{"gene":"NRBP1","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2000,"finding":"NRBP1 (NRBP) was identified as a multidomain putative adapter protein containing two LXXLL nuclear receptor binding motifs, a putative SH2 domain-binding domain, a kinase-like domain, a bipartite nuclear localization signal, and PEST sequences. In vitro translation revealed three products of 60, 51, and 43 kDa, suggesting multiple translation initiation sites.","method":"cDNA cloning, in vitro translation, domain analysis","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct biochemical characterization by in vitro translation and domain mapping; single lab but multiple orthogonal methods","pmids":["10843813"],"is_preprint":false},{"year":2002,"finding":"NRBP1 forms a complex with constitutively activated Rac3 (V12Rac3) and exhibits an associated kinase activity. NRBP and activated Rac3 co-localize to endomembranes and at the cell periphery in lamellipodia. Overexpression of NRBP caused redistribution of Golgi-associated marker p58 to more peripheral locations, consistent with impairment of ER-to-Golgi transport, suggesting a role in subcellular trafficking.","method":"Co-IP/pulldown with V12Rac3, kinase activity assay, immunocytochemistry, overexpression in COS-1 cells","journal":"International journal of molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding and kinase assay with co-localization; single lab, multiple methods","pmids":["11956649"],"is_preprint":false},{"year":2006,"finding":"NRBP1 interacts in vivo with Jab1 (the fifth component of the COP9 signalosome complex) and inhibits Jab1-induced phosphorylation of c-Jun and AP-1 activation. Overexpression of NRBP1 in mammalian cells specifically inhibits AP-1 activation by various stimuli.","method":"Co-IP in vivo, AP-1 reporter assay, c-Jun phosphorylation assay, overexpression","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo Co-IP plus functional reporter assay; single lab, two orthogonal methods","pmids":["17052710"],"is_preprint":false},{"year":2020,"finding":"NRBP1 functions as a substrate receptor of a Cullin-RING ubiquitin ligase (CRL) complex targeting BRI2 and BRI3 for degradation. Dimerized NRBP1 assembles into a functional heterodimeric CRL containing both Cul2 and Cul4A through its BC-box and an overlapping cryptic H-box. Formation of the NRBP1 heterodimeric CRL is strongly enhanced by chaperone-like function of TSC22D3 and TSC22D4. NRBP1 knockdown in neuronal cells increases BRI2 and BRI3 abundance and significantly reduces Aβ production.","method":"Co-IP, mass spectrometry, reconstitution of CRL complex, RNAi knockdown, Aβ measurement","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — biochemical reconstitution of CRL complex, MS-based interactome, functional knockdown with defined substrate readout; multiple orthogonal methods in one rigorous study","pmids":["32160551"],"is_preprint":false},{"year":2019,"finding":"NRBP1 induces ubiquitination of SALL4, targeting it for degradation. THG-1 (a NRBP1 binding protein) competes with SALL4 for NRBP1 binding, thereby blocking NRBP1-mediated ubiquitination of SALL4 and stabilizing it to promote stemness gene expression (NANOG, OCT4) and tumorsphere growth in esophageal squamous cell carcinoma cells.","method":"Knockdown and overexpression, ubiquitination assay, competitive binding assay, tumorsphere formation assay","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct ubiquitination assay with competitive binding; single lab, multiple functional assays","pmids":["31864704"],"is_preprint":false},{"year":2021,"finding":"NRBP1 is localized in microglia and neurons (not astrocytes) in mouse medial prefrontal cortex. (R)-ketamine increases NRBP1 expression in primary microglia cultures through ERK activation, and NRBP1 participates in an ERK-NRBP1-CREB-BDNF signaling cascade. Microglial depletion blocked the antidepressant-like effects of (R)-ketamine.","method":"Isobaric quantitative proteomics (iTRAQ), immunofluorescence/immunohistochemistry for localization, primary microglia culture, ERK inhibition, intracerebroventricular HDO injection, microglial depletion (PLX3397, MCLs)","journal":"Molecular psychiatry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — localization by immunofluorescence, pharmacological pathway dissection, functional behavioral readout; single lab, multiple orthogonal approaches","pmids":["34819637"],"is_preprint":false},{"year":2022,"finding":"Drosophila Madm (ortholog of NRBP1) is required presynaptically to maintain synaptic stability and coordinate synaptic growth and function by controlling cap-dependent translation via the TOR effector 4E-BP/Thor. Postsynaptic Madm induces a compensatory transsynaptic signal using the presynaptic homeostatic potentiation (PHP) machinery to offset synaptic release deficits at degenerating neuromuscular synapses, acting via regulation of cap-dependent translation regulators 4E-BP/Thor and S6-kinase.","method":"Genetic loss-of-function (presynaptic and postsynaptic specific knockdown), electrophysiology, imaging of neuromuscular junction, epistasis with TOR pathway components","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis, compartment-specific knockdowns, electrophysiological readout, and mechanistic rescue experiments across multiple orthogonal approaches","pmids":["36450258"],"is_preprint":false},{"year":2023,"finding":"NRBP1 (pseudokinase) acts as a scaffold that binds P-Rex1 (a guanine nucleotide exchange factor for Rac1), Rac1, and Cdc42. NRBP1 overexpression enhances GTP-bound Rac1 and Cdc42 levels in a P-Rex1-dependent manner, while NRBP1 knockdown reduces their activation. NRBP1-mediated promotion of cell migration and invasion is P-Rex1-dependent. Generation of reactive oxygen species via a NRBP1/P-Rex1 pathway is implicated in oncogenic roles.","method":"BioID/MS proximity labeling, Co-IP, GTP-Rac1/Cdc42 pull-down activity assays, siRNA knockdown, P-Rex1-dependent rescue experiments, ROS measurement, xenograft models","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — BioID/MS