{"gene":"UBASH3B","run_date":"2026-06-10T10:51:56","timeline":{"discoveries":[{"year":2004,"finding":"Sts-1 (UBASH3B) negatively regulates TCR signaling; T cells from Sts-1/Sts-2 double-knockout mice are hyperresponsive with increased ZAP-70 phosphorylation (including ubiquitylated forms) and hyperactivation of downstream signaling proteins, establishing Sts-1 as a critical negative regulator of ZAP-70 in the TCR signaling pathway.","method":"Genetic knockout (Sts-1/Sts-2 double-knockout mice), T cell stimulation assays, immunoblot for ZAP-70 phosphorylation, cytokine production assays, EAE autoimmunity model","journal":"Immunity","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic KO with defined cellular phenotype, replicated across multiple readouts, and independently corroborated by later structural/biochemical work","pmids":["14738763"],"is_preprint":false},{"year":2004,"finding":"Sts-1 (UBASH3B) binds to Cbl via its SH3 domain, binds mono-ubiquitin and the EGFR/Ub chimera via its UBA domain, is recruited into activated EGFR complexes upon ligand stimulation, and inhibits EGFR endocytosis and degradation, resulting in prolonged mitogenic signaling.","method":"Co-immunoprecipitation, pulldown with ubiquitin/EGFR-Ub chimera, receptor internalization assays, endocytic vesicle quantification, cell proliferation and transformation assays, dominant-negative interference","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, domain-specific binding assays, functional receptor internalization readout with multiple orthogonal methods","pmids":["15159412"],"is_preprint":false},{"year":2007,"finding":"Sts-1 (UBASH3B) is a phosphatase belonging to the phosphoglycerate mutase/acid phosphatase (PGM/AcP) histidine phosphatase superfamily; its C-terminal domain dephosphorylates ZAP-70 in vitro, and point mutations inactivating its phosphatase activity also impair its ability to suppress TCR signaling in T cells.","method":"X-ray crystallography of Sts-1 C-terminal domain, in vitro phosphatase assay with ZAP-70, active-site mutagenesis (key catalytic residues), TCR signaling assays in T cells with phosphatase-dead mutants","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — X-ray structure combined with in vitro enzymatic assay and active-site mutagenesis with functional cell-based validation in one study","pmids":["17679096"],"is_preprint":false},{"year":2007,"finding":"The C-terminal PGM-homology domain of Sts-1 (UBASH3B) catalyzes hydrolysis of ecdysteroid and steroid phosphates, confirming broad histidine phosphatase activity; the domain is structurally and functionally related to insect ecdysteroid phosphate phosphatase (EPP).","method":"Molecular modeling, cloning and expression of human Sts-1 PGM domain and Drosophila EPP, in vitro phosphatase activity assay with ecdysteroid/steroid phosphate substrates","journal":"Proteins","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro enzymatic assay in a single study, no mutagenesis validation of active site in this paper","pmids":["17348005"],"is_preprint":false},{"year":2010,"finding":"TULA-2 (UBASH3B) is expressed in platelets, physically associates with Syk, dephosphorylates Syk, and negatively regulates GPVI signaling; TULA-2-knockout mice show hyperphosphorylation of Syk and PLC-γ2, enhanced GPVI-mediated platelet responses, shorter bleeding times, and a prothrombotic phenotype.","method":"Co-immunoprecipitation (TULA-2 with Syk), in vitro dephosphorylation assay, genetic knockout mice, platelet aggregation/activation assays, immunoblot for Syk/PLC-γ2 phosphorylation, bleeding time measurement","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP plus KO mouse with multiple orthogonal functional readouts","pmids":["20585042"],"is_preprint":false},{"year":2010,"finding":"TULA-2 (UBASH3B) shows defined substrate specificity for phosphotyrosyl peptides: class I substrates have Pro at pY-1 and hydrophilic residue at pY-2; class II substrates have acidic residues at pY-1 to pY-3. TULA-2 is highly active toward Syk pY323 and pY352 sites; in GPVI-stimulated TULA-2-KO platelets, Syk Y323 and Y352 phosphorylation is significantly elevated, confirming Syk as a bona fide substrate.","method":"Combinatorial phosphotyrosyl peptide library screening, kinetic analysis of representative peptides, TULA-2 knockout platelets with immunoblot for site-specific Syk phosphorylation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstituted substrate profiling combined with genetic KO validation of specific