{"gene":"ARRDC3","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":2010,"finding":"ARRDC3 directly binds to a phosphorylated form of integrin beta-4 (ITGβ4), leading to its internalization, ubiquitination, and degradation, thereby suppressing breast cancer cell proliferation, migration, and invasion.","method":"Co-immunoprecipitation, overexpression/knockdown with functional phenotypic readouts (proliferation, migration, invasion, soft agar, xenograft)","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP plus multiple orthogonal functional assays, foundational study with 98 citations","pmids":["20603614"],"is_preprint":false},{"year":2013,"finding":"ARRDC3 recruits the NEDD4-family E3 ubiquitin ligase NEDD4 via two C-terminal PPXY motifs; the highest-affinity interaction is between ARRDC3 PPXY1 and NEDD4 WW3 domain (Kd ~3 μM), while avid binding of full-length proteins is driven by bivalent engagement of WW2-WW3 or WW3-WW4 combinations (Kd ~300 nM); crystal structures of uncomplexed and PPXY1-bound WW3 at 1.1 and 1.7 Å revealed conformational changes and the hydrogen-bonding network, with Val-352' in a 310 helix being critical for high-affinity binding.","method":"ITC binding assays, X-ray crystallography (1.1 and 1.7 Å), mutagenesis, Co-IP in HEK293 cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — crystal structures with mutagenesis and in vitro binding assays in a single rigorous study","pmids":["24379409"],"is_preprint":false},{"year":2014,"finding":"Crystal structures of the N-terminal lobe of human ARRDC3 at 1.73 and 2.8 Å revealed a large electropositive region; residues within this basic patch were shown to be important for binding to β2-adrenergic receptor (β2AR), paralleling receptor recognition by β-arrestins.","method":"X-ray crystallography, mutagenesis, binding assays","journal":"Protein science","confidence":"High","confidence_rationale":"Tier 1 — crystal structures with mutagenesis validation of receptor-binding residues","pmids":["25220262"],"is_preprint":false},{"year":2015,"finding":"ARRDC3 colocalizes with ALIX at late endosomes and is required for ALIX ubiquitination (mediated by NEDD4-family ligase WWP2, which interacts with ARRDC3 but not ALIX), ALIX interaction with activated PAR1 and CHMP4B ESCRT-III, and subsequent lysosomal degradation of protease-activated receptor-1 (PAR1).","method":"siRNA depletion, Co-IP, immunofluorescence colocalization, E3 ligase screen (9 NEDD4-family members)","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP, systematic ligase screen, and colocalization with functional consequence, replicated in subsequent studies","pmids":["26490116"],"is_preprint":false},{"year":2016,"finding":"ARRDC3 localizes primarily to EEA1-positive early endosomes, directly interacts with β2AR in a ligand-independent manner, negatively regulates β2AR entry into SNX27-occupied endosomal tubules, thereby delaying receptor recycling and increasing β2AR-dependent endosomal signaling.","method":"Confocal immunofluorescence, Co-IP, ARRDC3 overexpression/knockdown, live-cell imaging of endosomal tubules, cAMP signaling assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — direct localization experiments tied to functional consequences with multiple orthogonal methods","pmids":["27226565"],"is_preprint":false},{"year":2018,"finding":"ARRDC3 acts as a tumor suppressor in breast carcinoma by restoring lysosomal degradation of PAR1 through the ALIX-dependent pathway, attenuating persistent PAR1-stimulated JNK signaling, and thereby reducing breast carcinoma invasion.","method":"Lentiviral doxycycline-inducible re-expression, flow cytometry/trafficking assays, JNK inhibition, invasion assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — clean re-expression system with defined trafficking and signaling readouts, multiple orthogonal methods","pmids":["29348172"],"is_preprint":false},{"year":2018,"finding":"ARRDC3 interacts with YAP1 via its PPXY motifs (binding to YAP1 WW domains) and facilitates Itch E3 ubiquitin ligase-mediated ubiquitination and degradation of YAP1, suppressing Hippo pathway activation in clear cell renal cell carcinoma.","method":"Tandem affinity purification/mass spectrometry, Co-IP, shRNA knockdown, mutagenesis of PPXY motifs, ubiquitination assays","journal":"American journal of cancer research","confidence":"High","confidence_rationale":"Tier 2 — MS-based interactome discovery confirmed by Co-IP with domain mapping and functional ubiquitination assays","pmids":["29416926"],"is_preprint":false},{"year":2018,"finding":"ARRDC3 binds and decreases expression of the oncoprotein YAP, promoting its lysosome-mediated degradation, thereby suppressing colorectal cancer progression; this regulation of the Hippo pathway by ARRDC3 is conserved from Drosophila to mammals.","method":"Co-IP, overexpression/knockdown, lysosome inhibitor assays, Drosophila genetic analysis","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP with functional KD/OE and pathway validation, but single lab study","pmids":["29364502"],"is_preprint":false},{"year":2020,"finding":"ARRDC3 directly interacts with the insulin receptor (IR) and is phosphorylated by IR on a conserved tyrosine residue Y382 in its carboxyl-terminal domain; this interaction promotes IR internalization, and liver-specific knockout of Arrdc3 increases IR at the plasma membrane, enhancing hepatic insulin sensitivity with increased FOXO1 phosphorylation, reduced PEPCK, and increased glucokinase expression.","method":"Liver-specific knockout mice, euglycemic-hyperinsulinemic clamps, Co-IP, plasma membrane fractionation, phospho-Western blotting, mutagenesis (Y382)","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with defined metabolic phenotype, Co-IP, mutagenesis of phosphorylation site, multiple orthogonal methods","pmids":["32156724"],"is_preprint":false},{"year":2021,"finding":"ARRDC3 suppresses PAR1-induced Hippo signaling by sequestering the transcriptional co-activator TAZ, independently of ARRDC3-regulated PAR1 trafficking; the ARRDC3 C-terminal PPXY motifs and TAZ WW domain are crucial for this interaction, which suppresses TNBC migration and lung metastasis in vivo.","method":"Co-IP, PPXY motif mutagenesis, siRNA depletion, migration/invasion assays, in vivo lung metastasis model","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — Co-IP with domain mapping, in vivo validation, multiple orthogonal functional assays","pmids":["33722977"],"is_preprint":false},{"year":2023,"finding":"Ubiquitination of ARRDC3, mediated primarily through its two C-terminal PPXY motifs, regulates ARRDC3 protein degradation, dictates its subcellular localization, controls its interaction with WWP2, and is essential for ARRDC3-dependent GPCR trafficking and signaling.","method":"Mutagenesis of PPXY motifs, ubiquitination assays, Co-IP, subcellular fractionation/imaging, GPCR trafficking assays","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1-2 — mutagenesis combined with multiple orthogonal