{"gene":"ADD3","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":1996,"finding":"ADD3 (ADDL) encodes a protein of 674 amino acids with high homology to alpha and beta adducins, suggesting a role in skeletal organization of the cell membrane. The gene was mapped to chromosome 10q24.2-q24.3 by FISH.","method":"cDNA cloning, sequence homology analysis, fluorescence in situ hybridization (FISH)","journal":"Cytogenetics and cell genetics","confidence":"Medium","confidence_rationale":"Tier 2 — direct cloning and chromosomal localization by FISH; single study, foundational characterization","pmids":["8893809"],"is_preprint":false},{"year":2009,"finding":"Genetic deletion of gamma-adducin (Add3) in mice revealed that alpha-adducin stability depends on heterologous binding partners (beta- or gamma-adducin) in a tissue-specific manner: loss of gamma-adducin reduced alpha-adducin by ~70% in platelets, ~50% in spleen and brain, but only ~15% in kidney, while red blood cell parameters remained normal. Double null (beta- and gamma-adducin) mice had barely detectable alpha-adducin, indicating gamma-adducin can partially substitute for beta-adducin.","method":"Targeted gene deletion (knockout mouse), Western blot, hematological analysis, scanning electron microscopy","journal":"American journal of hematology","confidence":"High","confidence_rationale":"Tier 1-2 — clean genetic knockout with multiple orthogonal readouts across tissues; rigorous controls","pmids":["19425068"],"is_preprint":false},{"year":2016,"finding":"Knockdown of Add3 in rat renal afferent arterioles and middle cerebral arteries abolished the myogenic response to pressure elevation (vessels dilated instead of constricted) and increased peak potassium currents ~3-fold in isolated smooth muscle cells, establishing ADD3 as a regulator of potassium channel function and vascular reactivity.","method":"siRNA knockdown (Dicer-substrate DsiRNA), pressurized myograph, patch-clamp electrophysiology","journal":"American journal of physiology. Renal physiology","confidence":"High","confidence_rationale":"Tier 2 — direct loss-of-function with defined cellular and electrophysiological phenotype using two orthogonal functional readouts","pmids":["27927653"],"is_preprint":false},{"year":2017,"finding":"miR-145-5p directly targets the 3'UTR of ADD3 mRNA to repress ADD3 expression; in human hepatic stellate cells (LX-2), miR-145 overexpression decreased ADD3 at both mRNA and protein levels and suppressed p-Akt expression.","method":"Luciferase reporter assay, lentiviral overexpression, qPCR, Western blot","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 — direct 3'UTR reporter assay confirming miR-145-5p as an upstream regulator of ADD3; single lab, multiple methods","pmids":["28902846"],"is_preprint":false},{"year":2018,"finding":"Mutations in ADD3 (encoding gamma-adducin) cause intellectual disability, microcephaly, cataracts and skeletal defects in humans. In Drosophila, ADD3/hts loss-of-function mutants could not be fully rescued by human ADD3 patient variant, confirming pathogenicity. Simultaneous knockdown of ADD3 and KAT2B synergistically impaired kidney and heart function in flies and impaired adhesion/migration of cultured human podocytes, indicating a functional interaction between ADD3 and KAT2B in these tissues.","method":"Drosophila null mutant rescue assays, RNAi knockdown in Drosophila, human podocyte adhesion/migration assays, patient fibroblast protein analysis","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal approaches in fly model and human cells; genetic epistasis and functional cell assays","pmids":["29768408"],"is_preprint":false},{"year":2019,"finding":"circ-ADD3 (a circular RNA derived from ADD3 exons 4-12) reinforces the interaction between CDK1 and EZH2, promoting CDK1-mediated phosphorylation of EZH2 at Thr-345 and Thr-487, leading to increased EZH2 ubiquitination and degradation, which reduces H3K27me3 on promoters of anti-metastatic genes and inhibits HCC cell invasion and metastasis.","method":"Co-immunoprecipitation, in vitro and in vivo invasion/metastasis assays, Western blot, ChIP assay, exogenous overexpression and knockdown","journal":"American journal of cancer research","confidence":"Medium","confidence_rationale":"Tier 2-3 — mechanistic pathway placement via Co-IP and functional assays; single lab but multiple orthogonal methods; pertains to circular RNA derived from ADD3 locus, not ADD3 protein itself","pmids":["31497351"],"is_preprint":false},{"year":2020,"finding":"Loss of ADD3 in glioblastoma cells promoted tumor growth and angiogenesis in vivo, associated with increased PCNA, suppressed p53 and p21 expression, and activation of pro-angiogenic VEGF-VEGFR-2 signaling in endothelial cells. ADD3 function was dependent on cell-matrix interaction.","method":"Knockdown/depletion in GBM cells, in vivo xenograft, Western blot, microarray analysis","journal":"Cancer letters","confidence":"Medium","confidence_rationale":"Tier 2-3 — loss-of-function with defined molecular pathway readouts in vitro and in vivo; single lab","pmids":["31958485"],"is_preprint":false},{"year":2021,"finding":"QKI-5 represses inclusion of ADD3 exon 14 by binding to multiple sites in an upstream intronic region (position-dependent splicing regulation), and this QKI-5-mediated splicing suppression of ADD3 contributes to inhibition of lung cancer cell proliferation and migration.","method":"iCLIP-seq, splicing reporter assays, siRNA knockdown, cell proliferation and migration assays, tumor samples analysis","journal":"Journal of molecular cell biology","confidence":"High","confidence_rationale":"Tier 1-2 — genome-wide binding site mapping by iCLIP-seq combined with functional splicing and cellular assays; multiple orthogonal methods","pmids":["33196842"],"is_preprint":false},{"year":2022,"finding":"Pan-neuronal overexpression or knockdown of the Drosophila ADD3 ortholog (hts) reduced lifespan and impaired locomotion, phenocopying aspects of human ADD3-associated spastic quadriplegic cerebral palsy. Molecular modelling of the human patient variant p.