phosphorylation sites","pmids":["20670933"],"is_preprint":false},{"year":2012,"finding":"TULA-2 (UBASH3B) is recruited to tyrosine-phosphorylated Syk C-terminal tail peptides in mast cells, is present in complexes with Syk after FcεRI activation, and siRNA-mediated knockdown of TULA-2 increases Syk activation-loop phosphorylation, PLC-γ2 phosphorylation, degranulation, and NF-κB/NFAT activation, establishing TULA-2 as a negative regulator of FcεRI signaling.","method":"Phosphopeptide pulldown from mast cell lysates, mass spectrometry identification, immunoprecipitation, far-Western blot, siRNA knockdown, degranulation assay, immunoblot","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (MS identification, Co-IP, siRNA KD with multiple functional readouts) in one study","pmids":["22267732"],"is_preprint":false},{"year":2012,"finding":"TULA-2 (UBASH3B) is the only family member expressed in osteoclasts and negatively regulates osteoclast differentiation and function; its absence increases Syk phosphorylation at Y352 and Y525/526, activates PLC-γ2 downstream of ITAM signaling, and a phosphatase-dead TULA-2 mutant increases osteoclast function, confirming the mechanism requires phosphatase activity.","method":"Genetic double-knockout mice (DKO), skeletal analysis, in vitro osteoclast differentiation assays, immunoblot for Syk and PLC-γ2 phosphorylation, phosphatase-dead TULA-2 overexpression","journal":"Cellular and molecular life sciences","confidence":"High","confidence_rationale":"Tier 2 / Strong — KO mouse with defined phenotype plus phosphatase-dead mutant providing mechanistic validation, multiple orthogonal readouts","pmids":["23149425"],"is_preprint":false},{"year":2013,"finding":"UBASH3B dephosphorylates CBL ubiquitin ligase, inactivating it and leading to EGFR stabilization and up-regulation; this phosphatase activity is required for the invasive and metastatic phenotype of triple-negative breast cancer cells, and UBASH3B is a direct functional target of miR-200a.","method":"Knockdown/overexpression of UBASH3B in TNBC cells, in vitro phosphatase assay with CBL as substrate, immunoblot for CBL phosphorylation and EGFR levels, invasion/migration assays, xenograft models, phosphatase-dead mutant analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vitro phosphatase assay on CBL plus multiple functional readouts (KD, OE, phosphatase-dead mutant, xenograft) in one study","pmids":["23784775"],"is_preprint":false},{"year":2013,"finding":"Substrate-trapping variants of Sts-1 (UBASH3B), generated by mutagenesis of the nucleophilic His380 and general acid Glu490 in the histidine phosphatase active site, bind with high affinity to tyrosine-phosphorylated ZAP-70 from activated T cell lysates, validating ZAP-70 as a direct substrate of the Sts-1 phosphatase active site; vanadate competition confirms substrate trapping occurs through the active site.","method":"Active-site mutagenesis (H380, E490), substrate-trapping pulldown from T cell lysates, immunoblot for phospho-ZAP-70, vanadate competition assay, T cell signaling assay with overexpressed trapping mutants","journal":"The FEBS journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — active-site mutagenesis combined with substrate-trapping pulldown and vanadate competition, single lab but multiple orthogonal validations","pmids":["24256567"],"is_preprint":false},{"year":2015,"finding":"UBASH3B/Sts-1 is upregulated by AML1-ETO through transcriptional and miR-9-mediated regulation; UBASH3B depletion induces aberrant CBL phosphorylation and impairs proliferation of AML1-ETO cells; this growth inhibition is rescued by CBL mutants, demonstrating that UBASH3B supports AML1-ETO leukemia cell growth partly by modulating CBL phosphorylation state.","method":"shRNA depletion of UBASH3B, ectopic expression of CBL mutants (rescue experiment), immunoblot for CBL phosphorylation, proliferation assays, xenograft model, transcriptional analysis","journal":"Leukemia","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis via rescue experiment with CBL mutants, single lab, two orthogonal methods","pmids":["26449661"],"is_preprint":false},{"year":2015,"finding":"STS-1 (UBASH3B) promotes IFN-α-induced autophagy in B cells by inhibiting CBL phosphorylation, thereby de-repressing TYK2 phosphorylation and enhancing JAK1-STAT1 signaling; JAK1 and STAT1 inhibitors block the STS-1-promoted autophagy, placing STS-1 upstream of JAK1-STAT1 in this pathway.","method":"Overexpression and knockdown of STS-1 in B cells, immunoblot