identification of binding partner confirmed by Co-IP, direct GTPase activation assays with dependency rescue, in vivo xenograft; multiple orthogonal methods","pmids":["36693952"],"is_preprint":false},{"year":2024,"finding":"NRBP1 promotes GBM malignant phenotypes (proliferation, invasion, migration, apoptosis resistance) through activation of the PI3K/Akt signaling pathway. The effects of NRBP1 knockout and overexpression on GBM cells were rescued by PI3K/Akt inhibitor MK-2206 and activator SC79, respectively, establishing epistatic placement of NRBP1 upstream of PI3K/Akt.","method":"NRBP1 knockout and overexpression, pharmacological epistasis (MK-2206, SC79), cell proliferation/invasion/migration assays, mouse tumor model","journal":"Cancer medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with pharmacological rescue; single lab, multiple functional readouts","pmids":["39149873"],"is_preprint":false},{"year":2024,"finding":"NRBP1, TSC22D2, and WNK1 physically associate into biomolecular condensates within seconds of hyperosmotic stress, dependent on intrinsically disordered regions (IDRs). NRBP1 contains a domain (NbrT, NRBP binding region with TSC22D) that specifically evolved to bind TSC22D proteins, co-evolving with WNK IDR expansion in metazoans. All three gene families are functionally buffered for osmo-sensing and cell volume control.","method":"Gene co-essentiality analysis, live-cell imaging of condensate formation, co-IP, domain mapping (NbrT identification), phylogenetic analysis","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct imaging of condensate formation, co-IP, domain mapping, and evolutionary analysis across multiple orthogonal methods; replicated across gene families","pmids":["38980795"],"is_preprint":false},{"year":2024,"finding":"The NRBP1 CCT-like domain binds TSC22D1 via the same R-F-x-V/I or R-x-F-x-V/I motif used by OSR1 and SPAK, identifying NRBP1 as a WNK pathway component that interacts with TSC22D scaffold proteins through conserved CCT domain-motif interactions.","method":"Computational motif prediction, in vitro binding assays, comparison with known CCT domain interactions","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — experimental binding assay validating computational prediction; preprint, single lab","pmids":["bio_10.1101_2024.06.26.600905"],"is_preprint":true},{"year":2025,"finding":"NRBP1 pseudokinase directly activates WNK4 in vitro and is required for basal and sorbitol-induced activation of WNK1 and downstream SPAK/OXSR1 components. NRBP1 associates with WNK1 and TSC22D2/4 following osmotic stress (confirmed by immunoprecipitation, MS, immunoblotting). NRBP1 contains a CCT domain that, per AlphaFold-3 modeling, interacts with TSC22D4 RΦ-motifs alongside WNK1 CCTL1 domain in a multi-protein complex. NRBP1 knockdown or knockout markedly inhibits WNK pathway activation.","method":"Proximity labeling, Co-IP, mass spectrometry, immunoblotting, in vitro WNK4 activation assay with recombinant NRBP1, siRNA/CRISPR knockout, AlphaFold-3 structural modeling","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro reconstitution of WNK4 activation by recombinant NRBP1, proximity labeling confirmed by Co-IP/MS, genetic loss-of-function, structural modeling; multiple orthogonal methods in rigorous study","pmids":["40668933"],"is_preprint":false},{"year":2025,"finding":"NRBP1 and long TSC22D isoforms (TSC22D1.1, TSC22D2) are localized in WNK bodies (cytoplasmic biomolecular condensates) in the distal convoluted tubule (DCT). NRBP1 and long TSC22D isoforms increase WNK4 activity in HEK293 cells. DCT-specific NRBP1 knockout mice show reduced NCC phosphorylation and activate a compensatory response, demonstrating that NRBP1 modulates Na+ reabsorption in the kidney.","method":"Immunofluorescence/localization in DCT, HEK293 cell WNK4 activity assays, DCT-specific NRBP1 knockout mouse model, NCC phosphorylation measurement","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 / Strong — tissue-specific knockout with defined ion transport phenotype, in vitro kinase activity assay, subcellular localization; replicated with companion paper (PMID:40668933)","pmids":["40668923"],"is_preprint":false},{"year":2025,"finding":"TRIM24 binds NRBP1 and enhances its ubiquitination and subsequent degradation. NRBP1 phosphorylation at residue S42 is crucial for TRIM24-mediated ubiquitination, and K430 is the specific ubiquitination site targeted by TRIM24.","method":"Co-IP, ubiquitination assays, site-directed mutagenesis (S42, K430), siRNA knockdown, Western blot","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct Co-IP, ubiquitination assay, mutagenesis identifying specific residues; single lab","pmids":["41430038"],"is_preprint":false},{"year":2025,"finding":"NRBP1 positively regulates L1 retrotransposition by influencing integrity of the L1 ribonucleoprotein complex. NRBP2 antagonizes NRBP1 function by targeting NRBP1 for degradation, probably through heterodimer formation, rather than by competing for common interaction partners.","method":"L1 retrotransposition assay, NRBP1/NRBP2 overexpression and knockdown, heterodimer formation analysis, phylogenetic analysis","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct functional retrotransposition assay with mechanistic heterodimer degradation evidence; single lab, multiple approaches","pmids":["40645931"],"is_preprint":false},{"year":2017,"finding":"DNA methylation at the NRBP1 promoter region (B1 site, 72 bp upstream of TSS) regulates TFAP2A binding. Hypomethylation reduces TFAP2A binding to B1, leading to increased NRBP1 expression. Methylation increases TFAP2A binding and suppresses gene expression, as shown by luciferase reporter assay and protein pulldown.","method":"Luciferase reporter assay, protein pulldown assay, bisulfite pyrosequencing","journal":"Clinical epigenetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct promoter reporter and pulldown assays; single lab, two orthogonal methods","pmids":["28932319"],"is_preprint":false},{"year":2022,"finding":"NRBP1 