(Gly367Asp) predicted loss of structural integrity of gamma-adducin.","method":"Drosophila gain-of-function and loss-of-function (RNAi), lifespan and locomotion assays, molecular modelling","journal":"Clinical genetics","confidence":"Medium","confidence_rationale":"Tier 2-3 — Drosophila functional model with behavioral readouts; molecular modelling is computational; single study","pmids":["36046955"],"is_preprint":false},{"year":2023,"finding":"The lncRNA SAN acts as a sponge for miR-143-3p, thereby de-repressing ADD3 expression and promoting cellular senescence in adipose-derived stem cells (ASCs). Knockdown of SAN reduced ADD3 expression via releasing miR-143-3p, improving ASC proliferation, migration, and paracrine function.","method":"Dual-luciferase assay, lentiviral overexpression/knockdown, miRNA mimic/inhibitor transfection, EdU, transwell, SA-β-gal assay","journal":"Stem cell research & therapy","confidence":"Medium","confidence_rationale":"Tier 2-3 — luciferase reporter validation of RNA-RNA interaction and rescue experiments; single lab, multiple methods","pmids":["37605290"],"is_preprint":false},{"year":2024,"finding":"ADD3 is necessary and sufficient for maintaining glioblastoma stem cell (GSC) morphology, tumor-tumor connection (TTC/nanotube) abundance, cell cycle progression, and chemoresistance. These effects depend on actin cytoskeleton stability, as ADD3 loss destabilized the actin network.","method":"Knockdown and overexpression in GSCs, live cell imaging, flow cytometry, drug resistance assays, actin cytoskeleton analysis","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 — gain- and loss-of-function with multiple cellular readouts linking ADD3 to actin stability and morphology; single lab","pmids":["39592188"],"is_preprint":false},{"year":2025,"finding":"ADD3 knockout in human pluripotent stem cell-derived cholangiocyte organoids caused defective cholangiocyte differentiation, failure to recruit βII-spectrin to the cell membrane, abnormal primary cilia development, reduced tight junction protein expression, lower transepithelial electrical resistance, and increased paracellular permeability. In Add3 knockout mice with experimental biliary atresia, loss of Add3 increased incidence and severity of BA with elevated bilirubin, liver necrosis/fibrosis, and immune infiltration.","method":"CRISPR knockout of ADD3 in human iPSCs, cholangiocyte organoid differentiation, TEER measurement, immunofluorescence, electron microscopy, mouse BA model (RRV-induced), Western blot","journal":"EBioMedicine","confidence":"High","confidence_rationale":"Tier 1-2 — human organoid KO and mouse KO with multiple orthogonal functional and structural readouts; strong mechanistic evidence across two model systems","pmids":["41297070"],"is_preprint":false},{"year":2026,"finding":"Risk SNPs at the ADD3 locus lie within enhancer elements that drive increased ADD3 expression (demonstrated by allele-specific luciferase assays). Overexpression or morpholino knockdown of the zebrafish add3a ortholog disrupted hepatobiliary development, causing gallbladder hypoplasia/agenesis and reduced intrahepatic bile duct density, phenocopying biliary atresia.","method":"Dual-luciferase enhancer reporter assay, zebrafish mRNA overexpression, morpholino knockdown, in situ hybridization","journal":"Frontiers in genetics","confidence":"Medium","confidence_rationale":"Tier 2 — allele-specific reporter assay plus zebrafish gain- and loss-of-function; single lab, multiple methods","pmids":["41589307"],"is_preprint":false}],"current_model":"ADD3 (gamma-adducin) is a cytoskeletal scaffolding protein that stabilizes alpha-adducin in a tissue-dependent manner, regulates actin cytoskeleton organization and membrane recruitment of βII-spectrin in cholangiocytes, controls potassium channel function and myogenic responses in vascular smooth muscle cells, undergoes alternative splicing regulated by QKI-5 (exon 14 inclusion), and is required for proper bile duct development and barrier integrity—with loss of function causing impaired tight junction assembly, increased paracellular permeability, and susceptibility to biliary atresia."