functional and localization assays","pmids":["37223976"],"is_preprint":false},{"year":2024,"finding":"ARRDC3 interacts with receptor tyrosine kinase AXL and promotes its ubiquitination and degradation, negatively regulating downstream Akt and ERK phosphorylation; ARRDC3 deficiency decreases sunitinib sensitivity of ccRCC cells in an AXL stability-dependent manner.","method":"Co-IP with wildtype and mutant proteins, CRISPR-Cas9 ARRDC3 knockout, ubiquitination assays, pharmacological experiments, immunohistochemistry","journal":"Cell cycle","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP with CRISPR KO and functional drug sensitivity assays, single lab study","pmids":["38389126"],"is_preprint":false},{"year":2025,"finding":"ARRDC3 contains a novel phosphorylation site at tyrosine Y394 embedded in the C-terminal PPxY motif that functions as a phospho-regulatory switch: Y394 phosphorylation promotes interaction with c-Src via its SH2 domain and enables regulation of c-Src activity, whereas the non-phosphorylated form binds WWP2; Y394 phosphorylation disrupts WWP2 interaction and perturbs ARRDC3-dependent lysosomal trafficking of PAR1.","method":"Mutagenesis (Y394), Co-IP, SH2 domain binding assays, GPCR trafficking assays, c-Src activity assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — mutagenesis of phosphorylation site with multiple orthogonal functional readouts showing divergent binding partner selection","pmids":["40409556"],"is_preprint":false},{"year":2014,"finding":"SIRT2, a class III HDAC, epigenetically silences ARRDC3 expression in basal-like breast cancer cells by binding to the ARRDC3 promoter and reducing histone acetylation at that locus; inhibitors of class III HDACs restore ARRDC3 expression.","method":"Chromatin immunoprecipitation (ChIP), HDAC inhibitor treatment, qRT-PCR, Western blotting","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP establishes SIRT2 binding at ARRDC3 promoter with functional inhibitor rescue, single lab","pmids":["24457910"],"is_preprint":false},{"year":2025,"finding":"ARRDC3 promotes lysosomal degradation of YAP, and this mechanism inhibits enterovirus (EV-D68, EV-A71) replication; YAP facilitates enterovirus replication by suppressing the interferon pathway independently of its transcriptional activity, and the ARRDC3-YAP axis also exerts broad-spectrum antiviral effects against HPIV3 and VSV.","method":"Overexpression/knockdown of ARRDC3 and YAP, lysosomal pathway inhibition, interferon pathway reporter assays, viral replication assays","journal":"Virologica Sinica","confidence":"Medium","confidence_rationale":"Tier 2 — functional KD/OE with defined pathway (lysosomal YAP degradation) and multiple virus models, single lab","pmids":["40701343"],"is_preprint":false},{"year":2017,"finding":"Adipocyte-specific deletion of Arrdc3 increases UCP1 expression in subcutaneous and parametrial white adipose tissue, but this effect is independent of canonical β-adrenergic receptor signaling, as Arrdc3-null adipocytes show decreased UCP1 levels in response to β-adrenergic agonist.","method":"Conditional adipocyte-specific Arrdc3 knockout mice, in vitro β-adrenergic stimulation assays, Western blotting for UCP1 and signaling proteins, metabolic phenotyping","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 — genetic KO with defined cellular phenotype and mechanistic exclusion of canonical pathway, single lab","pmids":["28291835"],"is_preprint":false},{"year":2025,"finding":"ARRDC3 upregulation in ischemic neurons promotes Drp1-dependent mitochondrial fragmentation and neuronal ferroptosis; this pathway is suppressed by exosomal CRYAB, which reduces ARRDC3 expression.","method":"Transcriptomic analysis, overexpression/knockdown of ARRDC3 and Drp1, ferroptosis assays, MCAO/R mouse model","journal":"Advanced healthcare materials","confidence":"Low","confidence_rationale":"Tier 3 — functional KD/OE with phenotypic readout but limited direct mechanistic validation of ARRDC3-Drp1 interaction","pmids":["41555725"],"is_preprint":false}],"current_model":"ARRDC3 is a multifunctional α-arrestin adaptor protein that recruits NEDD4-family E3 ubiquitin ligases (NEDD4, WWP2, Itch) via its C-terminal PPXY motifs to promote ubiquitination and lysosomal or proteasomal degradation of target proteins including ITGβ4, β2AR, PAR1 (via ALIX), YAP/TAZ, AXL, and the insulin receptor; its scaffolding functions are regulated by phosphorylation (Y382 by insulin receptor, Y394 as a switch between c-Src SH2 vs. WWP2 binding) and by its own ubiquitination status, while its subcellular localization to early endosomes positions it to control GPCR endosomal residence time, recycling, and downstream signaling."},"narrative":{"teleology":[{"year":2010,"claim":"The initial identification of ARRDC3 as a functional adaptor established that it directly binds phosphorylated integrin β4, promoting its internalization and degradation, thereby revealing ARRDC3 as a tumor-suppressive regulator of receptor turnover.","evidence":"Co-immunoprecipitation, overexpression/knockdown with proliferation, migration, invasion, and xenograft assays in breast cancer cells","pmids":["20603614"],"confidence":"High","gaps":["Mechanism of ITGβ4 ubiquitination (which E3 ligase) was not identified","Whether ARRDC3 PPXY motifs mediate ligase recruitment in this context was unknown"]},{"year":2013,"claim":"Structural and biophysical dissection of the ARRDC3–NEDD4 interaction defined the molecular basis for E3 ligase recruitment: bivalent engagement of two PPXY motifs with NEDD4 WW domains achieves ~300 nM affinity, establishing the mechanistic framework for ARRDC3's adaptor function.","evidence":"ITC binding assays, X-ray crystallography at 1.1 and 1.7 Å resolution, mutagenesis, Co-IP in HEK293 cells","pmids":["24379409"],"confidence":"High","gaps":["Whether bivalent binding mode applies to other NEDD4-family members (WWP2, Itch) was not tested","No structural information for the full-length ARRDC3 protein"]},{"year":2014,"claim":"Crystal structures of the ARRDC3 N-terminal arrestin fold revealed a large electropositive surface essential for β2AR binding, demonstrating that α-arrestins recognize receptors through a mechanism analogous to classical β-arrestins.","evidence":"X-ray crystallography at 1.73 and 2.8 Å, mutagenesis of basic-patch residues, receptor binding assays","pmids":["25220262"],"confidence":"High","gaps":["No co-crystal with β2AR or other receptor was obtained","Whether the same surface mediates all receptor interactions was not addressed"]},{"year":2014,"claim":"Epigenetic silencing of ARRDC3 by SIRT2 in basal-like breast cancer provided a mechanism for how ARRDC3 tumor-suppressive function is lost, linking histone deacetylation at the ARRDC3 promoter to its transcriptional repression.","evidence":"ChIP showing SIRT2 occupancy at ARRDC3 promoter, class III HDAC inhibitor rescue of expression","pmids":["24457910"],"confidence":"Medium","gaps":["Whether SIRT2-mediated silencing occurs broadly across