negatively regulates SALL4 protein stability in breast cancer cells, and overexpression of SALL4 reverses the NRBP1-overexpression-induced suppression of invasion, migration, apoptosis, and chemotherapy drug sensitivity, establishing NRBP1 acts upstream of SALL4.","method":"NRBP1 overexpression, SALL4 overexpression rescue experiment, Transwell invasion/migration assay, apoptosis assay, drug sensitivity assay (doxorubicin, cisplatin)","journal":"Oncology letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis by rescue experiment, multiple functional readouts; single lab","pmids":["35317026"],"is_preprint":false},{"year":2022,"finding":"NRBP1 modulates ABCG2 (urate transporter) expression in HK-2 kidney cells via activation of the Wnt/β-catenin pathway. Knockdown of NRBP1 increased ABCG2 expression, and this effect was blocked by a β-catenin inhibitor (21H7), demonstrating pathway dependence.","method":"Lentiviral overexpression, siRNA knockdown, qRT-PCR, Western blot, immunofluorescence, β-catenin inhibitor (21H7) epistasis","journal":"Nefrologia","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pharmacological epistasis with a single inhibitor; single lab, limited mechanistic resolution","pmids":["36437206"],"is_preprint":false}],"current_model":"NRBP1 is a pseudokinase/adapter protein that functions as a substrate receptor for Cullin-RING ubiquitin ligase complexes (Cul2/Cul4A) to target substrates (BRI2, BRI3, SALL4) for ubiquitin-mediated degradation, acts as a scaffold that activates Rac1/Cdc42 GTPases via P-Rex1, serves as an upstream activator of the WNK-SPAK/OSR1 kinase pathway (directly activating WNK4 in vitro) by forming biomolecular condensates with WNK kinases and TSC22D proteins in response to osmotic stress, and negatively regulates AP-1 transcriptional activity through interaction with Jab1/CSN5; collectively, these functions implicate NRBP1 in cell volume regulation, ion homeostasis, protein turnover, subcellular trafficking, and oncogenic signaling."},"narrative":{"mechanistic_narrative":"NRBP1 is a multidomain pseudokinase/adapter protein that integrates ubiquitin-dependent protein turnover, small-GTPase signaling, and osmotic stress sensing, having been originally characterized as a putative adapter bearing LXXLL nuclear-receptor-binding motifs, a kinase-like domain, and a bipartite NLS [PMID:10843813]. As a substrate receptor, dimerized NRBP1 assembles a heterodimeric Cul2/Cul4A Cullin-RING ubiquitin ligase whose formation is enhanced by the chaperone-like activity of TSC22D3/TSC22D4, targeting BRI2 and BRI3 for degradation and thereby controlling Aβ production [PMID:32160551]; the same E3 activity drives ubiquitination and degradation of the stemness factor SALL4 [PMID:31864704, PMID:35317026]. NRBP1 also acts as a scaffold for Rho-family GTPase signaling, binding P-Rex1, Rac1, and Cdc42 to promote Rac1/Cdc42 activation, ROS generation, and cell migration and invasion in a P-Rex1-dependent manner [PMID:36693952]. In the WNK-SPAK/OSR1 osmotic stress pathway, NRBP1 uses a CCT-like domain to bind TSC22D scaffold proteins through conserved RΦ-motifs and, together with WNK1 and TSC22D2/4, condenses into intrinsically-disordered-region-dependent biomolecular condensates (WNK bodies) within seconds of hyperosmotic stress [PMID:38980795, PMID:40668933, PMID:40668923]; recombinant NRBP1 directly activates WNK4 in vitro and is required for basal and sorbitol-induced WNK1-SPAK/OXSR1 activation, and DCT-specific deletion in mice reduces NCC phosphorylation and Na+ reabsorption [PMID:40668933, PMID:40668923]. NRBP1 additionally inhibits Jab1/CSN5-induced c-Jun phosphorylation and AP-1 activation [PMID:17052710]. NRBP1 abundance is itself controlled by TRIM24-mediated, S42-phosphorylation-dependent ubiquitination at K430 and by NRBP2, which antagonizes NRBP1 via heterodimer-driven degradation [PMID:41430038, PMID:40645931].","teleology":[{"year":2000,"claim":"Established NRBP1 as a candidate multidomain adapter, defining the domain architecture (LXXLL motifs, pseudokinase domain, NLS) that framed all subsequent functional hypotheses.","evidence":"cDNA cloning, in vitro translation, and domain analysis","pmids":["10843813"],"confidence":"Medium","gaps":["No binding partners or catalytic activity demonstrated","Functional role unaddressed"]},{"year":2002,"claim":"First linked NRBP1 to Rho-family GTPase signaling and secretory trafficking, showing it associates with activated Rac3 and alters ER-to-Golgi transport.","evidence":"Co-IP with V12Rac3, kinase activity assay, and immunocytochemistry in COS-1 cells","pmids":["11956649"],"confidence":"Medium","gaps":["Source of associated kinase activity not resolved","Mechanism linking GTPase binding to trafficking unclear"]},{"year":2006,"claim":"Identified a transcriptional regulatory role, showing NRBP1 binds Jab1/CSN5 and suppresses AP-1 activation.","evidence":"In vivo Co-IP and AP-1 reporter / c-Jun phosphorylation assays","pmids":["17052710"],"confidence":"Medium","gaps":["Structural basis of Jab1 interaction unknown","Relationship to NRBP1's other functions unexplored"]},{"year":2020,"claim":"Defined NRBP1 as a CRL substrate receptor, reconstituting a heterodimeric Cul2/Cul4A ligase that degrades BRI2/BRI3 and showing TSC22D3/4 act as assembly chaperones — linking NRBP1 to Aβ production.","evidence":"CRL reconstitution, MS interactome, RNAi knockdown with Aβ readout","pmids":["32160551"],"confidence":"High","gaps":["In vivo relevance to amyloid pathology not tested","Full substrate repertoire undefined"]},{"year":2019,"claim":"Extended NRBP1's E3 substrate-receptor role to oncogenesis by showing it ubiquitinates SALL4, with THG-1 competing to stabilize SALL4 and promote tumor stemness.","evidence":"Ubiquitination and competitive binding assays, tumorsphere formation in ESCC cells","pmids":["31864704"],"confidence":"Medium","gaps":["Cullin scaffold used for SALL4 not directly identified","Single cancer context"]},{"year":2023,"claim":"Established NRBP1 as a scaffold that drives Rac1/Cdc42 activation and oncogenic