{"gene":"AGBL2","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":2011,"finding":"AGBL2 (ATP/GTP binding protein-like 2) is a cytoplasmic carboxypeptidase that detyrosinates the C-terminal EEY region of α-tubulin; knockdown of AGBL2 causes failure of α-tubulin detyrosination, identifying it as a candidate tubulin tyrosine carboxypeptidase (TCP). RARRES1, a transmembrane carboxypeptidase inhibitor, physically interacts with AGBL2 and acts as its cognate inhibitor, as RARRES1 knockdown increases detyrosinated α-tubulin levels.","method":"siRNA knockdown of AGBL2 with immunofluorescence/western blot readout of detyrosinated α-tubulin; co-immunoprecipitation of RARRES1 with AGBL2","journal":"Cancer research","confidence":"High","confidence_rationale":"Tier 2 — reciprocal functional knockdown with specific tubulin modification readout plus Co-IP binding partner identification, moderate evidence","pmids":["21303978"],"is_preprint":false},{"year":2014,"finding":"CCP2 (AGBL2) and CCP3 are deglutamylases that catalyze posttranslational removal of glutamic acid residues from carboxy-terminal tails of tubulin and other substrates; CCP3 additionally hydrolyzes aspartic acids with similar efficiency (deaspartylation). Both enzymes are highly regulated and confined to ciliated tissues.","method":"In vitro enzymatic assays with tubulin and peptide substrates; mass spectrometry-based product analysis; tissue expression analysis","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1 — direct in vitro enzymatic characterization with substrate specificity determination, replicated across multiple CCP family members in same study","pmids":["25103237"],"is_preprint":false},{"year":2017,"finding":"AGBL2 overexpression in hepatocellular carcinoma cells inhibits apoptosis by enhancing IRGM-regulated autophagy, and upregulates TPX2 expression and Aurora A kinase activity to promote cell proliferation.","method":"Ectopic overexpression and knockdown of AGBL2 in HCC cell lines; apoptosis assays; autophagy flux analysis; Aurora A kinase activity assay; in vivo tumor growth in xenograft models","journal":"Cancer letters","confidence":"Medium","confidence_rationale":"Tier 2 — clean KO/OE with defined cellular phenotypes, single lab with multiple orthogonal readouts","pmids":["29126912"],"is_preprint":false},{"year":2014,"finding":"AGBL2 interacts with latexin (a known carboxypeptidase inhibitor) to form immune complexes, and AGBL2 regulates the tubulin tyrosination cycle in breast cancer stem cells; AGBL2 protein is elevated in CD44+/CD24- cancer stem cells undergoing epithelial-to-mesenchymal transition and is associated with chemotherapy resistance.","method":"Co-immunoprecipitation of AGBL2 and latexin; western blot and IHC in sorted CSC populations; in vivo tumor formation in NOD/SCID mice","journal":"World journal of surgical oncology","confidence":"Low","confidence_rationale":"Tier 3 — single Co-IP with limited mechanistic follow-up, single lab","pmids":["24884516"],"is_preprint":false},{"year":2015,"finding":"AGBL2 interacts with latexin in gastric cancer cells, forming immune complexes detectable by co-immunoprecipitation, and together they regulate the tubulin tyrosination cycle and are associated with proliferation and chemotherapy resistance.","method":"Co-immunoprecipitation; immunohistochemistry in gastric cancer specimens; proliferation assays","journal":"Hepato-gastroenterology","confidence":"Low","confidence_rationale":"Tier 3 — single Co-IP, largely phenotypic/clinical, limited mechanistic resolution","pmids":["25916089"],"is_preprint":false},{"year":2024,"finding":"AGBL2 promotes renal cell carcinoma cell proliferation and migration via α-tubulin detyrosination; this effect is partially inhibited by the tubulin carboxypeptidase inhibitor parthenolide. AGBL2 is predominantly localized in the nucleus in RCC cells and enhances phosphorylation of AKT.","method":"AGBL2 knockdown and overexpression in RCC cell lines; proliferation and migration assays; parthenolide inhibitor treatment; subcellular localization by imaging; RNA sequencing of knockdown cells; AKT phosphorylation by western blot","journal":"Heliyon","confidence":"Medium","confidence_rationale":"Tier 2 — KD/OE with specific mechanistic readouts (detyrosination, AKT phosphorylation, pharmacological inhibition), single