cancer types is unknown","No in vivo validation of SIRT2 inhibition restoring ARRDC3-dependent tumor suppression"]},{"year":2015,"claim":"Discovery that ARRDC3 bridges ALIX to the NEDD4-family ligase WWP2 for GPCR sorting established a new ESCRT-dependent trafficking route: ARRDC3 is required for WWP2-mediated ALIX ubiquitination and subsequent PAR1 lysosomal degradation via CHMP4B/ESCRT-III.","evidence":"siRNA depletion, Co-IP, colocalization at late endosomes, systematic screen of 9 NEDD4-family E3 ligases","pmids":["26490116"],"confidence":"High","gaps":["Direct physical interaction between ARRDC3 and PAR1 was not demonstrated in this study","Whether ARRDC3 bridges ALIX-WWP2 for other GPCRs was untested"]},{"year":2016,"claim":"Localization of ARRDC3 to EEA1-positive early endosomes and its role in delaying β2AR recycling into SNX27-occupied tubules revealed a new function: controlling endosomal residence time to tune receptor signaling output.","evidence":"Confocal imaging, Co-IP, live-cell imaging of endosomal tubules, cAMP signaling assays with ARRDC3 overexpression/knockdown","pmids":["27226565"],"confidence":"High","gaps":["Molecular mechanism by which ARRDC3 excludes β2AR from SNX27 tubules was not defined","Whether this recycling delay generalizes to other GPCRs was not tested"]},{"year":2017,"claim":"Adipocyte-specific Arrdc3 deletion revealed a role in energy metabolism by increasing UCP1 expression in white adipose tissue through a mechanism independent of canonical β-adrenergic signaling, expanding ARRDC3's physiological roles beyond cancer.","evidence":"Conditional adipocyte-specific knockout mice, β-adrenergic stimulation assays, metabolic phenotyping","pmids":["28291835"],"confidence":"Medium","gaps":["The pathway by which ARRDC3 suppresses UCP1 in the absence of β-adrenergic signaling was not identified","No direct target mediating this effect was established"]},{"year":2018,"claim":"Identification of YAP and TAZ as ARRDC3 targets connected ARRDC3 to Hippo pathway regulation: ARRDC3 promotes Itch-mediated YAP ubiquitination and degradation (conserved from Drosophila to mammals) and independently sequesters TAZ via PPXY–WW domain interactions, suppressing cancer cell invasion and metastasis.","evidence":"TAP-MS interactome, Co-IP with PPXY mutagenesis, ubiquitination assays, Drosophila genetics, in vivo lung metastasis model","pmids":["29416926","29364502","33722977"],"confidence":"High","gaps":["Whether ARRDC3-mediated YAP/TAZ regulation occurs in all tissue contexts is unknown","Relative contributions of YAP degradation vs. TAZ sequestration to tumor suppression are not quantified"]},{"year":2018,"claim":"Re-expression of ARRDC3 in invasive breast carcinoma cells restored ALIX-dependent PAR1 lysosomal degradation and attenuated JNK signaling, providing direct functional evidence for ARRDC3 as a tumor suppressor through receptor trafficking.","evidence":"Inducible lentiviral re-expression, flow cytometry trafficking assays, JNK inhibitor phenocopy, invasion assays","pmids":["29348172"],"confidence":"High","gaps":["Whether ARRDC3 loss is sufficient to initiate tumorigenesis or only promotes invasion was not distinguished"]},{"year":2020,"claim":"ARRDC3 was identified as a direct substrate and trafficking adaptor for the insulin receptor: IR phosphorylates ARRDC3 at Y382, and liver-specific Arrdc3 knockout increases surface IR abundance, enhancing hepatic insulin sensitivity and gluconeogenic gene regulation.","evidence":"Liver-specific knockout mice, euglycemic-hyperinsulinemic clamps, Co-IP, plasma membrane fractionation, Y382 mutagenesis","pmids":["32156724"],"confidence":"High","gaps":["Which E3 ligase mediates IR ubiquitination downstream of ARRDC3 was not identified","Whether Y382 phosphorylation feeds back to regulate ARRDC3 stability was not tested"]},{"year":2023,"claim":"Ubiquitination of ARRDC3 itself, mediated through its PPXY motifs, was shown to regulate its own stability, subcellular localization, and WWP2 interaction, establishing a self-regulatory feedback loop essential for GPCR trafficking function.","evidence":"PPXY mutagenesis, ubiquitination assays, subcellular fractionation/imaging, GPCR trafficking assays","pmids":["37223976"],"confidence":"High","gaps":["Which specific ubiquitin chain types on ARRDC3 mediate degradation vs. localization was not resolved","Deubiquitinase(s) counteracting ARRDC3 ubiquitination are unknown"]},{"year":2024,"claim":"Extension of ARRDC3's receptor-targeting repertoire to AXL showed that ARRDC3 promotes AXL ubiquitination and degradation, negatively regulating Akt/ERK signaling and modulating sunitinib sensitivity in renal cell carcinoma.","evidence":"Co-IP with wild-type and mutant proteins, CRISPR-Cas9 ARRDC3 knockout, ubiquitination assays, drug sensitivity experiments","pmids":["38389126"],"confidence":"Medium","gaps":["The E3 ligase mediating AXL ubiquitination via ARRDC3 was not identified","Whether ARRDC3-AXL interaction is direct or bridged was not fully resolved"]},{"year":2025,"claim":"A phospho-regulatory switch at Y394 was discovered that determines ARRDC3 partner selection: phosphorylation at Y394 promotes c-Src SH2 binding and disrupts WWP2 interaction, diverting ARRDC3 from cargo trafficking to kinase regulation.","evidence":"Y394 mutagenesis, Co-IP, SH2 domain binding assays, PAR1 trafficking assays, c-Src activity assays","pmids":["40409556"],"confidence":"High","gaps":["The kinase(s) that phosphorylate Y394 in vivo are unknown","Physiological contexts in which the Y394 switch is activated have not been defined"]},{"year":2025,"claim":"ARRDC3-mediated YAP degradation was linked to antiviral immunity: by promoting lysosomal YAP turnover, ARRDC3 derepresses the interferon pathway and inhibits enterovirus and paramyxovirus replication.","evidence":"Overexpression/knockdown of ARRDC3 and YAP, lysosomal inhibitors, interferon reporter assays, multi-virus replication assays","pmids":["40701343"],"confidence":"Medium","gaps":["Whether ARRDC3 antiviral function operates in vivo is untested","The mechanism by which YAP suppresses interferon signaling independently of transcription is poorly defined"]},{"year":null,"claim":"Key unresolved questions include the identity of kinase(s) phosphorylating Y394, how ARRDC3's dual early- and late-endosome localization is coordinated, whether ARRDC3 has additional non-receptor substrates, and the structural basis for full-length ARRDC3 in complex with any receptor or E3 ligase.","evidence":"","pmids":[],"confidence":"Low","gaps":["No full-length ARRDC3 structure or receptor co-complex exists","Deubiquitinases regulating ARRDC3 turnover are unidentified","Tissue-specific functions beyond liver, adipose, and breast remain largely