for CBL/TYK2/JAK1/STAT1 phosphorylation, autophagy assays (LC3 conversion), pharmacological inhibition of JAK1/STAT1","journal":"European journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis via inhibitor rescue, immunoblot pathway mapping, single lab with multiple readouts","pmids":["25959715"],"is_preprint":false},{"year":2016,"finding":"UBASH3B acts as a ubiquitin receptor that interacts with ubiquitylated Aurora B and controls Aurora B subcellular localization (recruitment to mitotic microtubules prior to anaphase) without affecting Aurora B protein levels; this activity is required for timely and faithful chromosome segregation in human cells.","method":"Co-immunoprecipitation of UBASH3B with ubiquitylated Aurora B, live-cell imaging of Aurora B localization, loss-of-function (siRNA/KO), gain-of-function, chromosome segregation fidelity assays","journal":"Developmental cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP identifying ubiquitylated substrate, direct localization imaging with functional consequence, LOF and GOF in human cells with defined mitotic phenotype","pmids":["26766443"],"is_preprint":false},{"year":2016,"finding":"TULA-2 (UBASH3B) suppresses Syk activation through GPVI-FcRγ largely by dephosphorylating Syk Tyr346 (regulatory site phosphorylated early after receptor ligation) with high efficiency; it is less efficient at other Syk regulatory sites, identifying Tyr346 dephosphorylation as a key checkpoint in the TULA-2-mediated control of Syk.","method":"In vitro phosphatase assay with site-specific phospho-Syk peptides and proteins, TULA-2-knockout platelet immunoblot for pY346-Syk, GPVI-stimulated platelet signaling assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstituted phosphatase assay with defined site-specific substrates combined with KO validation, replicated across multiple platelet signaling contexts","pmids":["27609517"],"is_preprint":false},{"year":2016,"finding":"TULA-2 (UBASH3B) negatively regulates FcγRIIA signaling in platelets; TULA-2 knockout in FcγRIIA-transgenic mice causes hyperphosphorylation of Syk, LAT, and PLC-γ2, enhanced platelet aggregation/secretion/PS exposure, aggravated thrombocytopenia, and augmented thrombin generation in a HIT model; even heterozygous (50%) reduction of TULA-2 significantly increases platelet reactivity.","method":"Genetic KO crossed with FcγRIIA-transgenic mice, immunoblot for phospho-Syk/LAT/PLCγ2, platelet functional assays, HIT mouse model (antibody-mediated thrombocytopenia), bleeding time","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic KO with defined signaling mechanism and multiple orthogonal in vivo and ex vivo functional readouts","pmids":["27765766"],"is_preprint":false},{"year":2017,"finding":"X-ray crystal structures of the histidine phosphatase domains of human Sts-1 and Sts-2 were determined (unliganded Sts-1HP at 2.5 Å, Sts-1HP/sulfate at 1.9 Å, Sts-2HP/sulfate at 2.4 Å); steady-state kinetics show Sts-1HP has significantly higher phosphatase activity than Sts-2HP; Sts-1HP kinetics mirror full-length Sts-1, confirming it is a functional surrogate; PHPS1 (SHP-1 inhibitor) inhibits Sts-1 with Ki = 1.05 μM; human Sts-1 dephosphorylates ZAP-70 in a cell-based assay.","method":"X-ray crystallography, steady-state kinetic analysis, full-length vs. isolated domain activity comparison, inhibitor Ki determination, cell-based ZAP-70 dephosphorylation assay","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — X-ray structures combined with in vitro kinetics and cell-based functional validation in one rigorous study","pmids":["28759203"],"is_preprint":false},{"year":2017,"finding":"STS-1 (UBASH3B) interacts with ShcA via a phosphotyrosine-dependent interaction, and this interaction is regulated by EGF receptor activation.","method":"Phosphotyrosine-containing peptide affinity pulldown from cell lysates, immunoblot for STS-1, EGF stimulation-dependent comparison","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single pulldown experiment, single lab, no reciprocal Co-IP or functional consequence described","pmids":["28690151"],"is_preprint":false},{"year":2018,"finding":"TULA-2 (UBASH3B) deficiency enhances platelet aggregation, secretion, thromboxane production, and kinetics of signaling downstream of the CLEC-2 (HemITAM) receptor; TULA-2 knockout platelets show enhanced Syk Y346 phosphorylation and downstream PLCγ2/SLP-76 phosphorylation, demonstrating that TULA-2 negatively regulates CLEC-2 signaling by dephosphorylating Syk