lab with multiple methods","pmids":["39315218"],"is_preprint":false}],"current_model":"AGBL2 is a cytosolic carboxypeptidase (cytosolic carboxypeptidase 2/CCP2) that catalyzes posttranslational deglutamylation of tubulin C-terminal tails and detyrosination of α-tubulin's C-terminal EEY sequence, thereby regulating microtubule dynamics; its activity is inhibited by RARRES1 (a transmembrane carboxypeptidase inhibitor) and by latexin, and elevated AGBL2 activity in cancer promotes proliferation, migration, and chemotherapy resistance through enhanced α-tubulin detyrosination, modulation of Aurora A kinase activity, IRGM-regulated autophagy, and AKT phosphorylation."},"narrative":{"teleology":[{"year":2011,"claim":"Identification of AGBL2 as a tubulin carboxypeptidase that detyrosinates α-tubulin's C-terminal EEY sequence resolved a long-sought question about the identity of the enzyme (TCP) responsible for tubulin detyrosination, and simultaneously revealed RARRES1 as its cognate inhibitor.","evidence":"siRNA knockdown of AGBL2 with immunofluorescence/western blot readout of detyrosinated α-tubulin; co-immunoprecipitation of RARRES1 with AGBL2 in human cells","pmids":["21303978"],"confidence":"High","gaps":["Whether AGBL2 is the sole or primary TCP in vivo versus other CCP family members","Structural basis of RARRES1 inhibition of AGBL2 is unknown","No in vitro reconstitution of AGBL2 enzymatic activity in this study"]},{"year":2014,"claim":"Direct biochemical characterization established AGBL2/CCP2 as a deglutamylase that removes C-terminal glutamate residues from tubulin, defining its substrate specificity and distinguishing it from CCP3's dual deglutamylase/deaspartylase activity.","evidence":"In vitro enzymatic assays with tubulin and peptide substrates; mass spectrometry-based product analysis","pmids":["25103237"],"confidence":"High","gaps":["Full range of non-tubulin substrates not established","Kinetic parameters and catalytic mechanism remain unresolved","Tissue restriction to ciliated tissues not mechanistically explained"]},{"year":2014,"claim":"Identification of latexin as a second carboxypeptidase inhibitor physically interacting with AGBL2 expanded the regulatory landscape and linked AGBL2 to cancer stem cell biology and chemotherapy resistance, though mechanistic depth was limited.","evidence":"Co-immunoprecipitation of AGBL2 and latexin in breast cancer stem cells; IHC in sorted CD44+/CD24− populations","pmids":["24884516"],"confidence":"Low","gaps":["Single Co-IP without reciprocal validation or domain mapping","Whether latexin directly inhibits AGBL2 catalytic activity or acts via indirect mechanisms is untested","Functional consequence of AGBL2–latexin interaction on tubulin modification not quantified"]},{"year":2017,"claim":"Demonstrating that AGBL2 overexpression suppresses apoptosis via IRGM-regulated autophagy and activates Aurora A kinase through TPX2 upregulation revealed downstream oncogenic effector pathways beyond tubulin detyrosination.","evidence":"Ectopic overexpression and knockdown in HCC cell lines; apoptosis, autophagy flux, and Aurora A kinase activity assays; xenograft tumor models","pmids":["29126912"],"confidence":"Medium","gaps":["Whether AGBL2 regulates IRGM and TPX2/Aurora A through its carboxypeptidase activity or via a separate function is unclear","Mechanism linking tubulin detyrosination to autophagy induction not established","Single lab study without independent replication"]},{"year":2024,"claim":"Observation that AGBL2 enhances AKT phosphorylation and that its pro-tumorigenic effects are partially blocked by parthenolide broadened the signaling outputs of AGBL2 and provided pharmacological validation of its carboxypeptidase activity in cancer.","evidence":"AGBL2 knockdown/overexpression in RCC cell lines; parthenolide treatment; AKT phosphorylation by western blot; RNA sequencing","pmids":["39315218"],"confidence":"Medium","gaps":["Direct versus indirect regulation of AKT by AGBL2 is unresolved","Parthenolide is not a specific AGBL2 inhibitor, limiting mechanistic interpretation","Nuclear localization of AGBL2 observed in RCC cells lacks functional characterization"]},{"year":null,"claim":"The structural basis of AGBL2 catalysis, its full non-tubulin substrate repertoire, the functional significance of its reported nuclear