},"narrative":{"teleology":[{"year":1996,"claim":"Identification of ADD3 as a third adducin family member resolved whether the adducin family extended beyond alpha and beta subunits, establishing ADD3 as a candidate membrane-skeleton organizer.","evidence":"cDNA cloning with sequence homology analysis and FISH mapping to 10q24.2-q24.3","pmids":["8893809"],"confidence":"Medium","gaps":["No functional data; role inferred from homology only","Expression pattern across tissues not characterized","Physical interaction with alpha/beta-adducin not demonstrated"]},{"year":2009,"claim":"Genetic knockout revealed that gamma-adducin stabilizes alpha-adducin protein in a tissue-specific manner and can partially substitute for beta-adducin, establishing the first in vivo functional role for ADD3.","evidence":"Add3 knockout mice and Add2/Add3 double knockout mice analyzed by Western blot across tissues and hematological profiling","pmids":["19425068"],"confidence":"High","gaps":["Mechanism of tissue-specific dependence on gamma- versus beta-adducin unknown","Downstream cellular consequences of alpha-adducin loss in affected tissues not explored"]},{"year":2016,"claim":"Demonstrating that ADD3 knockdown abolishes the myogenic response and triples potassium currents in smooth muscle cells established ADD3 as a regulator of ion channel function and vascular tone, extending its role beyond structural scaffolding.","evidence":"siRNA knockdown in rat afferent arterioles and cerebral arteries with pressurized myography and patch-clamp electrophysiology","pmids":["27927653"],"confidence":"High","gaps":["Identity of the potassium channel species regulated by ADD3 not determined","Whether ADD3 acts directly on channels or through actin-cytoskeleton remodeling not resolved"]},{"year":2018,"claim":"Discovery that ADD3 mutations cause a human syndrome of intellectual disability, microcephaly, cataracts, and skeletal defects—validated by Drosophila rescue failure—established ADD3 as a Mendelian disease gene and revealed genetic interaction with KAT2B.","evidence":"Patient variant tested in Drosophila null rescue assay; RNAi epistasis of ADD3/KAT2B in flies and human podocyte functional assays","pmids":["29768408"],"confidence":"High","gaps":["Biochemical basis of ADD3–KAT2B interaction unknown","Whether patient variants affect heterodimer formation with alpha-adducin not tested"]},{"year":2021,"claim":"Identification of QKI-5 as a splicing regulator that represses ADD3 exon 14 inclusion revealed a post-transcriptional control mechanism for ADD3 isoform diversity with functional consequences for cell proliferation.","evidence":"iCLIP-seq mapping of QKI-5 binding sites, splicing reporter assays, and cancer cell proliferation/migration assays","pmids":["33196842"],"confidence":"High","gaps":["Functional difference between ADD3 isoforms with or without exon 14 not biochemically characterized","Whether exon 14 inclusion affects adducin heterodimerization unknown"]},{"year":2024,"claim":"Showing that ADD3 is necessary and sufficient for actin network stability, nanotube formation, and chemoresistance in glioblastoma stem cells defined ADD3 as a cytoskeletal effector in tumor cell connectivity and drug resistance.","evidence":"Knockdown and overexpression in GSCs with live imaging, flow cytometry, and drug resistance assays","pmids":["39592188"],"confidence":"Medium","gaps":["Whether ADD3-dependent nanotubes transfer specific cargo is unknown","Relevance to in vivo GBM progression not established in animal models in this study"]},{"year":2025,"claim":"ADD3 knockout in human cholangiocyte organoids and a mouse biliary atresia model demonstrated that ADD3 is required for βII-spectrin membrane recruitment, tight junction assembly, cilia formation, and biliary epithelial barrier integrity, mechanistically linking ADD3 to biliary atresia susceptibility.","evidence":"CRISPR KO in iPSC-derived cholangiocyte organoids with TEER, immunofluorescence, and electron microscopy; Add3 KO mice challenged with RRV biliary atresia model","pmids":["41297070"],"confidence":"High","gaps":["Whether ADD3 directly binds βII-spectrin or acts indirectly via alpha-adducin not resolved","Role of specific ADD3 isoforms in bile duct development unknown"]},{"year":null,"claim":"The structural basis of ADD3 heterodimer formation, the identity of potassium channels it regulates, and the functional consequences of disease-associated splicing isoforms remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal or cryo-EM structure of gamma-adducin or its heterodimers","Molecular identity of the K+ channel target in vascular smooth muscle unknown","Functional distinction of exon 14-inclusive versus exon 14-skipped isoforms not biochemically defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[1,2,10,11]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[1,11]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,11]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[10,11]},{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[11]}],"pathway":[{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[4,11,12]},{"term_id":"R-HSA-1500931","term_label":"Cell-Cell communication","supporting_discovery_ids":[10,11]}],"complexes":["adducin heterodimer (alpha/gamma-adducin)"],"partners":["ADD1","ADD2","KAT2B","SPTBN1"],"other_free_text":[]},"mechanistic_narrative":"ADD3 (gamma-adducin) is a cytoskeletal scaffolding protein that stabilizes the spectrin-actin membrane skeleton and regulates diverse tissue-specific processes including vascular reactivity, bile duct development, and neuronal function. ADD3 forms obligate heterodimers with alpha-adducin in a tissue-dependent manner—its loss reduces alpha-adducin protein levels by up to 70% in platelets and brain—and it recruits βII-spectrin to the plasma membrane, maintains tight junctions, and stabilizes actin networks in cholangiocytes and glioblastoma stem cells [PMID:19425068, PMID:41297070, PMID:39592188]. In vascular smooth muscle, ADD3 constrains potassium channel activity and is required for the myogenic vasoconstrictor response [PMID:27927653]. Loss-of-function mutations in ADD3 cause a syndromic disorder featuring intellectual disability, microcephaly, cataracts, and skeletal defects, and ADD3 knockout increases susceptibility to biliary atresia in mouse and human organoid models [PMID:29768408, PMID:41297070]."