Y346.","method":"TULA-2 knockout mice, platelet aggregation/secretion assays, immunoblot for pY346-Syk/pPLCγ2/pSLP-76, thromboxane ELISA, stimulation with CLEC-2 antibody and rhodocytin","journal":"TH open","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with defined site-specific phosphorylation readout and multiple functional platelet assays, single lab","pmids":["31249969"],"is_preprint":false},{"year":2020,"finding":"In endothelial cells, TULA-2 (UBASH3B) interacts with SYK and suppresses SYK Y323 phosphorylation; loss of TULA-2 (via miR-25-3p targeting) leads to increased SYK Y323 phosphorylation, which elevates VEGFR-2 Y1175 phosphorylation and promotes angiogenesis.","method":"miR-25-3p overexpression/inhibition, immunoblot for TULA-2/pSYK Y323/pVEGFR-2 Y1175, co-immunoprecipitation of TULA-2 with SYK, in vitro angiogenesis assays, hindlimb ischemia mouse model","journal":"Aging","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP with defined downstream phosphorylation sites and in vivo functional readout, single lab","pmids":["33201836"],"is_preprint":false},{"year":2021,"finding":"UBASH3B (Ubash3b) is induced by TPA treatment and promotes dephosphorylation and subsequent proteasomal degradation of PKCδ protein; RNAi-mediated depletion of Ubash3b blocks TPA-induced PKCδ degradation, establishing Ubash3b as an upstream regulator of PKCδ protein stability through dephosphorylation.","method":"TPA treatment, RNAi knockdown of Ubash3b, immunoblot for PKCδ phosphorylation and protein levels, proteasome inhibition experiment (ALLN), mouse leukemia model","journal":"Biochimie","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KD with defined phosphorylation/degradation readout and proteasome inhibitor epistasis, single lab","pmids":["33556471"],"is_preprint":false},{"year":2024,"finding":"UBASH3B directly binds MRPL12 and dephosphorylates MRPL12 at tyrosine 60 (Y60); loss of Y60 phosphorylation impedes MRPL12 binding to mitochondrial RNA polymerase (POLRMT), downregulating mitochondrial oxidative phosphorylation and inhibiting LUAD tumor progression.","method":"Mass spectrometry identification of MRPL12 Y60 phosphorylation, Co-immunoprecipitation of UBASH3B with MRPL12, in vitro dephosphorylation assay, Y60 mutation analysis (Y60F), POLRMT interaction assay, in vivo LUAD mouse model and patient-derived organoids","journal":"Journal of experimental & clinical cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus site-specific mutagenesis with in vivo functional validation, single lab but multiple model systems","pmids":["39343960"],"is_preprint":false}],"current_model":"UBASH3B (Sts-1/TULA-2) is a multi-domain histidine phosphatase (UBA–SH3–PGM/AcP architecture) that negatively regulates receptor tyrosine kinase and immune receptor signaling by dephosphorylating key tyrosines on substrates including ZAP-70 (TCR), Syk (at Y346/Y352/Y323 in platelets and immune cells), CBL ubiquitin ligase (regulating EGFR stability), PKCδ, and MRPL12 Y60 (mitochondrial metabolism); it also acts as a ubiquitin receptor that recruits ubiquitylated Aurora B to mitotic microtubules to ensure faithful chromosome segregation, and its SH3 and UBA domains mediate protein–protein interactions with Cbl, ShcA, and ubiquitylated substrates."},"narrative":{"mechanistic_narrative":"UBASH3B (Sts-1/TULA-2) is a multi-domain histidine phosphatase of the PGM/acid phosphatase superfamily that acts as a negative regulator of tyrosine kinase signaling across immune, hematopoietic, and other cell types [PMID:17679096, PMID:20585042]. Its catalytic C-terminal domain uses a nucleophilic histidine (His380) and general acid (Glu490) to dephosphorylate specific phosphotyrosines, with substrate selectivity defined by residues flanking the target tyrosine [PMID:24256567, PMID:20670933]. Through this activity it dampens antigen- and immunoreceptor-driven signaling by dephosphorylating ZAP-70 downstream of the TCR [PMID:14738763, PMID:17679096] and Syk downstream of GPVI, FcεRI, FcγRIIA, and CLEC-2 receptors, targeting regulatory sites including Syk Y346, Y323, and Y352 [PMID:20585042, PMID:20670933, PMID:22267732, PMID:27609517]; loss of the phosphatase produces hyperresponsive T cells, mast cells, osteoclasts, and a prothrombotic platelet phenotype [PMID:14738763, PMID:23149425, PMID:27765766]. Independently of direct kinase dephosphorylation, UBASH3B regulates the CBL ubiquitin ligase: its SH3 domain binds Cbl while its UBA domain binds mono-ubiquitin and is recruited into activated EGFR