple cellular readouts but no direct pathway mechanism identified\",\n      \"pmids\": [\"27905872\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GGCT promotes colorectal cancer cell migration and invasion through regulation of epithelial-mesenchymal transition (EMT), modulating EMT-associated genes including N-cadherin, Vimentin, Snail1, and Snail2.\",\n      \"method\": \"GGCT knockdown, migration/invasion assays, EMT marker expression (Western blot, qRT-PCR)\",\n      \"journal\": \"Oncology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, loss-of-function with defined EMT pathway readouts\",\n      \"pmids\": [\"32724344\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"GGCT interacts with and stabilizes CD44 protein in papillary thyroid cancer (PTC) cells. miR-205-5p binds the 3'-UTR of GGCT mRNA (confirmed by dual-luciferase reporter and RNA pulldown) to suppress GGCT, thereby downregulating CD44. GGCT knockdown inhibited growth and metastasis in vitro and in vivo and reduced mesenchymal markers.\",\n      \"method\": \"Co-immunoprecipitation, dual-luciferase reporter assay, RNA-RNA pulldown, siRNA knockdown, xenograft mouse model\",\n      \"journal\": \"Endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — Co-IP and reporter assay establish interaction, single lab\",\n      \"pmids\": [\"35213720\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"GGCT physically interacts with MRPL9 (mitochondrial ribosomal protein L9) in papillary thyroid cancer cells, as shown by immunofluorescence co-localization and co-immunoprecipitation. Knockdown of either GGCT or MRPL9 inhibits the MAPK/ERK signaling pathway, suppresses cell proliferation and migration in vitro, and inhibits xenograft tumor growth and lung metastasis in vivo.\",\n      \"method\": \"Immunofluorescence, co-immunoprecipitation, shRNA knockdown, MAPK/ERK pathway analysis, xenograft mouse model\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — reciprocal co-localization and Co-IP establish interaction; pathway placement by downstream readout; single lab\",\n      \"pmids\": [\"36233293\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GGCT promotes the protein stability of RPS15A in papillary thyroid cancer cells, as shown by co-immunoprecipitation followed by LC-MS/MS. RPS15A stabilization by GGCT suppresses p53 expression, which in turn maintains SLC7A11 expression, thereby sustaining GSH synthesis and inhibiting ferroptosis. GGCT knockdown promotes ferroptosis (increased MDA and ROS, decreased GSH). miR-205-5p targets the 3'-UTR of GGCT to suppress this pathway.\",\n      \"method\": \"Co-immunoprecipitation + LC-MS/MS, Western blot (p53, SLC7A11, RPS15A), ROS/MDA/GSH measurement, xenograft assay, miRNA 3'-UTR reporter\",\n      \"journal\": \"Cancer science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — MS-confirmed interaction, pathway placement via RPS15A/p53/SLC7A11 axis with multiple orthogonal readouts; single lab\",\n      \"pmids\": [\"40044122\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"GGCT-derived pyroglutamic acid (its enzymatic byproduct) can bind aggregating proteins and drive protein aggregation. Genetic and pharmacological inhibition of GGCT prevents protein aggregation in drug-resistant glioblastoma cells and reduces oxidative stress. GGCT expression is elevated upon drug resistance and is associated with increased mitochondrial function.\",\n      \"method\": \"Genetic GGCT knockdown, pharmacological GGCT inhibition (Pro-GA), protein aggregation assays, oxidative stress measurement, patient tumor immunostaining\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — mechanistic link between enzymatic product and protein aggregation established by genetic and pharmacological inhibition; single lab\",\n      \"pmids\": [\"39949960\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Myc directly upregulates Ggct transcription by binding to the Ggct promoter. Deletion of the Myc binding site in the Ggct promoter by genome editing attenuates the tumorigenic potential of p53-deficient osteosarcoma cells. Ggct deletion suppresses p53-deficient osteosarcomagenesis in mice.\",\n      \"method\": \"ChIP (Myc binding to Ggct promoter), genome editing (CRISPR deletion of Myc binding site), Ggct conditional knockout mouse model, tumorigenesis assay\",\n      \"journal\": \"Cancer science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1/2 — direct promoter binding confirmed by ChIP, genome editing of binding site, and in vivo KO phenotype; multiple orthogonal methods\",\n      \"pmids\": [\"38924236\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Eighteen N-acyl-L-alanine analogues were tested as GGCT inhibitors using recombinant human GGCT protein. N-glutaryl-L-alanine was identified as the most potent inhibitor, providing insight into the active-site substrate requirements of human GGCT.\",\n      \"method\": \"In vitro enzyme inhibition assay with recombinant human GGCT protein\",\n      \"journal\": \"Chemical & pharmaceutical bulletin\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro enzyme assay; single lab, single method\",\n      \"pmids\": [\"27373633\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"C7orf24 (GGCT) mRNA is expressed in multiple rat tissues, with highest levels in liver (hepatocytes) and kidney (renal tubules), as determined by quantitative RT-PCR and in situ hybridization histochemistry, suggesting important metabolic roles in these organs.