},"prefetch_data":{"uniprot":{"accession":"Q9UEY8","full_name":"Gamma-adducin","aliases":["Adducin-like protein 70"],"length_aa":706,"mass_kda":79.2,"function":"Membrane-cytoskeleton-associated protein that promotes the assembly of the spectrin-actin network. Plays a role in actin filament capping (PubMed:23836506). Binds to calmodulin (Probable). Involved in myogenic reactivity of the renal afferent arteriole (Af-art), renal interlobular arteries and middle cerebral artery (MCA) to increased perfusion pressure. Involved in regulation of potassium channels in the vascular smooth muscle cells (VSMCs) of the Af-art and MCA ex vivo. Involved in regulation of glomerular capillary pressure, glomerular filtration rate (GFR) and glomerular nephrin expression in response to hypertension. Involved in renal blood flow (RBF) autoregulation. Plays a role in podocyte structure and function. Regulates globular monomer actin (G-actin) and filamentous polymer actin (F-actin) ratios in the primary podocytes affecting actin cytoskeleton organization. Regulates expression of synaptopodin, RhoA, Rac1 and CDC42 in the renal cortex and the primary podocytes. Regulates expression of nephrin in the glomeruli and in the primary podocytes, expression of nephrin and podocinin in the renal cortex, and expression of focal adhesion proteins integrin alpha-3 and integrin beta-1 in the glomeruli. Involved in cell migration and cell adhesion of podocytes, and in podocyte foot process effacement. Regulates expression of profibrotics markers MMP2, MMP9, TGF beta-1, tubular tight junction protein E-cadherin, and mesenchymal markers vimentin and alpha-SMA (By similarity). Promotes the growth of neurites (By similarity)","subcellular_location":"Cytoplasm, cytoskeleton; Cell membrane; Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q9UEY8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ADD3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"ACTG1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/ADD3","total_profiled":1310},"omim":[{"mim_id":"617008","title":"CEREBRAL PALSY, SPASTIC QUADRIPLEGIC, 3; CPSQ3","url":"https://www.omim.org/entry/617008"},{"mim_id":"612900","title":"CEREBRAL PALSY, SPASTIC QUADRIPLEGIC, 2; CPSQ2","url":"https://www.omim.org/entry/612900"},{"mim_id":"602303","title":"LYSINE ACETYLTRANSFERASE 2B; KAT2B","url":"https://www.omim.org/entry/602303"},{"mim_id":"601568","title":"ADDUCIN 3; ADD3","url":"https://www.omim.org/entry/601568"},{"mim_id":"601021","title":"NUCLEOPORIN, 98-KD; NUP98","url":"https://www.omim.org/entry/601021"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Plasma membrane","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ADD3"},"hgnc":{"alias_symbol":[],"prev_symbol":["ADDL"]},"alphafold":{"accession":"Q9UEY8","domains":[{"cath_id":"-","chopping":"34-102","consensus_level":"medium","plddt":77.3152,"start":34,"end":102},{"cath_id":"3.40.225.10","chopping":"127-382","consensus_level":"high","plddt":89.1636,"start":127,"end":382}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UEY8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UEY8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UEY8-F1-predicted_aligned_error_v6.png","plddt_mean":66.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ADD3","jax_strain_url":"https://www.jax.org/strain/search?query=ADD3"},"sequence":{"accession":"Q9UEY8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UEY8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UEY8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UEY8"}},"corpus_meta":[{"pmid":"31497351","id":"PMC_31497351","title":"Circular RNA circ-ADD3 inhibits hepatocellular carcinoma metastasis through facilitating EZH2 degradation via CDK1-mediated ubiquitination.","date":"2019","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/31497351","citation_count":63,"is_preprint":false},{"pmid":"24104524","id":"PMC_24104524","title":"Replication of a GWAS signal in a Caucasian population implicates ADD3 in susceptibility to biliary atresia.","date":"2013","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24104524","citation_count":53,"is_preprint":false},{"pmid":"33196842","id":"PMC_33196842","title":"QKI-5 regulates the alternative splicing of cytoskeletal gene ADD3 in lung cancer.","date":"2021","source":"Journal of molecular cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/33196842","citation_count":41,"is_preprint":false},{"pmid":"27927653","id":"PMC_27927653","title":"Knockdown of Add3 impairs the myogenic response of renal afferent arterioles and middle cerebral arteries.","date":"2016","source":"American journal of physiology. Renal physiology","url":"https://pubmed.ncbi.nlm.nih.gov/27927653","citation_count":40,"is_preprint":false},{"pmid":"28902846","id":"PMC_28902846","title":"Downregulation of microRNA-145 may contribute to liver fibrosis in biliary atresia by targeting ADD3.","date":"2017","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/28902846","citation_count":29,"is_preprint":false},{"pmid":"25285724","id":"PMC_25285724","title":"Association between single nucleotide polymorphisms in the ADD3 gene and susceptibility to biliary atresia.