complexes, inhibiting receptor endocytosis and degradation, and its dephosphorylation of CBL stabilizes EGFR to drive proliferative, invasive, and metastatic phenotypes in cancer [PMID:15159412, PMID:23784775]. Beyond receptor signaling, UBASH3B functions as a ubiquitin receptor that recruits ubiquitylated Aurora B to mitotic microtubules to ensure faithful chromosome segregation [PMID:26766443], and it dephosphorylates additional substrates including PKCδ, controlling its proteasomal degradation [PMID:33556471], and the mitochondrial ribosomal protein MRPL12 at Y60 to regulate oxidative phosphorylation [PMID:39343960].","teleology":[{"year":2004,"claim":"Established UBASH3B as a genetic negative regulator of TCR signaling, defining its core role in restraining immunoreceptor activation through control of ZAP-70 phosphorylation.","evidence":"Sts-1/Sts-2 double-knockout mice with T cell stimulation assays, ZAP-70 phospho-immunoblot, and an EAE autoimmunity model","pmids":["14738763"],"confidence":"High","gaps":["Did not resolve whether ZAP-70 is a direct catalytic substrate versus an indirect target","Redundancy with Sts-2 obscured the individual contribution of Sts-1"]},{"year":2004,"claim":"Defined the adaptor/ubiquitin-receptor arm of UBASH3B, showing its SH3 and UBA domains couple it to Cbl, ubiquitin, and the activated EGFR to prolong mitogenic signaling.","evidence":"Co-IP, ubiquitin/EGFR-Ub chimera pulldowns, receptor internalization assays, and dominant-negative interference","pmids":["15159412"],"confidence":"High","gaps":["Did not establish whether EGFR effects required phosphatase activity","Mechanism of recruitment into the EGFR complex not fully resolved"]},{"year":2007,"claim":"Identified the molecular basis of catalysis, placing UBASH3B in the PGM/AcP histidine phosphatase superfamily and tying its enzymatic activity directly to TCR suppression.","evidence":"X-ray crystallography of the C-terminal domain, in vitro phosphatase assay on ZAP-70, active-site mutagenesis, and phosphatase-dead rescue in T cells","pmids":["17679096","17348005"],"confidence":"High","gaps":["Physiological relevance of ecdysteroid/steroid phosphate hydrolysis in mammals unclear","Ecdysteroid activity lacked active-site mutagenesis validation"]},{"year":2010,"claim":"Extended the phosphatase function to platelet biology and defined intrinsic substrate specificity, identifying Syk regulatory tyrosines as bona fide targets.","evidence":"Co-IP of TULA-2 with Syk, in vitro dephosphorylation, combinatorial phosphopeptide library profiling, and KO-platelet site-specific immunoblot","pmids":["20585042","20670933"],"confidence":"High","gaps":["Did not rank which Syk site is rate-limiting in vivo (resolved later)","Specificity rules derived from peptides may not capture full-length substrate context"]},{"year":2012,"claim":"Generalized Syk regulation across immunoreceptor systems, showing UBASH3B restrains FcεRI signaling in mast cells and osteoclast differentiation through phosphatase-dependent control of Syk.","evidence":"Phosphopeptide pulldown/MS, siRNA knockdown with degranulation and NF-κB/NFAT readouts in mast cells; DKO mice and phosphatase-dead mutant in osteoclasts","pmids":["22267732","23149425"],"confidence":"High","gaps":["Did not define site preference within Syk in these cell types","Contribution relative to other Syk phosphatases not quantified"]},{"year":2013,"claim":"Confirmed ZAP-70 as a direct active-site substrate and revealed a CBL-EGFR axis through which UBASH3B drives cancer invasion, linking its phosphatase activity to oncogenic signaling.","evidence":"Substrate-trapping His380/Glu490 mutants with vanadate competition in T cells; CBL in vitro dephosphorylation, phosphatase-dead mutant, and xenografts in TNBC cells","pmids":["24256567","23784775"],"confidence":"High","gaps":["Whether CBL dephosphorylation and EGFR adaptor binding act synergistically not dissected","miR-200a regulation defined only in TNBC context"]},{"year":2015,"claim":"Showed UBASH3B-CBL signaling has context-dependent outputs, supporting leukemia cell growth and shaping IFN-α-induced autophagy through JAK1-STAT1.","evidence":"shRNA depletion with CBL-mutant rescue and xenografts in AML1-ETO cells; overexpression/knockdown with inhibitor epistasis in B cells","pmids":["26449661","25959715"],"confidence":"Medium","gaps":["Single-lab studies without independent confirmation","Direct versus indirect effects on TYK2/JAK1/STAT1 not fully separated"]},{"year":2016,"claim":"Revealed a