\",\n      \"method\": \"RT-PCR, quantitative RT-PCR, in situ hybridization histochemistry\",\n      \"journal\": \"The journal of histochemistry and cytochemistry\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — localization without functional consequence established\",\n      \"pmids\": [\"19687470\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In glioma cells, GGCT downregulates REST expression, and REST in turn suppresses miR-34a-5p, which targets the 3'-UTR of GGCT to inhibit GGCT expression, forming a positive feedback loop (GGCT/REST/miR-34a-5p). REST overexpression rescued the inhibitory effects of GGCT knockdown on proliferation, invasion, and xenograft tumor formation.\",\n      \"method\": \"RNA-seq, RT-qPCR, Western blot, dual luciferase reporter assay, in vitro and in vivo rescue experiments (REST overexpression)\",\n      \"journal\": \"Translational oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — pathway placement via epistasis and reporter assay; single lab with multiple readouts\",\n      \"pmids\": [\"39128259\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GGCT (C7orf24) is a homodimeric gamma-glutamyl cyclotransferase that converts gamma-glutamyl dipeptides to 5-oxoproline and free amino acids via a Glu98-dependent acid/base mechanism, thereby regulating glutathione (GSH) homeostasis; it is transcriptionally activated by NF-Y (via CCAAT box elements) and by Myc (direct promoter binding), functions as a downstream effector of oncogenic Ras to alleviate ROS-mediated oncogenic stress, is essential for red blood cell antioxidant defense and lifespan in mice, promotes cancer cell proliferation/invasion through EMT and MAPK/ERK pathways (partly via interaction with MRPL9 and stabilization of RPS15A/p53/SLC7A11), and its enzymatic product pyroglutamic acid can drive protein aggregation in drug-resistant glioblastoma.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"GGCT is a homodimeric gamma-glutamyl cyclotransferase that catalyzes the conversion of gamma-glutamyl dipeptides to 5-oxoproline (pyroglutamic acid) and free amino acids via a Glu98-dependent acid/base mechanism, thereby participating in glutathione homeostasis and cellular redox regulation [PMID:18515354, PMID:34409610]. In mice, GGCT is dispensable for normal development but essential for red blood cell antioxidant defense and lifespan, as Ggct deletion causes progressive anemia with elevated ROS and depleted GSH/cysteine in erythrocytes [PMID:34409610]; GGCT also functions as a critical downstream effector of oncogenic Ras, sustaining transformed cell proliferation by buffering ROS through the GSH pathway [PMID:31400748]. Transcriptionally activated by NF-Y (via CCAAT box elements) and directly by Myc (promoter binding), GGCT promotes cancer cell proliferation, EMT-driven invasion, and ferroptosis resistance through interactions with MRPL9 and stabilization of RPS15A, which suppresses p53 and maintains SLC7A11-dependent GSH synthesis [PMID:21883928, PMID:38924236, PMID:36233293, PMID:40044122]. Its enzymatic product pyroglutamic acid can additionally drive protein aggregation in drug-resistant glioblastoma, linking GGCT catalytic output to proteostatic stress [PMID:39949960].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Before any mechanistic characterization, GGCT (C7orf24) was shown to promote cancer cell proliferation—establishing it as a functionally relevant gene in tumor biology but without any known enzymatic activity or pathway placement.\",\n      \"evidence\": \"siRNA knockdown in bladder cancer cells and stable overexpression in NIH3T3 with proliferation readouts\",\n      \"pmids\": [\"21136669\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No enzymatic activity known\", \"Mechanism of proliferative effect unknown\", \"No in vivo validation\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"The molecular identity of GGCT was established: it is a gamma-glutamyl cyclotransferase with a novel homodimeric fold, and Glu98 was identified as the catalytic residue essential for its acid/base mechanism—providing the first biochemical framework for this protein.\",\n      \"evidence\": \"Recombinant enzyme assay, X-ray crystallography at 1.7 Å, and E98A/E98Q site-directed mutagenesis\",\n      \"pmids\": [\"18515354\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological substrates in vivo not defined\", \"No connection to GSH metabolism yet established\", \"No structural basis for inhibitor design\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Transcriptional regulation of GGCT was elucidated: NF-Y drives basal transcription through CCAAT boxes in the TATA-less promoter, and GGCT expression oscillates during the cell cycle, linking its expression to proliferative programs.\",\n      \"evidence\": \"Luciferase reporters with deletion/mutation constructs, EMSA, ChIP for NF-Y, siRNA knockdown of NF-YB\",\n      \"pmids\": [\"21883928\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether cell-cycle oscillation is functionally required unknown\", \"Other transcription factors not yet identified\", \"Post-translational regulation unexplored\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"GGCT's pro-proliferative role was extended to gastric cancer, where knockdown caused G2/M arrest and apoptosis, and N-glutaryl-L-alanine was identified as a potent active-site inhibitor, providing a pharmacological tool.\",\n      \"evidence\": \"shRNA knockdown with cell cycle/apoptosis flow cytometry; in vitro enzyme inhibition assay with recombinant GGCT\",\n      \"pmids\": [\"27905872\", \"27373633\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether enzymatic activity is required for proliferative effects unknown\", \"No in vivo inhibitor testing\", \"Mechanism connecting enzymatic product to cell cycle not defined\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"GGCT was placed as a downstream effector of oncogenic Ras, required for Ras-driven transformation and lung tumorigenesis in vivo, while being dispensable for normal development—establishing a specific oncogenic context for GGCT function through GSH-ROS regulation.