unexplored"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,3,6,8,9,12]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,5,8,12]}],"localization":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[3,4,10]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[4,10]}],"pathway":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[3,4,10]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,5,8,12]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[1,3,6,10,11]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,3,4,5,8]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[0,5,6,7,9,11]}],"complexes":[],"partners":["NEDD4","WWP2","ITCH","ALIX","YAP1","TAZ","INSR","CSRC"],"other_free_text":[]},"mechanistic_narrative":"ARRDC3 is an α-arrestin adaptor protein that functions as a trafficking hub, recruiting NEDD4-family E3 ubiquitin ligases (NEDD4, WWP2, Itch) via bivalent engagement of its C-terminal PPXY motifs to promote ubiquitination and lysosomal degradation of diverse transmembrane receptors and signaling effectors including integrin β4, β2-adrenergic receptor, PAR1 (via ALIX/ESCRT-III), the insulin receptor, AXL, and the Hippo pathway co-activators YAP and TAZ [PMID:20603614, PMID:24379409, PMID:26490116, PMID:27226565, PMID:32156724, PMID:29416926, PMID:33722977, PMID:38389126]. Its N-terminal arrestin-fold domain contains an electropositive surface that mediates ligand-independent receptor binding, while its scaffolding output is toggled by phosphorylation: insulin receptor-mediated phosphorylation at Y382 promotes IR internalization, and phosphorylation at Y394 switches ARRDC3 from WWP2 binding to c-Src SH2 domain engagement, thereby redirecting cargo trafficking versus kinase signaling [PMID:25220262, PMID:32156724, PMID:40409556]. ARRDC3 localizes primarily to early endosomes where it delays β2AR recycling into SNX27-positive tubules, prolongs endosomal signaling, and through its PPXY-mediated sequestration of TAZ and Itch-dependent degradation of YAP functions as a tumor suppressor in breast and renal cell carcinomas by attenuating Hippo, JNK, and Akt/ERK signaling [PMID:27226565, PMID:29348172, PMID:33722977, PMID:29416926]."},"prefetch_data":{"uniprot":{"accession":"Q96B67","full_name":"Arrestin domain-containing protein 3","aliases":["TBP-2-like inducible membrane protein","TLIMP"],"length_aa":414,"mass_kda":46.4,"function":"Adapter protein that plays a role in regulating cell-surface expression of adrenergic receptors and probably also other G protein-coupled receptors (PubMed:20559325, PubMed:21982743, PubMed:23208550). Plays a role in NEDD4-mediated ubiquitination and endocytosis af activated ADRB2 and subsequent ADRB2 degradation (PubMed:20559325, PubMed:23208550). May recruit NEDD4 to ADRB2 (PubMed:20559325). Alternatively, may function as adapter protein that does not play a major role in recruiting NEDD4 to ADRB2, but rather plays a role in a targeting ADRB2 to endosomes (PubMed:23208550)","subcellular_location":"Cytoplasm; Cell membrane; Lysosome; Endosome; Early endosome","url":"https://www.uniprot.org/uniprotkb/Q96B67/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ARRDC3","classification":"Not Classified","n_dependent_lines":7,"n_total_lines":1208,"dependency_fraction":0.005794701986754967},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ARRDC3","total_profiled":1310},"omim":[{"mim_id":"621542","title":"ARRESTIN DOMAIN-CONTAINING PROTEIN 2; ARRDC2","url":"https://www.omim.org/entry/621542"},{"mim_id":"619788","title":"ARRESTIN DOMAIN-CONTAINING PROTEIN 4; ARRDC4","url":"https://www.omim.org/entry/619788"},{"mim_id":"618190","title":"LUNG CANCER-ASSOCIATED TRANSCRIPT 1, NONCODING; LUCAT1","url":"https://www.omim.org/entry/618190"},{"mim_id":"612464","title":"ARRESTIN DOMAIN-CONTAINING PROTEIN 3; ARRDC3","url":"https://www.omim.org/entry/612464"}],"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/ARRDC3"},"hgnc":{"alias_symbol":["KIAA1376","TLIMP"],"prev_symbol":[]},"alphafold":{"accession":"Q96B67","domains":[{"cath_id":"2.60.40.640","chopping":"5-157","consensus_level":"high","plddt":90.3567,"start":5,"end":157},{"cath_id":"2.60.40.640","chopping":"166-308","consensus_level":"high","plddt":94.4318,"start":166,"end":308}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96B67","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96B67-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96B67-F1-predicted_aligned_error_v6.png","plddt_mean":82.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ARRDC3","jax_strain_url":"https://www.jax.org/strain/search?query=ARRDC3"},"sequence":{"accession":"Q96B67","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96B67.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96B67/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96B67"}},"corpus_meta":[{"pmid":"20603614","id":"PMC_20603614","title":"ARRDC3 suppresses breast cancer progression by negatively regulating integrin beta4.","date":"2010","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/20603614","citation_count":98,"is_preprint":false},{"pmid":"26490116","id":"PMC_26490116","title":"The α-arrestin ARRDC3 mediates ALIX ubiquitination and G protein-coupled receptor lysosomal sorting.","date":"2015","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/26490116","citation_count":71,"is_preprint":false},{"pmid":"24379409","id":"PMC_24379409","title":"Structural and biochemical basis for ubiquitin ligase recruitment by arrestin-related domain-containing protein-3 (ARRDC3).","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24379409","citation_count":69,"is_preprint":false},{"pmid":"27226565","id":"PMC_27226565","title":"The α-Arrestin ARRDC3 Regulates the Endosomal Residence Time and Intracellular Signaling of the β2-Adrenergic Receptor.","date":"2016","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/27226565","citation_count":65,"is_preprint":false},{"pmid":"27109471","id":"PMC_27109471","title":"Androgen receptor regulated microRNA miR-182-5p promotes prostate cancer progression by targeting the ARRDC3/ITGB4 pathway.","date":"2016","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/27109471","citation_count":54,"is_preprint":false},{"pmid":"24457910","id":"PMC_24457910","title":"Epigenetic silencing of ARRDC3 expression in basal-like breast cancer cells.","date":"2014","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/24457910","citation_count":51,"is_preprint":false},{"pmid":"29416926","id":"PMC_29416926","title":"ARRDC1 and ARRDC3 act as tumor suppressors in renal cell carcinoma by facilitating YAP1 degradation.","date":"2018","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/29416926","citation_count":40,"is_preprint":false},{"pmid":"32156724","id":"PMC_32156724","title":"Arrestin domain-containing 3 (Arrdc3) modulates insulin action and glucose metabolism in liver.","date":"2020","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/32156724","citation_count":39,"is_preprint":false},{"pmid":"29348172","id":"PMC_29348172","title":"The α-arrestin ARRDC3 suppresses breast carcinoma invasion by regulating G protein-coupled receptor lysosomal sorting and signaling.","date":"2018","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29348172","citation_count":39,"is_preprint":false},{"pmid":"30412241","id":"PMC_30412241","title":"Genome-wide