non-canonical mitotic function as a ubiquitin receptor and refined the platelet substrate map by identifying Syk Y346 as the key dephosphorylation checkpoint.","evidence":"Co-IP of ubiquitylated Aurora B, live-cell imaging, LOF/GOF chromosome segregation assays; site-specific phospho-Syk peptide phosphatase assays and FcγRIIA-transgenic KO mice in platelets","pmids":["26766443","27609517","27765766"],"confidence":"High","gaps":["How the UBA domain selects ubiquitylated Aurora B over other substrates unknown","Whether the mitotic and signaling functions are coordinated unclear"]},{"year":2017,"claim":"Provided comparative structural and kinetic detail distinguishing Sts-1 from Sts-2 and mapped a phosphotyrosine-dependent ShcA interaction at the EGFR.","evidence":"X-ray structures of Sts-1/Sts-2 HP domains with sulfate, steady-state kinetics, PHPS1 inhibitor Ki, cell-based ZAP-70 assay; phosphopeptide affinity pulldown for ShcA","pmids":["28759203","28690151"],"confidence":"High","gaps":["ShcA interaction rests on a single pulldown without reciprocal Co-IP or functional consequence","Functional difference between Sts-1 and Sts-2 in vivo not addressed"]},{"year":2024,"claim":"Broadened the substrate repertoire beyond receptor signaling to CLEC-2/HemITAM platelet signaling, endothelial VEGFR-2-driven angiogenesis, PKCδ stability, and mitochondrial metabolism via MRPL12 Y60.","evidence":"KO platelets (CLEC-2); miR-25-3p modulation with Co-IP and hindlimb ischemia (endothelium); RNAi with proteasome inhibitor (PKCδ); MS, Co-IP, Y60F mutagenesis, POLRMT interaction, and LUAD models (MRPL12)","pmids":["31249969","33201836","33556471","39343960"],"confidence":"Medium","gaps":["Each substrate characterized by a single lab","How UBASH3B accesses a mitochondrial substrate (MRPL12) and its subcellular localization there not resolved"]},{"year":null,"claim":"It remains unresolved how UBASH3B's three activities — phosphotyrosine catalysis, Cbl/ubiquitin adaptor function, and ubiquitin-receptor-mediated cargo recruitment — are integrated and regulated within a single cell.","evidence":"No timeline study addresses coordinated regulation across domains","pmids":[],"confidence":"Low","gaps":["No structural model of the full-length multidomain protein engaging substrate plus ubiquitin","Mechanism selecting between catalytic and adaptor modes unknown","Upstream signals controlling UBASH3B activity/localization largely uncharacterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,2,4,5,8,9,13,19,20]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[2,3,15]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[1,12]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,4,7,14]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1,4]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[12]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[20]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[0,4,6,7,14]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,8,18]},{"term_id":"R-HSA-109582","term_label":"Hemostasis","supporting_discovery_ids":[4,14,17]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[12]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[8,10,20]}],"complexes":[],"partners":["CBL","ZAP70","SYK","AURKB","SHC1","MRPL12","PRKCD","EGFR"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8TF42","full_name":"Ubiquitin-associated and SH3 domain-containing protein B","aliases":["Cbl-interacting protein p70","Suppressor of T-cell receptor signaling 1","STS-1","T-cell ubiquitin ligand 2","TULA-2","Tyrosine-protein phosphatase STS1/TULA2"],"length_aa":649,"mass_kda":72.7,"function":"Interferes with CBL-mediated down-regulation and degradation of receptor-type tyrosine kinases. Promotes accumulation of activated target receptors, such as T-cell receptors and EGFR, on the cell surface. Exhibits tyrosine phosphatase activity toward several substrates including EGFR, FAK, SYK, and ZAP70. Down-regulates proteins that are dually modified by both protein tyrosine phosphorylation and ubiquitination","subcellular_location":"Cytoplasm; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q8TF42/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/UBASH3B","classification":"Not Classified","n_dependent_lines":4,"n_total_lines":1208,"dependency_fraction":0.0033112582781456954},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/UBASH3B","total_profiled":1310},"omim":[{"mim_id":"615951","title":"ZINC FINGER SWIM DOMAIN-CONTAINING PROTEIN 