\",\n      \"evidence\": \"LSL-KrasG12D mouse model, Ggct knockout mice, siRNA, proliferation/transformation assays, ROS/GSH measurements\",\n      \"pmids\": [\"31400748\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How Ras signaling upregulates GGCT not defined\", \"Whether GGCT is required for other oncogene-driven cancers unknown\", \"Tissue-specific requirements not mapped\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"GGCT was connected to the EMT program: knockdown in colorectal cancer cells reduced N-cadherin, Vimentin, and Snail expression and suppressed migration/invasion, identifying a downstream pathway by which GGCT promotes metastatic behavior.\",\n      \"evidence\": \"GGCT knockdown with Western blot and qRT-PCR for EMT markers, Transwell migration/invasion assays\",\n      \"pmids\": [\"32724344\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether EMT regulation is direct or secondary to metabolic changes unknown\", \"No in vivo metastasis model\", \"Upstream signals connecting GGCT to EMT transcription factors not identified\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"A physiological role for GGCT was established in vivo: Ggct-null mice develop splenomegaly and progressive anemia due to elevated ROS, decreased GSH and cysteine in RBCs, and shortened erythrocyte lifespan—demonstrating that GGCT is essential for red cell redox homeostasis.\",\n      \"evidence\": \"Ggct knockout mouse, RBC lifespan assay, ROS measurement, GSH/cysteine quantification, H2O2 sensitivity assay\",\n      \"pmids\": [\"34409610\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which GGCT maintains cysteine supply not fully resolved\", \"Whether other hematopoietic lineages are affected unknown\", \"Compensatory pathways (e.g., 5-oxoprolinase) not characterized\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Direct protein-protein interactions of GGCT were identified in thyroid cancer: GGCT binds and stabilizes CD44 and separately interacts with MRPL9 to activate MAPK/ERK signaling, connecting GGCT to non-enzymatic signaling functions.\",\n      \"evidence\": \"Co-immunoprecipitation, immunofluorescence co-localization, shRNA knockdown with MAPK/ERK readout, xenograft models\",\n      \"pmids\": [\"35213720\", \"36233293\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether GGCT enzymatic activity is needed for these protein interactions unknown\", \"Reciprocal validation of CD44 interaction limited\", \"How MRPL9 interaction activates ERK mechanistically unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Three advances converged: Myc was identified as a direct transcriptional activator of GGCT (promoter binding confirmed by ChIP); GGCT was shown to stabilize RPS15A, suppressing p53 and maintaining SLC7A11-dependent GSH synthesis to inhibit ferroptosis; and a GGCT/REST/miR-34a-5p positive feedback loop was discovered in glioma—placing GGCT at the intersection of oncogenic transcription, ferroptosis resistance, and feedback-controlled self-amplification.\",\n      \"evidence\": \"ChIP and CRISPR deletion of Myc binding site with tumorigenesis assay; Co-IP + LC-MS/MS for RPS15A with p53/SLC7A11/ferroptosis readouts; RNA-seq and dual-luciferase reporter for REST/miR-34a-5p loop with rescue experiments\",\n      \"pmids\": [\"38924236\", \"40044122\", \"39128259\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether Myc-driven GGCT transcription is context-dependent beyond osteosarcoma unknown\", \"RPS15A stabilization mechanism (direct binding vs. indirect) not fully resolved\", \"REST feedback loop not validated outside glioma\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"A novel non-canonical function was uncovered: GGCT-derived pyroglutamic acid directly binds aggregating proteins and drives protein aggregation in drug-resistant glioblastoma, linking GGCT catalytic output to proteostatic collapse rather than solely to GSH metabolism.\",\n      \"evidence\": \"Genetic and pharmacological GGCT inhibition (Pro-GA), protein aggregation assays, oxidative stress measurement, patient tumor immunostaining\",\n      \"pmids\": [\"39949960\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis for pyroglutamic acid–protein interaction not determined\", \"Whether this aggregation mechanism operates in non-glioblastoma contexts unknown\", \"Single lab finding not yet independently confirmed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include whether GGCT's enzymatic activity versus its protein-protein interactions are independently required for its oncogenic functions, the structural basis of its non-enzymatic partner interactions, and how GGCT coordinates GSH homeostasis with ferroptosis resistance across different tissue contexts.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Separation-of-function mutants (enzymatic vs. scaffolding) have not been generated\", \"No structural model for GGCT-MRPL9 or GGCT-RPS15A complexes\", \"In vivo relevance of pyroglutamic acid-driven aggregation beyond glioblastoma untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 13]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [8, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [6, 10]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [9, 15]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [4, 6]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"MRPL9\",\n      \"RPS15A\",\n      \"CD44\",\n      \"NFYB\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}