association study of cervical cancer suggests a role for ARRDC3 gene in human papillomavirus infection.","date":"2019","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30412241","citation_count":36,"is_preprint":false},{"pmid":"29364502","id":"PMC_29364502","title":"ARRDC3 suppresses colorectal cancer progression through destabilizing the oncoprotein YAP.","date":"2018","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/29364502","citation_count":30,"is_preprint":false},{"pmid":"34465145","id":"PMC_34465145","title":"The α-Arrestin ARRDC3 Is an Emerging Multifunctional Adaptor Protein in Cancer.","date":"2022","source":"Antioxidants & redox signaling","url":"https://pubmed.ncbi.nlm.nih.gov/34465145","citation_count":26,"is_preprint":false},{"pmid":"28782483","id":"PMC_28782483","title":"ARRDC3 Inhibits the Progression of Human Prostate Cancer Through ARRDC3-ITGβ4 Pathway.","date":"2017","source":"Current molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/28782483","citation_count":26,"is_preprint":false},{"pmid":"33722977","id":"PMC_33722977","title":"α-Arrestin ARRDC3 tumor 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preeclampsia.","date":"2019","source":"Placenta","url":"https://pubmed.ncbi.nlm.nih.gov/31665660","citation_count":15,"is_preprint":false},{"pmid":"36154540","id":"PMC_36154540","title":"ARRDC3 inhibits liver fibrosis and epithelial-to-mesenchymal transition via the ITGB4/PI3K/Akt signaling pathway.","date":"2022","source":"Immunopharmacology and immunotoxicology","url":"https://pubmed.ncbi.nlm.nih.gov/36154540","citation_count":14,"is_preprint":false},{"pmid":"35218583","id":"PMC_35218583","title":"An association of CEP78, MEF2C, VPS13A and ARRDC3 genes with survivability to heat stress in an F2 chicken population.","date":"2022","source":"Journal of animal breeding and genetics = Zeitschrift fur Tierzuchtung und Zuchtungsbiologie","url":"https://pubmed.ncbi.nlm.nih.gov/35218583","citation_count":13,"is_preprint":false},{"pmid":"37062135","id":"PMC_37062135","title":"Fuzheng Kang-Ai inhibits NSCLC cell proliferation via regulating hsa_circ_0048091/hsa-miR-378g/ARRDC3 pathway.","date":"2023","source":"Phytomedicine : international journal of phytotherapy and phytopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/37062135","citation_count":11,"is_preprint":false},{"pmid":"38680232","id":"PMC_38680232","title":"Association of ARRDC3 and NFIA variants with bovine congestive heart failure in feedlot cattle.","date":"2024","source":"F1000Research","url":"https://pubmed.ncbi.nlm.nih.gov/38680232","citation_count":9,"is_preprint":false},{"pmid":"28291835","id":"PMC_28291835","title":"Adipocyte arrestin domain-containing 3 protein (Arrdc3) regulates uncoupling protein 1 (Ucp1) expression in white adipose independently of canonical changes in β-adrenergic receptor signaling.","date":"2017","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/28291835","citation_count":9,"is_preprint":false},{"pmid":"37223976","id":"PMC_37223976","title":"Divergent regulation of α-arrestin ARRDC3 function by ubiquitination.","date":"2023","source":"Molecular biology 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Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/40701343","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":20812,"output_tokens":4123,"usd":0.062141},"stage2":{"model":"claude-opus-4-6","input_tokens":7612,"output_tokens":3872,"usd":0.20229},"total_usd":0.264431,"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\": 2010,\n      \"finding\": \"ARRDC3 directly binds to a phosphorylated form of integrin beta-4 (ITGβ4), leading to its internalization, ubiquitination, and degradation, thereby suppressing breast cancer cell proliferation, migration, and invasion.\",\n      \"method\": \"Co-immunoprecipitation, overexpression/knockdown with functional phenotypic readouts (proliferation, migration, invasion, soft agar, xenograft)\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP plus multiple orthogonal functional assays, foundational study with 98 citations\",\n      \"pmids\": [\"20603614\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ARRDC3 recruits the NEDD4-family E3 ubiquitin ligase NEDD4 via two C-terminal PPXY motifs; the highest-affinity interaction is between ARRDC3 PPXY1 and NEDD4 WW3 domain (Kd ~3 μM), while avid binding of full-length proteins is driven by bivalent engagement of WW2-WW3 or WW3-WW4 combinations (Kd ~300 nM); crystal structures of uncomplexed and PPXY1-bound WW3 at 1.1 and 1.7 Å revealed conformational changes and the hydrogen-bonding network, with Val-352' in a 310 helix being critical for high-affinity binding.\",\n      \"method\": \"ITC binding assays, X-ray crystallography (1.1 and 1.7 Å), mutagenesis, Co-IP in HEK293 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structures with mutagenesis and in vitro binding assays in a single rigorous study\",\n      \"pmids\": [\"24379409\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Crystal structures of the N-terminal lobe of human ARRDC3 at 1.73 and 2.8 Å revealed a large electropositive region; residues within this basic patch were shown to be important for binding to β2-adrenergic receptor (β2AR), paralleling receptor recognition by β-arrestins.\",\n      \"method\": \"X-ray crystallography, mutagenesis, binding assays\",\n      \"journal\": \"Protein science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structures with mutagenesis validation of receptor-binding residues\",\n      \"pmids\": [\"25220262\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"ARRDC3 colocalizes with ALIX at late endosomes and is required for ALIX ubiquitination (mediated by NEDD4-family ligase WWP2, which interacts with ARRDC3 but not ALIX), ALIX interaction with activated PAR1 and CHMP4B ESCRT-III, and subsequent lysosomal degradation of protease-activated receptor-1 (PAR1).\",\n      \"method\": \"siRNA depletion, Co-IP, immunofluorescence colocalization, E3 ligase screen (9 NEDD4-family members)\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP, systematic ligase screen, and colocalization with functional consequence, replicated in subsequent studies\",\n      \"pmids\": [\"26490116\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"ARRDC3 localizes primarily to EEA1-positive early endosomes, directly interacts with β2AR in a ligand-independent manner, negatively regulates β2AR entry into SNX27-occupied endosomal tubules, thereby delaying receptor recycling and increasing β2AR-dependent endosomal signaling.\",\n      \"method\": \"Confocal immunofluorescence, Co-IP, ARRDC3 overexpression/knockdown, live-cell imaging of endosomal tubules, cAMP signaling assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct localization experiments tied to functional consequences with multiple orthogonal methods\",\n      \"pmids\": [\"27226565\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ARRDC3 acts as a tumor suppressor in breast carcinoma by restoring lysosomal degradation of PAR1 through the ALIX-dependent pathway, attenuating persistent PAR1-stimulated JNK signaling, and thereby reducing breast carcinoma invasion.