migration/invasion through P-Rex1.","evidence":"BioID/MS, Co-IP, GTPase pull-down activity assays, P-Rex1-dependent rescue, ROS measurement, xenografts","pmids":["36693952"],"confidence":"High","gaps":["Whether NRBP1 directly activates P-Rex1 GEF activity not resolved","Connection to its E3 functions unknown"]},{"year":2024,"claim":"Resolved the molecular basis of NRBP1 recruitment to the WNK osmotic-stress pathway, identifying CCT/NbrT domain-motif binding to TSC22D and rapid IDR-dependent condensate formation with WNK1.","evidence":"Co-essentiality analysis, live-cell condensate imaging, co-IP, domain mapping, phylogenetics; in vitro CCT-motif binding (one preprint)","pmids":["38980795","bio_10.1101_2024.06.26.600905"],"confidence":"High","gaps":["Functional consequence of condensation for kinase activity not yet shown in these reports","Stoichiometry of the condensate undefined"]},{"year":2025,"claim":"Demonstrated NRBP1 is a direct activator of WNK kinases and a physiological regulator of renal Na+ handling, showing recombinant NRBP1 activates WNK4 in vitro and DCT-specific deletion reduces NCC phosphorylation.","evidence":"In vitro WNK4 activation with recombinant NRBP1, proximity labeling/Co-IP/MS, CRISPR knockout, AlphaFold-3 modeling, DCT-specific knockout mice with NCC phosphorylation readout","pmids":["40668933","40668923"],"confidence":"High","gaps":["Mechanism by which a pseudokinase activates WNK4 catalysis is unresolved","Whether the same activity governs WNK signaling in non-renal tissues untested"]},{"year":2025,"claim":"Identified upstream control of NRBP1 abundance, showing TRIM24 mediates S42-phosphorylation-dependent K430 ubiquitination and NRBP2 antagonizes NRBP1 by heterodimer-driven degradation.","evidence":"Co-IP, ubiquitination assays, site-directed mutagenesis, L1 retrotransposition assays, NRBP1/NRBP2 perturbation","pmids":["41430038","40645931"],"confidence":"Medium","gaps":["Kinase phosphorylating S42 not identified","Physiological trigger of TRIM24/NRBP2-mediated turnover unknown"]},{"year":null,"claim":"How NRBP1's distinct activities — CRL substrate receptor, GTPase scaffold, and WNK pathway activator — are coordinated or partitioned within a cell remains unknown.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model integrating the multiple functional modules","Unknown whether condensate localization gates E3 versus GTPase functions","Catalytic mechanism of pseudokinase-driven WNK activation unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[3,4,11]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[3,7,9]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[7,11,2]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[9,12]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[3,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[7,11,8]},{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[9,11,12]}],"complexes":["Cul2/Cul4A heterodimeric Cullin-RING ligase","WNK body / NRBP1-WNK1-TSC22D condensate"],"partners":["TSC22D3","TSC22D4","WNK1","TSC22D2","P-REX1","RAC1","JAB1","TRIM24"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9UHY1","full_name":"Nuclear receptor-binding protein","aliases":[],"length_aa":535,"mass_kda":59.8,"function":"Required for embryonic development (By similarity). Plays a role in intestinal epithelial cell fate and proliferation, thereby involved in the architectural development of the intestine potentially via the regulation of Wnt-responsive genes (By similarity). May play a role in subcellular trafficking between the endoplasmic reticulum and Golgi apparatus through interactions with the Rho-type GTPases (PubMed:11956649). Binding to the NS3 protein of dengue virus type 2 appears to subvert this activity into the alteration of the intracellular membrane structure associated with flaviviral replication (PubMed:15084397)","subcellular_location":"Cytoplasm, cell cortex; Endomembrane system; Cell projection, lamellipodium","url":"https://www.uniprot.org/uniprotkb/Q9UHY1/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/NRBP1","classification":"Common Essential","n_dependent_lines":1103,"n_total_lines":1208,"dependency_fraction":0.9130794701986755},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000115216","cell_line_id":"CID001228","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"nucleoplasm","grade":1}],"interactors":[{"gene":"TSC22D2","stoichiometry":10.0},{"gene":"TCEB2","stoichiometry":10.0},{"gene":"TSC22D1","stoichiometry":10.0},{"gene":"CAPZB","stoichiometry":0.2},{"gene":"TCEB1","stoichiometry":0.2},{"gene":"RBM25","stoichiometry":0.2},{"gene":"TSC22D3","stoichiometry":0.2},{"gene":"TSC22D4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001228","total_profiled":1310},"omim":[{"mim_id":"606010","title":"NUCLEAR RECEPTOR-BINDING PROTEIN 1; NRBP1","url":"https://www.omim.org/entry/606010"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NRBP1"},"hgnc":{"alias_symbol":["BCON3","MUDPNP","MADM"],"prev_symbol":["NRBP"]},"alphafold":{"accession":"Q9UHY1","domains":[{"cath_id":"3.30.200.20","chopping":"52-150","consensus_level":"medium","plddt":83.9957,"start":52,"end":150},{"cath_id":"1.10.510.10","chopping":"157-322","consensus_level":"medium","plddt":83.5345,"start":157,"end":322},{"cath_id":"3.10.20.90","chopping":"443-524","consensus_level":"high","plddt":84.651,"start":443,"end":524}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UHY1","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UHY1-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UHY1-F1-predicted_aligned_error_v6.png","plddt_mean":75.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NRBP1","jax_strain_url":"https://www.jax.org/strain/search?query=NRBP1"},"sequence":{"accession":"Q9UHY1","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UHY1.