6; ZSWIM6","url":"https://www.omim.org/entry/615951"},{"mim_id":"609201","title":"UBIQUITIN-ASSOCIATED AND SH3 DOMAIN-CONTAINING PROTEIN B; UBASH3B","url":"https://www.omim.org/entry/609201"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Nuclear bodies","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":21.2},{"tissue":"lymphoid tissue","ntpm":14.7},{"tissue":"placenta","ntpm":12.9}],"url":"https://www.proteinatlas.org/search/UBASH3B"},"hgnc":{"alias_symbol":["KIAA1959","STS-1","TULA2","TULA-2"],"prev_symbol":[]},"alphafold":{"accession":"Q8TF42","domains":[{"cath_id":"-","chopping":"44-77","consensus_level":"high","plddt":95.2115,"start":44,"end":77},{"cath_id":"3.90.1140.10","chopping":"89-254_321-331","consensus_level":"high","plddt":93.0992,"start":89,"end":331},{"cath_id":"2.30.30.40","chopping":"264-313","consensus_level":"medium","plddt":88.7202,"start":264,"end":313},{"cath_id":"3.40.50.1240","chopping":"385-394_439-626","consensus_level":"high","plddt":95.5055,"start":385,"end":626}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TF42","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TF42-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TF42-F1-predicted_aligned_error_v6.png","plddt_mean":84.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=UBASH3B","jax_strain_url":"https://www.jax.org/strain/search?query=UBASH3B"},"sequence":{"accession":"Q8TF42","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8TF42.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8TF42/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TF42"}},"corpus_meta":[{"pmid":"14738763","id":"PMC_14738763","title":"Regulation of ZAP-70 activation and TCR signaling by two related proteins, Sts-1 and Sts-2.","date":"2004","source":"Immunity","url":"https://pubmed.ncbi.nlm.nih.gov/14738763","citation_count":153,"is_preprint":false},{"pmid":"15159412","id":"PMC_15159412","title":"Suppressors of T-cell receptor signaling Sts-1 and Sts-2 bind to Cbl and inhibit endocytosis of receptor tyrosine kinases.","date":"2004","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15159412","citation_count":120,"is_preprint":false},{"pmid":"17679096","id":"PMC_17679096","title":"A phosphatase activity of Sts-1 contributes to the suppression of TCR signaling.","date":"2007","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/17679096","citation_count":100,"is_preprint":false},{"pmid":"23784775","id":"PMC_23784775","title":"Protein tyrosine phosphatase UBASH3B is overexpressed in triple-negative breast cancer and promotes invasion and metastasis.","date":"2013","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/23784775","citation_count":64,"is_preprint":false},{"pmid":"20585042","id":"PMC_20585042","title":"A novel histidine tyrosine phosphatase, TULA-2, associates with Syk and negatively regulates GPVI signaling in platelets.","date":"2010","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/20585042","citation_count":61,"is_preprint":false},{"pmid":"26449661","id":"PMC_26449661","title":"UBASH3B/Sts-1-CBL axis regulates myeloid proliferation in human preleukemia induced by AML1-ETO.","date":"2015","source":"Leukemia","url":"https://pubmed.ncbi.nlm.nih.gov/26449661","citation_count":49,"is_preprint":false},{"pmid":"20670933","id":"PMC_20670933","title":"Determination of the substrate specificity of protein-tyrosine phosphatase TULA-2 and identification of Syk as a TULA-2 substrate.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20670933","citation_count":49,"is_preprint":false},{"pmid":"22267732","id":"PMC_22267732","title":"Once phosphorylated, tyrosines in carboxyl terminus of protein-tyrosine kinase Syk interact with signaling proteins, including TULA-2, a negative regulator of mast cell degranulation.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22267732","citation_count":37,"is_preprint":false},{"pmid":"26766443","id":"PMC_26766443","title":"Ubiquitin Receptor Protein UBASH3B Drives Aurora B Recruitment to Mitotic Microtubules.","date":"2016","source":"Developmental cell","url":"https://pubmed.ncbi.nlm.nih.gov/26766443","citation_count":35,"is_preprint":false},{"pmid":"23149425","id":"PMC_23149425","title":"TULA-2, a novel histidine phosphatase, regulates bone remodeling by modulating osteoclast function.","date":"2012","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/23149425","citation_count":33,"is_preprint":false},{"pmid":"25959715","id":"PMC_25959715","title":"STS-1 promotes IFN-α induced autophagy by activating the JAK1-STAT1 signaling pathway in B