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25285724","citation_count":23,"is_preprint":false},{"pmid":"31958485","id":"PMC_31958485","title":"Loss of cytoskeleton protein ADD3 promotes tumor growth and angiogenesis in glioblastoma multiforme.","date":"2020","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/31958485","citation_count":21,"is_preprint":false},{"pmid":"29768408","id":"PMC_29768408","title":"A homozygous KAT2B variant modulates the clinical phenotype of ADD3 deficiency in humans and flies.","date":"2018","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/29768408","citation_count":20,"is_preprint":false},{"pmid":"32315284","id":"PMC_32315284","title":"Association of common variation in ADD3 and GPC1 with biliary atresia susceptibility.","date":"2020","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/32315284","citation_count":18,"is_preprint":false},{"pmid":"8893809","id":"PMC_8893809","title":"Cloning, expression and chromosome mapping of adducin-like 70 (ADDL), a human cDNA highly homologous to human erythrocyte adducin.","date":"1996","source":"Cytogenetics and cell genetics","url":"https://pubmed.ncbi.nlm.nih.gov/8893809","citation_count":18,"is_preprint":false},{"pmid":"37605290","id":"PMC_37605290","title":"Knockdown of long noncoding RNA SAN rejuvenates aged adipose-derived stem cells via miR-143-3p/ADD3 axis.","date":"2023","source":"Stem cell research & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/37605290","citation_count":14,"is_preprint":false},{"pmid":"19425068","id":"PMC_19425068","title":"Targeted deletion of the gamma-adducin gene (Add3) in mice reveals differences in alpha-adducin interactions in erythroid and nonerythroid cells.","date":"2009","source":"American journal of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/19425068","citation_count":14,"is_preprint":false},{"pmid":"37834180","id":"PMC_37834180","title":"Contribution of ADD3 and the HLA Genes to Biliary Atresia Risk in Chinese.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37834180","citation_count":10,"is_preprint":false},{"pmid":"36046955","id":"PMC_36046955","title":"Hereditary spastic paraparesis presenting as cerebral palsy due to ADD3 variant with mechanistic insight provided by a Drosophila γ-adducin model.","date":"2022","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36046955","citation_count":8,"is_preprint":false},{"pmid":"34970477","id":"PMC_34970477","title":"ADD3 Deletion in Glioblastoma Predicts Disease Status and Survival.","date":"2021","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/34970477","citation_count":5,"is_preprint":false},{"pmid":"10051165","id":"PMC_10051165","title":"De novo mosaic add(3) characterized to be trisomy 14q31-qter using spectral karyotyping and subtelomeric probes.","date":"1999","source":"American journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10051165","citation_count":4,"is_preprint":false},{"pmid":"39592188","id":"PMC_39592188","title":"Morphoregulatory ADD3 underlies glioblastoma growth and formation of tumor-tumor connections.","date":"2024","source":"Life science alliance","url":"https://pubmed.ncbi.nlm.nih.gov/39592188","citation_count":1,"is_preprint":false},{"pmid":"41589307","id":"PMC_41589307","title":"Multiple susceptibility enhancer variants increasing ADD3 expression predisposes to biliary atresia risk.","date":"2026","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/41589307","citation_count":0,"is_preprint":false},{"pmid":"41297070","id":"PMC_41297070","title":"Loss of function of Adducin 3 (ADD3) causes abnormal development and impaired barrier function of human and mouse bile duct cells resulting in increased incidence and severity of Biliary Atresia.","date":"2025","source":"EBioMedicine","url":"https://pubmed.ncbi.nlm.nih.gov/41297070","citation_count":0,"is_preprint":false},{"pmid":"41168449","id":"PMC_41168449","title":"Venetoclax-based chemotherapy failure in adult T-cell acute lymphoblastic leukemia with NUP98::ADD3 fusion: a case report.","date":"2025","source":"Annals of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/41168449","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11252,"output_tokens":3236,"usd":0.041148},"stage2":{"model":"claude-opus-4-6","input_tokens":6610,"output_tokens":2031,"usd":0.125738},"total_usd":0.166886,"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\": 1996,\n      \"finding\": \"ADD3 (ADDL) encodes a protein of 674 amino acids with high homology to alpha and beta adducins, suggesting a role in skeletal organization of the cell membrane. The gene was mapped to chromosome 10q24.2-q24.3 by FISH.\",\n      \"method\": \"cDNA cloning, sequence homology analysis, fluorescence in situ hybridization (FISH)\",\n      \"journal\": \"Cytogenetics and cell genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct cloning and chromosomal localization by FISH; single study, foundational characterization\",\n      \"pmids\": [\"8893809\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Genetic deletion of gamma-adducin (Add3) in mice revealed that alpha-adducin stability depends on heterologous binding partners (beta- or gamma-adducin) in a tissue-specific manner: loss of gamma-adducin reduced alpha-adducin by ~70% in platelets, ~50% in spleen and brain, but only ~15% in kidney, while red blood cell parameters remained normal. Double null (beta- and gamma-adducin) mice had barely detectable alpha-adducin, indicating gamma-adducin can partially substitute for beta-adducin.