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UHY1/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UHY1"}},"corpus_meta":[{"pmid":"34819637","id":"PMC_34819637","title":"Microglial ERK-NRBP1-CREB-BDNF signaling in sustained antidepressant actions of (R)-ketamine.","date":"2021","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/34819637","citation_count":176,"is_preprint":false},{"pmid":"32160551","id":"PMC_32160551","title":"NRBP1-Containing CRL2/CRL4A Regulates Amyloid β Production by Targeting BRI2 and BRI3 for Degradation.","date":"2020","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/32160551","citation_count":36,"is_preprint":false},{"pmid":"10843813","id":"PMC_10843813","title":"Cloning of the cDNA and localization of the gene encoding human NRBP, a ubiquitously expressed, multidomain putative adapter protein.","date":"2000","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/10843813","citation_count":32,"is_preprint":false},{"pmid":"28932319","id":"PMC_28932319","title":"DNA hypomethylation of a transcription factor binding site within the promoter of a gout risk gene NRBP1 upregulates its expression by inhibition of TFAP2A binding.","date":"2017","source":"Clinical epigenetics","url":"https://pubmed.ncbi.nlm.nih.gov/28932319","citation_count":28,"is_preprint":false},{"pmid":"11956649","id":"PMC_11956649","title":"Interaction of the small GTPase Rac3 with NRBP, a protein with a kinase-homology domain.","date":"2002","source":"International journal of molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/11956649","citation_count":26,"is_preprint":false},{"pmid":"22473923","id":"PMC_22473923","title":"High NRBP1 expression in prostate cancer is linked with poor clinical outcomes and increased cancer cell growth.","date":"2012","source":"The Prostate","url":"https://pubmed.ncbi.nlm.nih.gov/22473923","citation_count":24,"is_preprint":false},{"pmid":"26715855","id":"PMC_26715855","title":"NRBP1 is downregulated in breast cancer and NRBP1 overexpression inhibits cancer cell proliferation through Wnt/β-catenin signaling pathway.","date":"2015","source":"OncoTargets and 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containing two LXXLL nuclear receptor binding motifs, a putative SH2 domain-binding domain, a kinase-like domain, a bipartite nuclear localization signal, and PEST sequences. In vitro translation revealed three products of 60, 51, and 43 kDa, suggesting multiple translation initiation sites.\",\n      \"method\": \"cDNA cloning, in vitro translation, domain analysis\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct biochemical characterization by in vitro translation and domain mapping; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"10843813\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"NRBP1 forms a complex with constitutively activated Rac3 (V12Rac3) and exhibits an associated kinase activity. NRBP and activated Rac3 co-localize to endomembranes and at the cell periphery in lamellipodia. Overexpression of NRBP caused redistribution of Golgi-associated marker p58 to more peripheral locations, consistent with impairment of ER-to-Golgi transport, suggesting a role in subcellular trafficking.\",\n      \"method\": \"Co-IP/pulldown with V12Rac3, kinase activity assay, immunocytochemistry, overexpression in COS-1 cells\",\n      \"journal\": \"International journal of molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding and kinase assay with co-localization; single lab, multiple methods\",\n      \"pmids\": [\"11956649\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"NRBP1 interacts in vivo with Jab1 (the fifth component of the COP9 signalosome complex) and inhibits Jab1-induced phosphorylation of c-Jun and AP-1 activation. Overexpression of NRBP1 in mammalian cells specifically inhibits AP-1 activation by various stimuli.\",\n      \"method\": \"Co-IP in vivo, AP-1 reporter assay, c-Jun phosphorylation assay, overexpression\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo Co-IP plus functional reporter assay; single lab, two orthogonal methods\",\n      \"pmids\": [\"17052710\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"NRBP1 functions as a substrate receptor of a Cullin-RING ubiquitin ligase (CRL) complex targeting BRI2 and BRI3 for degradation. Dimerized NRBP1 assembles into a functional heterodimeric CRL containing both Cul2 and Cul4A through its BC-box and an overlapping cryptic H-box. Formation of the NRBP1 heterodimeric CRL is strongly enhanced by chaperone-like function of TSC22D3 and TSC22D4. NRBP1 knockdown in neuronal cells increases BRI2 and BRI3 abundance and significantly reduces Aβ production.\",\n      \"method\": \"Co-IP, mass spectrometry, reconstitution of CRL complex, RNAi knockdown, Aβ measurement\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — biochemical reconstitution of CRL complex, MS-based interactome, functional knockdown with defined substrate readout; multiple orthogonal methods in one rigorous study\",\n      \"pmids\": [\"32160551\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"NRBP1 induces ubiquitination of SALL4, targeting it for degradation. THG-1 (a NRBP1 binding protein) competes with SALL4 for NRBP1 binding, thereby blocking NRBP1-mediated ubiquitination of SALL4 and stabilizing it to promote stemness gene expression (NANOG, OCT4) and tumorsphere growth in esophageal squamous cell carcinoma cells.\",\n      \"method\": \"Knockdown and overexpression, ubiquitination assay, competitive binding assay, tumorsphere formation assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct ubiquitination assay with competitive binding; single lab, multiple functional assays\",\n      \"pmids\": [\"31864704\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"NRBP1 is localized in microglia and neurons (not astrocytes) in mouse medial prefrontal cortex. (R)-ketamine increases NRBP1 expression in primary microglia cultures through ERK activation, and NRBP1 participates in an ERK-NRBP1-CREB-BDNF signaling cascade. Microglial depletion blocked the antidepressant-like effects of (R)-ketamine.