\",\n      \"method\": \"Lentiviral doxycycline-inducible re-expression, flow cytometry/trafficking assays, JNK inhibition, invasion assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean re-expression system with defined trafficking and signaling readouts, multiple orthogonal methods\",\n      \"pmids\": [\"29348172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ARRDC3 interacts with YAP1 via its PPXY motifs (binding to YAP1 WW domains) and facilitates Itch E3 ubiquitin ligase-mediated ubiquitination and degradation of YAP1, suppressing Hippo pathway activation in clear cell renal cell carcinoma.\",\n      \"method\": \"Tandem affinity purification/mass spectrometry, Co-IP, shRNA knockdown, mutagenesis of PPXY motifs, ubiquitination assays\",\n      \"journal\": \"American journal of cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — MS-based interactome discovery confirmed by Co-IP with domain mapping and functional ubiquitination assays\",\n      \"pmids\": [\"29416926\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ARRDC3 binds and decreases expression of the oncoprotein YAP, promoting its lysosome-mediated degradation, thereby suppressing colorectal cancer progression; this regulation of the Hippo pathway by ARRDC3 is conserved from Drosophila to mammals.\",\n      \"method\": \"Co-IP, overexpression/knockdown, lysosome inhibitor assays, Drosophila genetic analysis\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP with functional KD/OE and pathway validation, but single lab study\",\n      \"pmids\": [\"29364502\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ARRDC3 directly interacts with the insulin receptor (IR) and is phosphorylated by IR on a conserved tyrosine residue Y382 in its carboxyl-terminal domain; this interaction promotes IR internalization, and liver-specific knockout of Arrdc3 increases IR at the plasma membrane, enhancing hepatic insulin sensitivity with increased FOXO1 phosphorylation, reduced PEPCK, and increased glucokinase expression.\",\n      \"method\": \"Liver-specific knockout mice, euglycemic-hyperinsulinemic clamps, Co-IP, plasma membrane fractionation, phospho-Western blotting, mutagenesis (Y382)\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined metabolic phenotype, Co-IP, mutagenesis of phosphorylation site, multiple orthogonal methods\",\n      \"pmids\": [\"32156724\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ARRDC3 suppresses PAR1-induced Hippo signaling by sequestering the transcriptional co-activator TAZ, independently of ARRDC3-regulated PAR1 trafficking; the ARRDC3 C-terminal PPXY motifs and TAZ WW domain are crucial for this interaction, which suppresses TNBC migration and lung metastasis in vivo.\",\n      \"method\": \"Co-IP, PPXY motif mutagenesis, siRNA depletion, migration/invasion assays, in vivo lung metastasis model\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP with domain mapping, in vivo validation, multiple orthogonal functional assays\",\n      \"pmids\": [\"33722977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Ubiquitination of ARRDC3, mediated primarily through its two C-terminal PPXY motifs, regulates ARRDC3 protein degradation, dictates its subcellular localization, controls its interaction with WWP2, and is essential for ARRDC3-dependent GPCR trafficking and signaling.\",\n      \"method\": \"Mutagenesis of PPXY motifs, ubiquitination assays, Co-IP, subcellular fractionation/imaging, GPCR trafficking assays\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — mutagenesis combined with multiple orthogonal functional and localization assays\",\n      \"pmids\": [\"37223976\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ARRDC3 interacts with receptor tyrosine kinase AXL and promotes its ubiquitination and degradation, negatively regulating downstream Akt and ERK phosphorylation; ARRDC3 deficiency decreases sunitinib sensitivity of ccRCC cells in an AXL stability-dependent manner.\",\n      \"method\": \"Co-IP with wildtype and mutant proteins, CRISPR-Cas9 ARRDC3 knockout, ubiquitination assays, pharmacological experiments, immunohistochemistry\",\n      \"journal\": \"Cell cycle\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP with CRISPR KO and functional drug sensitivity assays, single lab study\",\n      \"pmids\": [\"38389126\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ARRDC3 contains a novel phosphorylation site at tyrosine Y394 embedded in the C-terminal PPxY motif that functions as a phospho-regulatory switch: Y394 phosphorylation promotes interaction with c-Src via its SH2 domain and enables regulation of c-Src activity, whereas the non-phosphorylated form binds WWP2; Y394 phosphorylation disrupts WWP2 interaction and perturbs ARRDC3-dependent lysosomal trafficking of PAR1.\",\n      \"method\": \"Mutagenesis (Y394), Co-IP, SH2 domain binding assays, GPCR trafficking assays, c-Src activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — mutagenesis of phosphorylation site with multiple orthogonal functional readouts showing divergent binding partner selection\",\n      \"pmids\": [\"40409556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"SIRT2, a class III HDAC, epigenetically silences ARRDC3 expression in basal-like breast cancer cells by binding to the ARRDC3 promoter and reducing histone acetylation at that locus; inhibitors of class III HDACs restore ARRDC3 expression.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP), HDAC inhibitor treatment, qRT-PCR, Western blotting\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP establishes SIRT2 binding at ARRDC3 promoter with functional inhibitor rescue, single lab\",\n      \"pmids\": [\"24457910\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ARRDC3 promotes lysosomal degradation of YAP, and this mechanism inhibits enterovirus (EV-D68, EV-A71) replication; YAP facilitates enterovirus replication by suppressing the interferon pathway independently of its transcriptional activity, and the ARRDC3-YAP axis also exerts broad-spectrum antiviral effects against HPIV3 and VSV.\",\n      \"method\": \"Overexpression/knockdown of ARRDC3 and YAP, lysosomal pathway inhibition, interferon pathway reporter assays, viral replication assays\",\n      \"journal\": \"Virologica Sinica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional KD/OE with defined pathway (lysosomal YAP degradation) and multiple virus models, single lab\",\n      \"pmids\": [\"40701343\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Adipocyte-specific deletion of Arrdc3 increases UCP1 expression in subcutaneous and parametrial white adipose tissue, but this effect is independent of canonical β-adrenergic receptor signaling, as Arrdc3-null adipocytes show decreased UCP1 levels in response to β-adrenergic agonist.