\",\n      \"method\": \"Targeted gene deletion (knockout mouse), Western blot, hematological analysis, scanning electron microscopy\",\n      \"journal\": \"American journal of hematology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — clean genetic knockout with multiple orthogonal readouts across tissues; rigorous controls\",\n      \"pmids\": [\"19425068\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Knockdown of Add3 in rat renal afferent arterioles and middle cerebral arteries abolished the myogenic response to pressure elevation (vessels dilated instead of constricted) and increased peak potassium currents ~3-fold in isolated smooth muscle cells, establishing ADD3 as a regulator of potassium channel function and vascular reactivity.\",\n      \"method\": \"siRNA knockdown (Dicer-substrate DsiRNA), pressurized myograph, patch-clamp electrophysiology\",\n      \"journal\": \"American journal of physiology. Renal physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct loss-of-function with defined cellular and electrophysiological phenotype using two orthogonal functional readouts\",\n      \"pmids\": [\"27927653\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"miR-145-5p directly targets the 3'UTR of ADD3 mRNA to repress ADD3 expression; in human hepatic stellate cells (LX-2), miR-145 overexpression decreased ADD3 at both mRNA and protein levels and suppressed p-Akt expression.\",\n      \"method\": \"Luciferase reporter assay, lentiviral overexpression, qPCR, Western blot\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct 3'UTR reporter assay confirming miR-145-5p as an upstream regulator of ADD3; single lab, multiple methods\",\n      \"pmids\": [\"28902846\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Mutations in ADD3 (encoding gamma-adducin) cause intellectual disability, microcephaly, cataracts and skeletal defects in humans. In Drosophila, ADD3/hts loss-of-function mutants could not be fully rescued by human ADD3 patient variant, confirming pathogenicity. Simultaneous knockdown of ADD3 and KAT2B synergistically impaired kidney and heart function in flies and impaired adhesion/migration of cultured human podocytes, indicating a functional interaction between ADD3 and KAT2B in these tissues.\",\n      \"method\": \"Drosophila null mutant rescue assays, RNAi knockdown in Drosophila, human podocyte adhesion/migration assays, patient fibroblast protein analysis\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal approaches in fly model and human cells; genetic epistasis and functional cell assays\",\n      \"pmids\": [\"29768408\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"circ-ADD3 (a circular RNA derived from ADD3 exons 4-12) reinforces the interaction between CDK1 and EZH2, promoting CDK1-mediated phosphorylation of EZH2 at Thr-345 and Thr-487, leading to increased EZH2 ubiquitination and degradation, which reduces H3K27me3 on promoters of anti-metastatic genes and inhibits HCC cell invasion and metastasis.\",\n      \"method\": \"Co-immunoprecipitation, in vitro and in vivo invasion/metastasis assays, Western blot, ChIP assay, exogenous overexpression and knockdown\",\n      \"journal\": \"American journal of cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — mechanistic pathway placement via Co-IP and functional assays; single lab but multiple orthogonal methods; pertains to circular RNA derived from ADD3 locus, not ADD3 protein itself\",\n      \"pmids\": [\"31497351\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Loss of ADD3 in glioblastoma cells promoted tumor growth and angiogenesis in vivo, associated with increased PCNA, suppressed p53 and p21 expression, and activation of pro-angiogenic VEGF-VEGFR-2 signaling in endothelial cells. ADD3 function was dependent on cell-matrix interaction.\",\n      \"method\": \"Knockdown/depletion in GBM cells, in vivo xenograft, Western blot, microarray analysis\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — loss-of-function with defined molecular pathway readouts in vitro and in vivo; single lab\",\n      \"pmids\": [\"31958485\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"QKI-5 represses inclusion of ADD3 exon 14 by binding to multiple sites in an upstream intronic region (position-dependent splicing regulation), and this QKI-5-mediated splicing suppression of ADD3 contributes to inhibition of lung cancer cell proliferation and migration.\",\n      \"method\": \"iCLIP-seq, splicing reporter assays, siRNA knockdown, cell proliferation and migration assays, tumor samples analysis\",\n      \"journal\": \"Journal of molecular cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — genome-wide binding site mapping by iCLIP-seq combined with functional splicing and cellular assays; multiple orthogonal methods\",\n      \"pmids\": [\"33196842\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Pan-neuronal overexpression or knockdown of the Drosophila ADD3 ortholog (hts) reduced lifespan and impaired locomotion, phenocopying aspects of human ADD3-associated spastic quadriplegic cerebral palsy. Molecular modelling of the human patient variant p.(Gly367Asp) predicted loss of structural integrity of gamma-adducin.