\",\n      \"method\": \"Isobaric quantitative proteomics (iTRAQ), immunofluorescence/immunohistochemistry for localization, primary microglia culture, ERK inhibition, intracerebroventricular HDO injection, microglial depletion (PLX3397, MCLs)\",\n      \"journal\": \"Molecular psychiatry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — localization by immunofluorescence, pharmacological pathway dissection, functional behavioral readout; single lab, multiple orthogonal approaches\",\n      \"pmids\": [\"34819637\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Drosophila Madm (ortholog of NRBP1) is required presynaptically to maintain synaptic stability and coordinate synaptic growth and function by controlling cap-dependent translation via the TOR effector 4E-BP/Thor. Postsynaptic Madm induces a compensatory transsynaptic signal using the presynaptic homeostatic potentiation (PHP) machinery to offset synaptic release deficits at degenerating neuromuscular synapses, acting via regulation of cap-dependent translation regulators 4E-BP/Thor and S6-kinase.\",\n      \"method\": \"Genetic loss-of-function (presynaptic and postsynaptic specific knockdown), electrophysiology, imaging of neuromuscular junction, epistasis with TOR pathway components\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis, compartment-specific knockdowns, electrophysiological readout, and mechanistic rescue experiments across multiple orthogonal approaches\",\n      \"pmids\": [\"36450258\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"NRBP1 (pseudokinase) acts as a scaffold that binds P-Rex1 (a guanine nucleotide exchange factor for Rac1), Rac1, and Cdc42. NRBP1 overexpression enhances GTP-bound Rac1 and Cdc42 levels in a P-Rex1-dependent manner, while NRBP1 knockdown reduces their activation. NRBP1-mediated promotion of cell migration and invasion is P-Rex1-dependent. Generation of reactive oxygen species via a NRBP1/P-Rex1 pathway is implicated in oncogenic roles.\",\n      \"method\": \"BioID/MS proximity labeling, Co-IP, GTP-Rac1/Cdc42 pull-down activity assays, siRNA knockdown, P-Rex1-dependent rescue experiments, ROS measurement, xenograft models\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — BioID/MS identification of binding partner confirmed by Co-IP, direct GTPase activation assays with dependency rescue, in vivo xenograft; multiple orthogonal methods\",\n      \"pmids\": [\"36693952\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NRBP1 promotes GBM malignant phenotypes (proliferation, invasion, migration, apoptosis resistance) through activation of the PI3K/Akt signaling pathway. The effects of NRBP1 knockout and overexpression on GBM cells were rescued by PI3K/Akt inhibitor MK-2206 and activator SC79, respectively, establishing epistatic placement of NRBP1 upstream of PI3K/Akt.\",\n      \"method\": \"NRBP1 knockout and overexpression, pharmacological epistasis (MK-2206, SC79), cell proliferation/invasion/migration assays, mouse tumor model\",\n      \"journal\": \"Cancer medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with pharmacological rescue; single lab, multiple functional readouts\",\n      \"pmids\": [\"39149873\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NRBP1, TSC22D2, and WNK1 physically associate into biomolecular condensates within seconds of hyperosmotic stress, dependent on intrinsically disordered regions (IDRs). NRBP1 contains a domain (NbrT, NRBP binding region with TSC22D) that specifically evolved to bind TSC22D proteins, co-evolving with WNK IDR expansion in metazoans. All three gene families are functionally buffered for osmo-sensing and cell volume control.\",\n      \"method\": \"Gene co-essentiality analysis, live-cell imaging of condensate formation, co-IP, domain mapping (NbrT identification), phylogenetic analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct imaging of condensate formation, co-IP, domain mapping, and evolutionary analysis across multiple orthogonal methods; replicated across gene families\",\n      \"pmids\": [\"38980795\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The NRBP1 CCT-like domain binds TSC22D1 via the same R-F-x-V/I or R-x-F-x-V/I motif used by OSR1 and SPAK, identifying NRBP1 as a WNK pathway component that interacts with TSC22D scaffold proteins through conserved CCT domain-motif interactions.\",\n      \"method\": \"Computational motif prediction, in vitro binding assays, comparison with known CCT domain interactions\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — experimental binding assay validating computational prediction; preprint, single lab\",\n      \"pmids\": [\"bio_10.1101_2024.06.26.600905\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"NRBP1 pseudokinase directly activates WNK4 in vitro and is required for basal and sorbitol-induced activation of WNK1 and downstream SPAK/OXSR1 components. NRBP1 associates with WNK1 and TSC22D2/4 following osmotic stress (confirmed by immunoprecipitation, MS, immunoblotting). NRBP1 contains a CCT domain that, per AlphaFold-3 modeling, interacts with TSC22D4 RΦ-motifs alongside WNK1 CCTL1 domain in a multi-protein complex. NRBP1 knockdown or knockout markedly inhibits WNK pathway activation.\",\n      \"method\": \"Proximity labeling, Co-IP, mass spectrometry, immunoblotting, in vitro WNK4 activation assay with recombinant NRBP1, siRNA/CRISPR knockout, AlphaFold-3 structural modeling\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro reconstitution of WNK4 activation by recombinant NRBP1, proximity labeling confirmed by Co-IP/MS, genetic loss-of-function, structural modeling; multiple orthogonal methods in rigorous study\",\n      \"pmids\": [\"40668933\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"NRBP1 and long TSC22D isoforms (TSC22D1.1, TSC22D2) are localized in WNK bodies (cytoplasmic biomolecular condensates) in the distal convoluted tubule (DCT). NRBP1 and long TSC22D isoforms increase WNK4 activity in HEK293 cells. DCT-specific NRBP1 knockout mice show reduced NCC phosphorylation and activate a compensatory response, demonstrating that NRBP1 modulates Na+ reabsorption in the kidney.