\",\n      \"method\": \"Conditional adipocyte-specific Arrdc3 knockout mice, in vitro β-adrenergic stimulation assays, Western blotting for UCP1 and signaling proteins, metabolic phenotyping\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined cellular phenotype and mechanistic exclusion of canonical pathway, single lab\",\n      \"pmids\": [\"28291835\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ARRDC3 upregulation in ischemic neurons promotes Drp1-dependent mitochondrial fragmentation and neuronal ferroptosis; this pathway is suppressed by exosomal CRYAB, which reduces ARRDC3 expression.\",\n      \"method\": \"Transcriptomic analysis, overexpression/knockdown of ARRDC3 and Drp1, ferroptosis assays, MCAO/R mouse model\",\n      \"journal\": \"Advanced healthcare materials\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — functional KD/OE with phenotypic readout but limited direct mechanistic validation of ARRDC3-Drp1 interaction\",\n      \"pmids\": [\"41555725\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ARRDC3 is a multifunctional α-arrestin adaptor protein that recruits NEDD4-family E3 ubiquitin ligases (NEDD4, WWP2, Itch) via its C-terminal PPXY motifs to promote ubiquitination and lysosomal or proteasomal degradation of target proteins including ITGβ4, β2AR, PAR1 (via ALIX), YAP/TAZ, AXL, and the insulin receptor; its scaffolding functions are regulated by phosphorylation (Y382 by insulin receptor, Y394 as a switch between c-Src SH2 vs. WWP2 binding) and by its own ubiquitination status, while its subcellular localization to early endosomes positions it to control GPCR endosomal residence time, recycling, and downstream signaling.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ARRDC3 is an α-arrestin adaptor protein that functions as a trafficking hub, recruiting NEDD4-family E3 ubiquitin ligases (NEDD4, WWP2, Itch) via bivalent engagement of its C-terminal PPXY motifs to promote ubiquitination and lysosomal degradation of diverse transmembrane receptors and signaling effectors including integrin β4, β2-adrenergic receptor, PAR1 (via ALIX/ESCRT-III), the insulin receptor, AXL, and the Hippo pathway co-activators YAP and TAZ [PMID:20603614, PMID:24379409, PMID:26490116, PMID:27226565, PMID:32156724, PMID:29416926, PMID:33722977, PMID:38389126]. Its N-terminal arrestin-fold domain contains an electropositive surface that mediates ligand-independent receptor binding, while its scaffolding output is toggled by phosphorylation: insulin receptor-mediated phosphorylation at Y382 promotes IR internalization, and phosphorylation at Y394 switches ARRDC3 from WWP2 binding to c-Src SH2 domain engagement, thereby redirecting cargo trafficking versus kinase signaling [PMID:25220262, PMID:32156724, PMID:40409556]. ARRDC3 localizes primarily to early endosomes where it delays β2AR recycling into SNX27-positive tubules, prolongs endosomal signaling, and through its PPXY-mediated sequestration of TAZ and Itch-dependent degradation of YAP functions as a tumor suppressor in breast and renal cell carcinomas by attenuating Hippo, JNK, and Akt/ERK signaling [PMID:27226565, PMID:29348172, PMID:33722977, PMID:29416926].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"The initial identification of ARRDC3 as a functional adaptor established that it directly binds phosphorylated integrin β4, promoting its internalization and degradation, thereby revealing ARRDC3 as a tumor-suppressive regulator of receptor turnover.\",\n      \"evidence\": \"Co-immunoprecipitation, overexpression/knockdown with proliferation, migration, invasion, and xenograft assays in breast cancer cells\",\n      \"pmids\": [\"20603614\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of ITGβ4 ubiquitination (which E3 ligase) was not identified\", \"Whether ARRDC3 PPXY motifs mediate ligase recruitment in this context was unknown\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Structural and biophysical dissection of the ARRDC3–NEDD4 interaction defined the molecular basis for E3 ligase recruitment: bivalent engagement of two PPXY motifs with NEDD4 WW domains achieves ~300 nM affinity, establishing the mechanistic framework for ARRDC3's adaptor function.\",\n      \"evidence\": \"ITC binding assays, X-ray crystallography at 1.1 and 1.7 Å resolution, mutagenesis, Co-IP in HEK293 cells\",\n      \"pmids\": [\"24379409\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether bivalent binding mode applies to other NEDD4-family members (WWP2, Itch) was not tested\", \"No structural information for the full-length ARRDC3 protein\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Crystal structures of the ARRDC3 N-terminal arrestin fold revealed a large electropositive surface essential for β2AR binding, demonstrating that α-arrestins recognize receptors through a mechanism analogous to classical β-arrestins.\",\n      \"evidence\": \"X-ray crystallography at 1.73 and 2.8 Å, mutagenesis of basic-patch residues, receptor binding assays\",\n      \"pmids\": [\"25220262\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No co-crystal with β2AR or other receptor was obtained\", \"Whether the same surface mediates all receptor interactions was not addressed\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Epigenetic silencing of ARRDC3 by SIRT2 in basal-like breast cancer provided a mechanism for how ARRDC3 tumor-suppressive function is lost, linking histone deacetylation at the ARRDC3 promoter to its transcriptional repression.\",\n      \"evidence\": \"ChIP showing SIRT2 occupancy at ARRDC3 promoter, class III HDAC inhibitor rescue of expression\",\n      \"pmids\": [\"24457910\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether SIRT2-mediated silencing occurs broadly across cancer types is unknown\", \"No in vivo validation of SIRT2 inhibition restoring ARRDC3-dependent tumor suppression\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Discovery that ARRDC3 bridges ALIX to the NEDD4-family ligase WWP2 for GPCR sorting established a new ESCRT-dependent trafficking route: ARRDC3 is required for WWP2-mediated ALIX ubiquitination and subsequent PAR1 lysosomal degradation via CHMP4B/ESCRT-III.\",\n      \"evidence\": \"siRNA depletion, Co-IP, colocalization at late endosomes, systematic screen of 9 NEDD4-family E3 ligases\",\n      \"pmids\": [\"26490116\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct physical interaction between ARRDC3 and PAR1 was not demonstrated in this study\", \"Whether ARRDC3 bridges ALIX-WWP2 for other GPCRs was untested\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Localization of ARRDC3 to EEA1-positive early endosomes and its role in delaying β2AR recycling into SNX27-occupied tubules revealed a new function: controlling endosomal residence time to tune receptor signaling output.