localization, and the precise mechanism by which AGBL2 carboxypeptidase activity connects to downstream signaling pathways (AKT, Aurora A, autophagy) remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal or cryo-EM structure of AGBL2 available","Systematic identification of non-tubulin substrates not performed","Nuclear function of AGBL2 unexplored"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[5]}],"pathway":[],"complexes":[],"partners":["RARRES1","LXN","TUBA1A"],"other_free_text":[]},"mechanistic_narrative":"AGBL2 (also designated cytosolic carboxypeptidase 2/CCP2) is a metallocarboxypeptidase that catalyzes detyrosination of the C-terminal EEY motif of α-tubulin and deglutamylation of tubulin C-terminal tails, thereby regulating the tubulin tyrosination cycle and microtubule dynamics [PMID:21303978, PMID:25103237]. Its enzymatic activity is inhibited by the transmembrane carboxypeptidase inhibitor RARRES1 and by latexin, which form physical complexes with AGBL2 [PMID:21303978, PMID:24884516]. In cancer cells, AGBL2 overexpression promotes proliferation, migration, and chemotherapy resistance through enhanced α-tubulin detyrosination, upregulation of Aurora A kinase activity via TPX2, stimulation of IRGM-regulated autophagy, and activation of AKT phosphorylation [PMID:29126912, PMID:39315218]."},"prefetch_data":{"uniprot":{"accession":"Q5U5Z8","full_name":"Cytosolic carboxypeptidase 2","aliases":["ATP/GTP-binding protein-like 2","Protein deglutamylase CCP2"],"length_aa":902,"mass_kda":104.2,"function":"Metallocarboxypeptidase that mediates deglutamylation of tubulin and non-tubulin target proteins. Catalyzes the removal of polyglutamate side chains present on the gamma-carboxyl group of glutamate residues within the C-terminal tail of tubulin protein. Specifically cleaves tubulin long-side-chains, while it is not able to remove the branching point glutamate. Also catalyzes the removal of polyglutamate residues from the carboxy-terminus of non-tubulin proteins such as MYLK","subcellular_location":"Cytoplasm, cytosol; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriole; Cytoplasm, cytoskeleton, cilium basal body","url":"https://www.uniprot.org/uniprotkb/Q5U5Z8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/AGBL2","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/AGBL2","total_profiled":1310},"omim":[{"mim_id":"620485","title":"TUBULIN TYROSINE LIGASE-LIKE 13; TTLL13","url":"https://www.omim.org/entry/620485"},{"mim_id":"618845","title":"VERTEBRAL, CARDIAC, RENAL, AND LIMB DEFECTS SYNDROME 3; VCRL3","url":"https://www.omim.org/entry/618845"},{"mim_id":"618738","title":"TUBULIN TYROSINE LIGASE-LIKE 4; TTLL4","url":"https://www.omim.org/entry/618738"},{"mim_id":"617346","title":"ATP/GTP-BINDING PROTEIN-LIKE 3; AGBL3","url":"https://www.omim.org/entry/617346"},{"mim_id":"617345","title":"ATP/GTP-BINDING PROTEIN-LIKE 2; AGBL2","url":"https://www.omim.org/entry/617345"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoli","reliability":"Supported"},{"location":"Basal body","reliability":"Supported"},{"location":"Cytosol","reliability":"Supported"},{"location":"Flagellar centriole","reliability":"Supported"},{"location":"Mid piece","reliability":"Additional"},{"location":"Principal piece","reliability":"Additional"},{"location":"End piece","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"fallopian tube","ntpm":5.1},{"tissue":"testis","ntpm":11.4}],"url":"https://www.proteinatlas.org/search/AGBL2"},"hgnc":{"alias_symbol":["FLJ23598","CCP2"],"prev_symbol":[]},"alphafold":{"accession":"Q5U5Z8","domains":[{"cath_id":"2.60.40.3120","chopping":"181-394","consensus_level":"medium","plddt":91.9024,"start":181,"end":394},{"cath_id":"3.40.630.10","chopping":"399-666","consensus_level":"high","plddt":95.4406,"start":399,"end":666}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5U5Z8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q5U5Z8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q5U5Z8-F1-predicted_aligned_error_v6.png","plddt_mean":71.