\",\n      \"method\": \"Immunofluorescence/localization in DCT, HEK293 cell WNK4 activity assays, DCT-specific NRBP1 knockout mouse model, NCC phosphorylation measurement\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — tissue-specific knockout with defined ion transport phenotype, in vitro kinase activity assay, subcellular localization; replicated with companion paper (PMID:40668933)\",\n      \"pmids\": [\"40668923\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TRIM24 binds NRBP1 and enhances its ubiquitination and subsequent degradation. NRBP1 phosphorylation at residue S42 is crucial for TRIM24-mediated ubiquitination, and K430 is the specific ubiquitination site targeted by TRIM24.\",\n      \"method\": \"Co-IP, ubiquitination assays, site-directed mutagenesis (S42, K430), siRNA knockdown, Western blot\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct Co-IP, ubiquitination assay, mutagenesis identifying specific residues; single lab\",\n      \"pmids\": [\"41430038\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"NRBP1 positively regulates L1 retrotransposition by influencing integrity of the L1 ribonucleoprotein complex. NRBP2 antagonizes NRBP1 function by targeting NRBP1 for degradation, probably through heterodimer formation, rather than by competing for common interaction partners.\",\n      \"method\": \"L1 retrotransposition assay, NRBP1/NRBP2 overexpression and knockdown, heterodimer formation analysis, phylogenetic analysis\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct functional retrotransposition assay with mechanistic heterodimer degradation evidence; single lab, multiple approaches\",\n      \"pmids\": [\"40645931\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"DNA methylation at the NRBP1 promoter region (B1 site, 72 bp upstream of TSS) regulates TFAP2A binding. Hypomethylation reduces TFAP2A binding to B1, leading to increased NRBP1 expression. Methylation increases TFAP2A binding and suppresses gene expression, as shown by luciferase reporter assay and protein pulldown.\",\n      \"method\": \"Luciferase reporter assay, protein pulldown assay, bisulfite pyrosequencing\",\n      \"journal\": \"Clinical epigenetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct promoter reporter and pulldown assays; single lab, two orthogonal methods\",\n      \"pmids\": [\"28932319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"NRBP1 negatively regulates SALL4 protein stability in breast cancer cells, and overexpression of SALL4 reverses the NRBP1-overexpression-induced suppression of invasion, migration, apoptosis, and chemotherapy drug sensitivity, establishing NRBP1 acts upstream of SALL4.\",\n      \"method\": \"NRBP1 overexpression, SALL4 overexpression rescue experiment, Transwell invasion/migration assay, apoptosis assay, drug sensitivity assay (doxorubicin, cisplatin)\",\n      \"journal\": \"Oncology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis by rescue experiment, multiple functional readouts; single lab\",\n      \"pmids\": [\"35317026\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"NRBP1 modulates ABCG2 (urate transporter) expression in HK-2 kidney cells via activation of the Wnt/β-catenin pathway. Knockdown of NRBP1 increased ABCG2 expression, and this effect was blocked by a β-catenin inhibitor (21H7), demonstrating pathway dependence.\",\n      \"method\": \"Lentiviral overexpression, siRNA knockdown, qRT-PCR, Western blot, immunofluorescence, β-catenin inhibitor (21H7) epistasis\",\n      \"journal\": \"Nefrologia\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pharmacological epistasis with a single inhibitor; single lab, limited mechanistic resolution\",\n      \"pmids\": [\"36437206\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NRBP1 is a pseudokinase/adapter protein that functions as a substrate receptor for Cullin-RING ubiquitin ligase complexes (Cul2/Cul4A) to target substrates (BRI2, BRI3, SALL4) for ubiquitin-mediated degradation, acts as a scaffold that activates Rac1/Cdc42 GTPases via P-Rex1, serves as an upstream activator of the WNK-SPAK/OSR1 kinase pathway (directly activating WNK4 in vitro) by forming biomolecular condensates with WNK kinases and TSC22D proteins in response to osmotic stress, and negatively regulates AP-1 transcriptional activity through interaction with Jab1/CSN5; collectively, these functions implicate NRBP1 in cell volume regulation, ion homeostasis, protein turnover, subcellular trafficking, and oncogenic signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NRBP1 is a multidomain pseudokinase/adapter protein that integrates ubiquitin-dependent protein turnover, small-GTPase signaling, and osmotic stress sensing, having been originally characterized as a putative adapter bearing LXXLL nuclear-receptor-binding motifs, a kinase-like domain, and a bipartite NLS [#0]. As a substrate receptor, dimerized NRBP1 assembles a heterodimeric Cul2/Cul4A Cullin-RING ubiquitin ligase whose formation is enhanced by the chaperone-like activity of TSC22D3/TSC22D4, targeting BRI2 and BRI3 for degradation and thereby controlling Aβ production [#3]; the same E3 activity drives ubiquitination and degradation of the stemness factor SALL4 [#4, #16]. NRBP1 also acts as a scaffold for Rho-family GTPase signaling, binding P-Rex1, Rac1, and Cdc42 to promote Rac1/Cdc42 activation, ROS generation, and cell migration and invasion in a P-Rex1-dependent manner [#7]. In the WNK-SPAK/OSR1 osmotic stress pathway, NRBP1 uses a CCT-like domain to bind TSC22D scaffold proteins through conserved RΦ-motifs and, together with WNK1 and TSC22D2/4, condenses into intrinsically-disordered-region-dependent biomolecular condensates (WNK bodies) within seconds of hyperosmotic stress [#9, #11, #12]; recombinant NRBP1 directly activates WNK4 in vitro and is required for basal and sorbitol-induced WNK1-SPAK/OXSR1 activation, and DCT-specific deletion in mice reduces NCC phosphorylation and Na+ reabsorption [#11, #12]. NRBP1 additionally inhibits Jab1/CSN5-induced c-Jun phosphorylation and AP-1 activation [#2]. NRBP1 abundance is itself controlled by TRIM24-mediated, S42-phosphorylation-dependent ubiquitination at K430 and by NRBP2, which antagonizes NRBP1 via heterodimer-driven degradation [#13, #14].