\",\n      \"method\": \"Drosophila gain-of-function and loss-of-function (RNAi), lifespan and locomotion assays, molecular modelling\",\n      \"journal\": \"Clinical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — Drosophila functional model with behavioral readouts; molecular modelling is computational; single study\",\n      \"pmids\": [\"36046955\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"The lncRNA SAN acts as a sponge for miR-143-3p, thereby de-repressing ADD3 expression and promoting cellular senescence in adipose-derived stem cells (ASCs). Knockdown of SAN reduced ADD3 expression via releasing miR-143-3p, improving ASC proliferation, migration, and paracrine function.\",\n      \"method\": \"Dual-luciferase assay, lentiviral overexpression/knockdown, miRNA mimic/inhibitor transfection, EdU, transwell, SA-β-gal assay\",\n      \"journal\": \"Stem cell research & therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — luciferase reporter validation of RNA-RNA interaction and rescue experiments; single lab, multiple methods\",\n      \"pmids\": [\"37605290\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ADD3 is necessary and sufficient for maintaining glioblastoma stem cell (GSC) morphology, tumor-tumor connection (TTC/nanotube) abundance, cell cycle progression, and chemoresistance. These effects depend on actin cytoskeleton stability, as ADD3 loss destabilized the actin network.\",\n      \"method\": \"Knockdown and overexpression in GSCs, live cell imaging, flow cytometry, drug resistance assays, actin cytoskeleton analysis\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain- and loss-of-function with multiple cellular readouts linking ADD3 to actin stability and morphology; single lab\",\n      \"pmids\": [\"39592188\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ADD3 knockout in human pluripotent stem cell-derived cholangiocyte organoids caused defective cholangiocyte differentiation, failure to recruit βII-spectrin to the cell membrane, abnormal primary cilia development, reduced tight junction protein expression, lower transepithelial electrical resistance, and increased paracellular permeability. In Add3 knockout mice with experimental biliary atresia, loss of Add3 increased incidence and severity of BA with elevated bilirubin, liver necrosis/fibrosis, and immune infiltration.\",\n      \"method\": \"CRISPR knockout of ADD3 in human iPSCs, cholangiocyte organoid differentiation, TEER measurement, immunofluorescence, electron microscopy, mouse BA model (RRV-induced), Western blot\",\n      \"journal\": \"EBioMedicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — human organoid KO and mouse KO with multiple orthogonal functional and structural readouts; strong mechanistic evidence across two model systems\",\n      \"pmids\": [\"41297070\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Risk SNPs at the ADD3 locus lie within enhancer elements that drive increased ADD3 expression (demonstrated by allele-specific luciferase assays). Overexpression or morpholino knockdown of the zebrafish add3a ortholog disrupted hepatobiliary development, causing gallbladder hypoplasia/agenesis and reduced intrahepatic bile duct density, phenocopying biliary atresia.\",\n      \"method\": \"Dual-luciferase enhancer reporter assay, zebrafish mRNA overexpression, morpholino knockdown, in situ hybridization\",\n      \"journal\": \"Frontiers in genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — allele-specific reporter assay plus zebrafish gain- and loss-of-function; single lab, multiple methods\",\n      \"pmids\": [\"41589307\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ADD3 (gamma-adducin) is a cytoskeletal scaffolding protein that stabilizes alpha-adducin in a tissue-dependent manner, regulates actin cytoskeleton organization and membrane recruitment of βII-spectrin in cholangiocytes, controls potassium channel function and myogenic responses in vascular smooth muscle cells, undergoes alternative splicing regulated by QKI-5 (exon 14 inclusion), and is required for proper bile duct development and barrier integrity—with loss of function causing impaired tight junction assembly, increased paracellular permeability, and susceptibility to biliary atresia.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ADD3 (gamma-adducin) is a cytoskeletal scaffolding protein that stabilizes the spectrin-actin membrane skeleton and regulates diverse tissue-specific processes including vascular reactivity, bile duct development, and neuronal function. ADD3 forms obligate heterodimers with alpha-adducin in a tissue-dependent manner—its loss reduces alpha-adducin protein levels by up to 70% in platelets and brain—and it recruits βII-spectrin to the plasma membrane, maintains tight junctions, and stabilizes actin networks in cholangiocytes and glioblastoma stem cells [PMID:19425068, PMID:41297070, PMID:39592188]. In vascular smooth muscle, ADD3 constrains potassium channel activity and is required for the myogenic vasoconstrictor response [PMID:27927653]. Loss-of-function mutations in ADD3 cause a syndromic disorder featuring intellectual disability, microcephaly, cataracts, and skeletal defects, and ADD3 knockout increases susceptibility to biliary atresia in mouse and human organoid models [PMID:29768408, PMID:41297070].\",\n  \"teleology\": [\n    {\n      \"year\": 1996,\n      \"claim\": \"Identification of ADD3 as a third adducin family member resolved whether the adducin family extended beyond alpha and beta subunits, establishing ADD3 as a candidate membrane-skeleton organizer.