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=AGBL2","jax_strain_url":"https://www.jax.org/strain/search?query=AGBL2"},"sequence":{"accession":"Q5U5Z8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q5U5Z8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q5U5Z8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q5U5Z8"}},"corpus_meta":[{"pmid":"25103237","id":"PMC_25103237","title":"The cytosolic carboxypeptidases CCP2 and CCP3 catalyze posttranslational removal of acidic amino acids.","date":"2014","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/25103237","citation_count":64,"is_preprint":false},{"pmid":"30700425","id":"PMC_30700425","title":"Porphyromonas gingivalis experimentally induces periodontis and an anti-CCP2-associated arthritis in the rat.","date":"2019","source":"Annals of the rheumatic diseases","url":"https://pubmed.ncbi.nlm.nih.gov/30700425","citation_count":63,"is_preprint":false},{"pmid":"21303978","id":"PMC_21303978","title":"Tumor suppressor RARRES1 interacts with cytoplasmic carboxypeptidase AGBL2 to regulate the α-tubulin tyrosination cycle.","date":"2011","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/21303978","citation_count":57,"is_preprint":false},{"pmid":"15604732","id":"PMC_15604732","title":"The Chlamydomonas reinhardtii proteins Ccp1 and Ccp2 are required for long-term growth, but are not necessary for efficient photosynthesis, in a low-CO2 environment.","date":"2004","source":"Plant molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15604732","citation_count":45,"is_preprint":false},{"pmid":"17286215","id":"PMC_17286215","title":"Autoantibodies to cyclic citrullinated peptide 2 (CCP2) are superior to other potential diagnostic biomarkers for predicting rheumatoid arthritis in early undifferentiated arthritis.","date":"2007","source":"Clinical rheumatology","url":"https://pubmed.ncbi.nlm.nih.gov/17286215","citation_count":37,"is_preprint":false},{"pmid":"29126912","id":"PMC_29126912","title":"AGBL2 promotes cancer cell growth through IRGM-regulated autophagy and enhanced Aurora A activity in hepatocellular carcinoma.","date":"2017","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/29126912","citation_count":34,"is_preprint":false},{"pmid":"22580581","id":"PMC_22580581","title":"Autoantibodies to citrullinated fibrinogen compared with anti-MCV and anti-CCP2 antibodies in diagnosing rheumatoid arthritis at an early stage: data from the French ESPOIR cohort.","date":"2012","source":"Annals of the rheumatic diseases","url":"https://pubmed.ncbi.nlm.nih.gov/22580581","citation_count":33,"is_preprint":false},{"pmid":"23592053","id":"PMC_23592053","title":"Superior performance of the CCP3.1 test compared to CCP2 and MCV in the rheumatoid factor-negative RA population.","date":"2013","source":"Immunologic research","url":"https://pubmed.ncbi.nlm.nih.gov/23592053","citation_count":28,"is_preprint":false},{"pmid":"11090879","id":"PMC_11090879","title":"Positively charged amino acids at the interface between alpha-chain CCP1 and CCP2 of C4BP are required for regulation of the classical C3-convertase.","date":"2000","source":"Molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/11090879","citation_count":25,"is_preprint":false},{"pmid":"15370715","id":"PMC_15370715","title":"Second generation anti-cyclic citrullinated peptide (anti-CCP2) antibodies can replace other anti-filaggrin antibodies and improve rheumatoid arthritis diagnosis.","date":"2004","source":"Scandinavian journal of rheumatology","url":"https://pubmed.ncbi.nlm.nih.gov/15370715","citation_count":20,"is_preprint":false},{"pmid":"29895567","id":"PMC_29895567","title":"Number of individual ACPA reactivities in synovial fluid immune complexes, but not serum anti-CCP2 levels, associate with inflammation and joint destruction in rheumatoid arthritis.","date":"2018","source":"Annals of the rheumatic diseases","url":"https://pubmed.ncbi.nlm.nih.gov/29895567","citation_count":19,"is_preprint":false},{"pmid":"18415774","id":"PMC_18415774","title":"Measurement characteristics of a new rapid anti-CCP2 test compared to the anti-CCP2 ELISA.","date":"2008","source":"Scandinavian journal of rheumatology","url":"https://pubmed.ncbi.nlm.nih.gov/18415774","citation_count":11,"is_preprint":false},{"pmid":"30656490","id":"PMC_30656490","title":"Occurrence of anti-CCP2 and RF isotypes and their relation to age and disease severity among Sudanese patients with rheumatoid arthritis.","date":"2019","source":"Clinical rheumatology","url":"https://pubmed.ncbi.nlm.nih.gov/30656490","citation_count":11,"is_preprint":false},{"pmid":"24884516","id":"PMC_24884516","title":"Clinical