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established NRBP1 as a candidate multidomain adapter, defining the domain architecture (LXXLL motifs, pseudokinase domain, NLS) that framed all subsequent functional hypotheses.\",\n      \"evidence\": \"cDNA cloning, in vitro translation, and domain analysis\",\n      \"pmids\": [\"10843813\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No binding partners or catalytic activity demonstrated\", \"Functional role unaddressed\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"First linked NRBP1 to Rho-family GTPase signaling and secretory trafficking, showing it associates with activated Rac3 and alters ER-to-Golgi transport.\",\n      \"evidence\": \"Co-IP with V12Rac3, kinase activity assay, and immunocytochemistry in COS-1 cells\",\n      \"pmids\": [\"11956649\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Source of associated kinase activity not resolved\", \"Mechanism linking GTPase binding to trafficking unclear\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Identified a transcriptional regulatory role, showing NRBP1 binds Jab1/CSN5 and suppresses AP-1 activation.\",\n      \"evidence\": \"In vivo Co-IP and AP-1 reporter / c-Jun phosphorylation assays\",\n      \"pmids\": [\"17052710\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of Jab1 interaction unknown\", \"Relationship to NRBP1's other functions unexplored\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined NRBP1 as a CRL substrate receptor, reconstituting a heterodimeric Cul2/Cul4A ligase that degrades BRI2/BRI3 and showing TSC22D3/4 act as assembly chaperones — linking NRBP1 to Aβ production.\",\n      \"evidence\": \"CRL reconstitution, MS interactome, RNAi knockdown with Aβ readout\",\n      \"pmids\": [\"32160551\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance to amyloid pathology not tested\", \"Full substrate repertoire undefined\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended NRBP1's E3 substrate-receptor role to oncogenesis by showing it ubiquitinates SALL4, with THG-1 competing to stabilize SALL4 and promote tumor stemness.\",\n      \"evidence\": \"Ubiquitination and competitive binding assays, tumorsphere formation in ESCC cells\",\n      \"pmids\": [\"31864704\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cullin scaffold used for SALL4 not directly identified\", \"Single cancer context\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established NRBP1 as a scaffold that drives Rac1/Cdc42 activation and oncogenic migration/invasion through P-Rex1.\",\n      \"evidence\": \"BioID/MS, Co-IP, GTPase pull-down activity assays, P-Rex1-dependent rescue, ROS measurement, xenografts\",\n      \"pmids\": [\"36693952\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether NRBP1 directly activates P-Rex1 GEF activity not resolved\", \"Connection to its E3 functions unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Resolved the molecular basis of NRBP1 recruitment to the WNK osmotic-stress pathway, identifying CCT/NbrT domain-motif binding to TSC22D and rapid IDR-dependent condensate formation with WNK1.\",\n      \"evidence\": \"Co-essentiality analysis, live-cell condensate imaging, co-IP, domain mapping, phylogenetics; in vitro CCT-motif binding (one preprint)\",\n      \"pmids\": [\"38980795\", \"bio_10.1101_2024.06.26.600905\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of condensation for kinase activity not yet shown in these reports\", \"Stoichiometry of the condensate undefined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated NRBP1 is a direct activator of WNK kinases and a physiological regulator of renal Na+ handling, showing recombinant NRBP1 activates WNK4 in vitro and DCT-specific deletion reduces NCC phosphorylation.\",\n      \"evidence\": \"In vitro WNK4 activation with recombinant NRBP1, proximity labeling/Co-IP/MS, CRISPR knockout, AlphaFold-3 modeling, DCT-specific knockout mice with NCC phosphorylation readout\",\n      \"pmids\": [\"40668933\", \"40668923\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which a pseudokinase activates WNK4 catalysis is unresolved\", \"Whether the same activity governs WNK signaling in non-renal tissues untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified upstream control of NRBP1 abundance, showing TRIM24 mediates S42-phosphorylation-dependent K430 ubiquitination and NRBP2 antagonizes NRBP1 by heterodimer-driven degradation.\",\n      \"evidence\": \"Co-IP, ubiquitination assays, site-directed mutagenesis, L1 retrotransposition assays, NRBP1/NRBP2 perturbation\",\n      \"pmids\": [\"41430038\", \"40645931\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Kinase phosphorylating S42 not identified\", \"Physiological trigger of TRIM24/NRBP2-mediated turnover unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NRBP1's distinct activities — CRL substrate receptor, GTPase scaffold, and WNK pathway activator — are coordinated or partitioned within a cell remains unknown.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model integrating the multiple functional modules\", \"Unknown whether condensate localization gates E3 versus GTPase functions\", \"Catalytic mechanism of pseudokinase-driven WNK activation unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [3, 4, 11]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [3, 7, 9]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [7, 11, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [9, 12]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [7, 11, 8]},\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [9, 11, 12]}\n    ],\n    \"complexes\": [\n      \"Cul2/Cul4A heterodimeric Cullin-RING ligase\",\n      \"WNK body / NRBP1-WNK1-TSC22D condensate\"\n    ],\n    \"partners\": [\n      \"TSC22D3\",\n      \"TSC22D4\",\n      \"WNK1\",\n      \"TSC22D2\",\n      \"P-Rex1\",\n      \"Rac1\",\n      \"Jab1\",\n      \"TRIM24\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}