\",\n      \"evidence\": \"cDNA cloning with sequence homology analysis and FISH mapping to 10q24.2-q24.3\",\n      \"pmids\": [\"8893809\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional data; role inferred from homology only\", \"Expression pattern across tissues not characterized\", \"Physical interaction with alpha/beta-adducin not demonstrated\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Genetic knockout revealed that gamma-adducin stabilizes alpha-adducin protein in a tissue-specific manner and can partially substitute for beta-adducin, establishing the first in vivo functional role for ADD3.\",\n      \"evidence\": \"Add3 knockout mice and Add2/Add3 double knockout mice analyzed by Western blot across tissues and hematological profiling\",\n      \"pmids\": [\"19425068\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of tissue-specific dependence on gamma- versus beta-adducin unknown\", \"Downstream cellular consequences of alpha-adducin loss in affected tissues not explored\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstrating that ADD3 knockdown abolishes the myogenic response and triples potassium currents in smooth muscle cells established ADD3 as a regulator of ion channel function and vascular tone, extending its role beyond structural scaffolding.\",\n      \"evidence\": \"siRNA knockdown in rat afferent arterioles and cerebral arteries with pressurized myography and patch-clamp electrophysiology\",\n      \"pmids\": [\"27927653\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the potassium channel species regulated by ADD3 not determined\", \"Whether ADD3 acts directly on channels or through actin-cytoskeleton remodeling not resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Discovery that ADD3 mutations cause a human syndrome of intellectual disability, microcephaly, cataracts, and skeletal defects—validated by Drosophila rescue failure—established ADD3 as a Mendelian disease gene and revealed genetic interaction with KAT2B.\",\n      \"evidence\": \"Patient variant tested in Drosophila null rescue assay; RNAi epistasis of ADD3/KAT2B in flies and human podocyte functional assays\",\n      \"pmids\": [\"29768408\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Biochemical basis of ADD3–KAT2B interaction unknown\", \"Whether patient variants affect heterodimer formation with alpha-adducin not tested\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identification of QKI-5 as a splicing regulator that represses ADD3 exon 14 inclusion revealed a post-transcriptional control mechanism for ADD3 isoform diversity with functional consequences for cell proliferation.\",\n      \"evidence\": \"iCLIP-seq mapping of QKI-5 binding sites, splicing reporter assays, and cancer cell proliferation/migration assays\",\n      \"pmids\": [\"33196842\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional difference between ADD3 isoforms with or without exon 14 not biochemically characterized\", \"Whether exon 14 inclusion affects adducin heterodimerization unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showing that ADD3 is necessary and sufficient for actin network stability, nanotube formation, and chemoresistance in glioblastoma stem cells defined ADD3 as a cytoskeletal effector in tumor cell connectivity and drug resistance.\",\n      \"evidence\": \"Knockdown and overexpression in GSCs with live imaging, flow cytometry, and drug resistance assays\",\n      \"pmids\": [\"39592188\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ADD3-dependent nanotubes transfer specific cargo is unknown\", \"Relevance to in vivo GBM progression not established in animal models in this study\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"ADD3 knockout in human cholangiocyte organoids and a mouse biliary atresia model demonstrated that ADD3 is required for βII-spectrin membrane recruitment, tight junction assembly, cilia formation, and biliary epithelial barrier integrity, mechanistically linking ADD3 to biliary atresia susceptibility.\",\n      \"evidence\": \"CRISPR KO in iPSC-derived cholangiocyte organoids with TEER, immunofluorescence, and electron microscopy; Add3 KO mice challenged with RRV biliary atresia model\",\n      \"pmids\": [\"41297070\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ADD3 directly binds βII-spectrin or acts indirectly via alpha-adducin not resolved\", \"Role of specific ADD3 isoforms in bile duct development unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of ADD3 heterodimer formation, the identity of potassium channels it regulates, and the functional consequences of disease-associated splicing isoforms remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal or cryo-EM structure of gamma-adducin or its heterodimers\", \"Molecular identity of the K+ channel target in vascular smooth muscle unknown\", \"Functional distinction of exon 14-inclusive versus exon 14-skipped isoforms not biochemically defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [1, 2, 10, 11]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [1, 11]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 11]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [10, 11]},\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [4, 11, 12]},\n      {\"term_id\": \"R-HSA-1500931\", \"supporting_discovery_ids\": [10, 11]}\n    ],\n    \"complexes\": [\n      \"adducin heterodimer (alpha/gamma-adducin)\"\n    ],\n    \"partners\": [\n      \"ADD1\",\n      \"ADD2\",\n      \"KAT2B\",\n      \"SPTBN1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}