implications of AGBL2 expression and its inhibitor latexin in breast cancer.","date":"2014","source":"World journal of surgical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/24884516","citation_count":10,"is_preprint":false},{"pmid":"32307444","id":"PMC_32307444","title":"Expression of RARRES1 and AGBL2 and progression of conventional renal cell carcinoma.","date":"2020","source":"British journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/32307444","citation_count":8,"is_preprint":false},{"pmid":"12492479","id":"PMC_12492479","title":"Role of CCP2 of the C4b-binding protein beta-chain in protein S binding evaluated by mutagenesis and monoclonal antibodies.","date":"2003","source":"European journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12492479","citation_count":8,"is_preprint":false},{"pmid":"31319568","id":"PMC_31319568","title":"Initiated Babesia ovata Sexual Stages under In Vitro Conditions Were Recognized by Anti-CCp2 Antibodies, Showing Changes in the DNA Content by Imaging Flow Cytometry.","date":"2019","source":"Pathogens (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/31319568","citation_count":7,"is_preprint":false},{"pmid":"25916089","id":"PMC_25916089","title":"Effects of AGBL2 on cell proliferation and chemotherapy resistance of gastric cancer.","date":"2015","source":"Hepato-gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/25916089","citation_count":3,"is_preprint":false},{"pmid":"39315218","id":"PMC_39315218","title":"AGBL2 promotes renal cell carcinoma cells proliferation and migration via α-tubulin detyrosination.","date":"2024","source":"Heliyon","url":"https://pubmed.ncbi.nlm.nih.gov/39315218","citation_count":2,"is_preprint":false},{"pmid":"38599655","id":"PMC_38599655","title":"Utility of testing for third-generation anticyclic citrullinated peptide (anti-CCP3) antibodies in individuals who present with new musculoskeletal symptoms but have a negative second-generation anticyclic citrullinated peptide (anti-CCP2) antibody test.","date":"2024","source":"RMD open","url":"https://pubmed.ncbi.nlm.nih.gov/38599655","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11728,"output_tokens":1618,"usd":0.029727},"stage2":{"model":"claude-opus-4-6","input_tokens":4881,"output_tokens":1778,"usd":0.103282},"total_usd":0.133009,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"AGBL2 (ATP/GTP binding protein-like 2) is a cytoplasmic carboxypeptidase that detyrosinates the C-terminal EEY region of α-tubulin; knockdown of AGBL2 causes failure of α-tubulin detyrosination, identifying it as a candidate tubulin tyrosine carboxypeptidase (TCP). RARRES1, a transmembrane carboxypeptidase inhibitor, physically interacts with AGBL2 and acts as its cognate inhibitor, as RARRES1 knockdown increases detyrosinated α-tubulin levels.\",\n      \"method\": \"siRNA knockdown of AGBL2 with immunofluorescence/western blot readout of detyrosinated α-tubulin; co-immunoprecipitation of RARRES1 with AGBL2\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal functional knockdown with specific tubulin modification readout plus Co-IP binding partner identification, moderate evidence\",\n      \"pmids\": [\"21303978\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"CCP2 (AGBL2) and CCP3 are deglutamylases that catalyze posttranslational removal of glutamic acid residues from carboxy-terminal tails of tubulin and other substrates; CCP3 additionally hydrolyzes aspartic acids with similar efficiency (deaspartylation). Both enzymes are highly regulated and confined to ciliated tissues.\",\n      \"method\": \"In vitro enzymatic assays with tubulin and peptide substrates; mass spectrometry-based product analysis; tissue expression analysis\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro enzymatic characterization with substrate specificity determination, replicated across multiple CCP family members in same study\",\n      \"pmids\": [\"25103237\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"AGBL2 overexpression in hepatocellular carcinoma cells inhibits apoptosis by enhancing IRGM-regulated autophagy, and upregulates TPX2 expression and Aurora A kinase activity to promote cell proliferation.