\",\n      \"evidence\": \"Confocal imaging, Co-IP, live-cell imaging of endosomal tubules, cAMP signaling assays with ARRDC3 overexpression/knockdown\",\n      \"pmids\": [\"27226565\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism by which ARRDC3 excludes β2AR from SNX27 tubules was not defined\", \"Whether this recycling delay generalizes to other GPCRs was not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Adipocyte-specific Arrdc3 deletion revealed a role in energy metabolism by increasing UCP1 expression in white adipose tissue through a mechanism independent of canonical β-adrenergic signaling, expanding ARRDC3's physiological roles beyond cancer.\",\n      \"evidence\": \"Conditional adipocyte-specific knockout mice, β-adrenergic stimulation assays, metabolic phenotyping\",\n      \"pmids\": [\"28291835\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The pathway by which ARRDC3 suppresses UCP1 in the absence of β-adrenergic signaling was not identified\", \"No direct target mediating this effect was established\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identification of YAP and TAZ as ARRDC3 targets connected ARRDC3 to Hippo pathway regulation: ARRDC3 promotes Itch-mediated YAP ubiquitination and degradation (conserved from Drosophila to mammals) and independently sequesters TAZ via PPXY–WW domain interactions, suppressing cancer cell invasion and metastasis.\",\n      \"evidence\": \"TAP-MS interactome, Co-IP with PPXY mutagenesis, ubiquitination assays, Drosophila genetics, in vivo lung metastasis model\",\n      \"pmids\": [\"29416926\", \"29364502\", \"33722977\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ARRDC3-mediated YAP/TAZ regulation occurs in all tissue contexts is unknown\", \"Relative contributions of YAP degradation vs. TAZ sequestration to tumor suppression are not quantified\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Re-expression of ARRDC3 in invasive breast carcinoma cells restored ALIX-dependent PAR1 lysosomal degradation and attenuated JNK signaling, providing direct functional evidence for ARRDC3 as a tumor suppressor through receptor trafficking.\",\n      \"evidence\": \"Inducible lentiviral re-expression, flow cytometry trafficking assays, JNK inhibitor phenocopy, invasion assays\",\n      \"pmids\": [\"29348172\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ARRDC3 loss is sufficient to initiate tumorigenesis or only promotes invasion was not distinguished\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"ARRDC3 was identified as a direct substrate and trafficking adaptor for the insulin receptor: IR phosphorylates ARRDC3 at Y382, and liver-specific Arrdc3 knockout increases surface IR abundance, enhancing hepatic insulin sensitivity and gluconeogenic gene regulation.\",\n      \"evidence\": \"Liver-specific knockout mice, euglycemic-hyperinsulinemic clamps, Co-IP, plasma membrane fractionation, Y382 mutagenesis\",\n      \"pmids\": [\"32156724\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which E3 ligase mediates IR ubiquitination downstream of ARRDC3 was not identified\", \"Whether Y382 phosphorylation feeds back to regulate ARRDC3 stability was not tested\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Ubiquitination of ARRDC3 itself, mediated through its PPXY motifs, was shown to regulate its own stability, subcellular localization, and WWP2 interaction, establishing a self-regulatory feedback loop essential for GPCR trafficking function.\",\n      \"evidence\": \"PPXY mutagenesis, ubiquitination assays, subcellular fractionation/imaging, GPCR trafficking assays\",\n      \"pmids\": [\"37223976\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which specific ubiquitin chain types on ARRDC3 mediate degradation vs. localization was not resolved\", \"Deubiquitinase(s) counteracting ARRDC3 ubiquitination are unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Extension of ARRDC3's receptor-targeting repertoire to AXL showed that ARRDC3 promotes AXL ubiquitination and degradation, negatively regulating Akt/ERK signaling and modulating sunitinib sensitivity in renal cell carcinoma.\",\n      \"evidence\": \"Co-IP with wild-type and mutant proteins, CRISPR-Cas9 ARRDC3 knockout, ubiquitination assays, drug sensitivity experiments\",\n      \"pmids\": [\"38389126\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The E3 ligase mediating AXL ubiquitination via ARRDC3 was not identified\", \"Whether ARRDC3-AXL interaction is direct or bridged was not fully resolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"A phospho-regulatory switch at Y394 was discovered that determines ARRDC3 partner selection: phosphorylation at Y394 promotes c-Src SH2 binding and disrupts WWP2 interaction, diverting ARRDC3 from cargo trafficking to kinase regulation.\",\n      \"evidence\": \"Y394 mutagenesis, Co-IP, SH2 domain binding assays, PAR1 trafficking assays, c-Src activity assays\",\n      \"pmids\": [\"40409556\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The kinase(s) that phosphorylate Y394 in vivo are unknown\", \"Physiological contexts in which the Y394 switch is activated have not been defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"ARRDC3-mediated YAP degradation was linked to antiviral immunity: by promoting lysosomal YAP turnover, ARRDC3 derepresses the interferon pathway and inhibits enterovirus and paramyxovirus replication.\",\n      \"evidence\": \"Overexpression/knockdown of ARRDC3 and YAP, lysosomal inhibitors, interferon reporter assays, multi-virus replication assays\",\n      \"pmids\": [\"40701343\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ARRDC3 antiviral function operates in vivo is untested\", \"The mechanism by which YAP suppresses interferon signaling independently of transcription is poorly defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the identity of kinase(s) phosphorylating Y394, how ARRDC3's dual early- and late-endosome localization is coordinated, whether ARRDC3 has additional non-receptor substrates, and the structural basis for full-length ARRDC3 in complex with any receptor or E3 ligase.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No full-length ARRDC3 structure or receptor co-complex exists\", \"Deubiquitinases regulating ARRDC3 turnover are unidentified\", \"Tissue-specific functions beyond liver, adipose, and breast remain largely unexplored\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 3, 6, 8, 9, 12]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 5, 8, 12]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [3, 4, 10]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [4, 10]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [3, 4, 10]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 5, 8, 12]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [1, 3, 6, 10, 11]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 3, 4, 5, 8]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [0, 5, 6, 7, 9, 11]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"NEDD4\", \"WWP2\", \"ITCH\", \"ALIX\", \"YAP1\", \"TAZ\", \"INSR\", \"CSRC\"],\n    \"other_free_text\": []\n  }\n}\n```"}