\",\n      \"method\": \"Ectopic overexpression and knockdown of AGBL2 in HCC cell lines; apoptosis assays; autophagy flux analysis; Aurora A kinase activity assay; in vivo tumor growth in xenograft models\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KO/OE with defined cellular phenotypes, single lab with multiple orthogonal readouts\",\n      \"pmids\": [\"29126912\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"AGBL2 interacts with latexin (a known carboxypeptidase inhibitor) to form immune complexes, and AGBL2 regulates the tubulin tyrosination cycle in breast cancer stem cells; AGBL2 protein is elevated in CD44+/CD24- cancer stem cells undergoing epithelial-to-mesenchymal transition and is associated with chemotherapy resistance.\",\n      \"method\": \"Co-immunoprecipitation of AGBL2 and latexin; western blot and IHC in sorted CSC populations; in vivo tumor formation in NOD/SCID mice\",\n      \"journal\": \"World journal of surgical oncology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP with limited mechanistic follow-up, single lab\",\n      \"pmids\": [\"24884516\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"AGBL2 interacts with latexin in gastric cancer cells, forming immune complexes detectable by co-immunoprecipitation, and together they regulate the tubulin tyrosination cycle and are associated with proliferation and chemotherapy resistance.\",\n      \"method\": \"Co-immunoprecipitation; immunohistochemistry in gastric cancer specimens; proliferation assays\",\n      \"journal\": \"Hepato-gastroenterology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP, largely phenotypic/clinical, limited mechanistic resolution\",\n      \"pmids\": [\"25916089\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"AGBL2 promotes renal cell carcinoma cell proliferation and migration via α-tubulin detyrosination; this effect is partially inhibited by the tubulin carboxypeptidase inhibitor parthenolide. AGBL2 is predominantly localized in the nucleus in RCC cells and enhances phosphorylation of AKT.\",\n      \"method\": \"AGBL2 knockdown and overexpression in RCC cell lines; proliferation and migration assays; parthenolide inhibitor treatment; subcellular localization by imaging; RNA sequencing of knockdown cells; AKT phosphorylation by western blot\",\n      \"journal\": \"Heliyon\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KD/OE with specific mechanistic readouts (detyrosination, AKT phosphorylation, pharmacological inhibition), single lab with multiple methods\",\n      \"pmids\": [\"39315218\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"AGBL2 is a cytosolic carboxypeptidase (cytosolic carboxypeptidase 2/CCP2) that catalyzes posttranslational deglutamylation of tubulin C-terminal tails and detyrosination of α-tubulin's C-terminal EEY sequence, thereby regulating microtubule dynamics; its activity is inhibited by RARRES1 (a transmembrane carboxypeptidase inhibitor) and by latexin, and elevated AGBL2 activity in cancer promotes proliferation, migration, and chemotherapy resistance through enhanced α-tubulin detyrosination, modulation of Aurora A kinase activity, IRGM-regulated autophagy, and AKT phosphorylation.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"AGBL2 (also designated cytosolic carboxypeptidase 2/CCP2) is a metallocarboxypeptidase that catalyzes detyrosination of the C-terminal EEY motif of α-tubulin and deglutamylation of tubulin C-terminal tails, thereby regulating the tubulin tyrosination cycle and microtubule dynamics [PMID:21303978, PMID:25103237]. Its enzymatic activity is inhibited by the transmembrane carboxypeptidase inhibitor RARRES1 and by latexin, which form physical complexes with AGBL2 [PMID:21303978, PMID:24884516]. In cancer cells, AGBL2 overexpression promotes proliferation, migration, and chemotherapy resistance through enhanced α-tubulin detyrosination, upregulation of Aurora A kinase activity via TPX2, stimulation of IRGM-regulated autophagy, and activation of AKT phosphorylation [PMID:29126912, PMID:39315218].\",\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Identification of AGBL2 as a tubulin carboxypeptidase that detyrosinates α-tubulin's C-terminal EEY sequence resolved a long-sought question about the identity of the enzyme (TCP) responsible for tubulin detyrosination, and simultaneously revealed RARRES1 as its cognate inhibitor.\",\n      \"evidence\": \"siRNA knockdown of AGBL2 with immunofluorescence/western blot readout of detyrosinated α-tubulin; co-immunoprecipitation of RARRES1 with AGBL2 in human cells\",\n      \"pmids\": [\"21303978\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether AGBL2 is the sole or primary TCP in vivo versus other CCP family members\",\n        \"Structural basis of RARRES1 inhibition of AGBL2 is unknown\",\n        \"No in vitro reconstitution of AGBL2 enzymatic activity in this study\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Direct biochemical characterization established AGBL2/CCP2 as a deglutamylase that removes C-terminal glutamate residues from tubulin, defining its substrate specificity and distinguishing it from CCP3's dual deglutamylase/deaspartylase activity.\",\n      \"evidence\": \"In vitro enzymatic assays with tubulin and peptide substrates; mass spectrometry-based product analysis\",\n      \"pmids\": [\"25103237\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Full range of non-tubulin substrates not established\",\n        \"Kinetic parameters and catalytic mechanism remain unresolved\",\n        \"Tissue restriction to ciliated tissues not mechanistically explained\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identification of latexin as a second carboxypeptidase inhibitor physically interacting with AGBL2 expanded the regulatory landscape and linked AGBL2 to cancer stem cell biology and chemotherapy resistance, though mechanistic depth was limited.\",\n      \"evidence\": \"Co-immunoprecipitation of AGBL2 and latexin in breast cancer stem cells; IHC in sorted CD44+/CD24− populations\",\n      \"pmids\": [\"24884516\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Single Co-IP without reciprocal validation or domain mapping\",\n        \"Whether latexin directly inhibits AGBL2 catalytic activity or acts via indirect mechanisms is untested\",\n        \"Functional consequence of AGBL2–latexin interaction on tubulin modification not quantified\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrating that AGBL2 overexpression suppresses apoptosis via IRGM-regulated autophagy and activates Aurora A kinase through TPX2 upregulation revealed downstream oncogenic effector pathways beyond tubulin detyrosination.\",\n      \"evidence\": \"Ectopic overexpression and knockdown in HCC cell lines; apoptosis, autophagy flux, and Aurora A kinase activity assays; xenograft tumor models\",\n      \"pmids\": [\"29126912\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether AGBL2 regulates IRGM and TPX2/Aurora A through its carboxypeptidase activity or via a separate function is unclear\",\n        \"Mechanism linking tubulin detyrosination to autophagy induction not established\",\n        \"Single lab study without independent replication\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Observation that AGBL2 enhances AKT phosphorylation and that its pro-tumorigenic effects are partially blocked by parthenolide broadened the signaling outputs of AGBL2 and provided pharmacological validation of its carboxypeptidase activity in cancer.\",\n      \"evidence\": \"AGBL2 knockdown/overexpression in RCC cell lines; parthenolide treatment; AKT phosphorylation by western blot; RNA sequencing\",\n      \"pmids\": [\"39315218\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Direct versus indirect regulation of AKT by AGBL2 is unresolved\",\n        \"Parthenolide is not a specific AGBL2 inhibitor, limiting mechanistic interpretation\",\n        \"Nuclear localization of AGBL2 observed in RCC cells lacks functional characterization\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of AGBL2 catalysis, its full non-tubulin substrate repertoire, the functional significance of its reported nuclear localization, and the precise mechanism by which AGBL2 carboxypeptidase activity connects to downstream signaling pathways (AKT, Aurora A, autophagy) remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No crystal or cryo-EM structure of AGBL2 available\",\n        \"Systematic identification of non-tubulin substrates not performed\",\n        \"Nuclear function of AGBL2 unexplored\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [],\n    \"complexes\": [],\n    \"partners\": [\n      \"RARRES1\",\n      \"LXN\",\n      \"TUBA1A\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}