cells.","date":"2015","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/25959715","citation_count":31,"is_preprint":false},{"pmid":"6661134","id":"PMC_6661134","title":"Medical results from STS 1-4: analysis of body fluids.","date":"1983","source":"Aviation, space, and environmental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/6661134","citation_count":29,"is_preprint":false},{"pmid":"27609517","id":"PMC_27609517","title":"TULA-2 Protein Phosphatase Suppresses Activation of Syk through the GPVI Platelet Receptor for Collagen by Dephosphorylating Tyr(P)346, a Regulatory Site of Syk.","date":"2016","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/27609517","citation_count":28,"is_preprint":false},{"pmid":"27765766","id":"PMC_27765766","title":"TULA-2 (T-Cell Ubiquitin Ligand-2) Inhibits the Platelet Fc Receptor for IgG IIA (FcγRIIA) Signaling Pathway and Heparin-Induced Thrombocytopenia in Mice.","date":"2016","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/27765766","citation_count":23,"is_preprint":false},{"pmid":"24256567","id":"PMC_24256567","title":"Insights into the suppressor of T-cell receptor (TCR) signaling-1 (Sts-1)-mediated regulation of TCR signaling through the use of novel substrate-trapping Sts-1 phosphatase variants.","date":"2013","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/24256567","citation_count":21,"is_preprint":false},{"pmid":"17348005","id":"PMC_17348005","title":"An unsuspected ecdysteroid/steroid phosphatase activity in the key T-cell regulator, Sts-1: surprising relationship to insect ecdysteroid phosphate phosphatase.","date":"2007","source":"Proteins","url":"https://pubmed.ncbi.nlm.nih.gov/17348005","citation_count":20,"is_preprint":false},{"pmid":"33201836","id":"PMC_33201836","title":"miR-25-3p promotes endothelial cell angiogenesis in aging mice via TULA-2/SYK/VEGFR-2 downregulation.","date":"2020","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/33201836","citation_count":13,"is_preprint":false},{"pmid":"28759203","id":"PMC_28759203","title":"Structural and Functional Characterization of the Histidine Phosphatase Domains of Human Sts-1 and Sts-2.","date":"2017","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/28759203","citation_count":13,"is_preprint":false},{"pmid":"39343960","id":"PMC_39343960","title":"UBASH3B-mediated MRPL12 Y60 dephosphorylation inhibits LUAD development by driving mitochondrial metabolism reprogramming.","date":"2024","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/39343960","citation_count":12,"is_preprint":false},{"pmid":"31249969","id":"PMC_31249969","title":"TULA-2 Deficiency Enhances Platelet Functional Responses to CLEC-2 Agonists.","date":"2018","source":"TH open : companion journal to thrombosis and haemostasis","url":"https://pubmed.ncbi.nlm.nih.gov/31249969","citation_count":12,"is_preprint":false},{"pmid":"16511305","id":"PMC_16511305","title":"Crystallization and initial crystal characterization of the C-terminal phosphoglycerate mutase homology domain of Sts-1.","date":"2006","source":"Acta crystallographica. Section F, Structural biology and crystallization communications","url":"https://pubmed.ncbi.nlm.nih.gov/16511305","citation_count":12,"is_preprint":false},{"pmid":"38461240","id":"PMC_38461240","title":"FLI1 induces erythroleukemia through opposing effects on UBASH3A and UBASH3B expression.","date":"2024","source":"BMC cancer","url":"https://pubmed.ncbi.nlm.nih.gov/38461240","citation_count":8,"is_preprint":false},{"pmid":"28690151","id":"PMC_28690151","title":"Identification of STS-1 as a novel ShcA-binding protein.","date":"2017","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/28690151","citation_count":8,"is_preprint":false},{"pmid":"29487893","id":"PMC_29487893","title":"UBASH3B-mediated silencing of the mitotic checkpoint: Therapeutic perspectives in cancer.","date":"2017","source":"Molecular & cellular oncology","url":"https://pubmed.ncbi.nlm.nih.gov/29487893","citation_count":8,"is_preprint":false},{"pmid":"33556471","id":"PMC_33556471","title":"Ubash3b promotes TPA-mediated suppression of leukemogenesis through accelerated downregulation of PKCδ protein.","date":"2021","source":"Biochimie","url":"https://pubmed.ncbi.nlm.nih.gov/33556471","citation_count":7,"is_preprint":false},{"pmid":"30289285","id":"PMC_30289285","title":"Ubiquitin Associated and SH3 Domain Containing B (UBASH3B) Gene Association with Behcet's Disease in Iranian Population.","date":"2018","source":"Current eye research","url":"https://pubmed.ncbi.nlm.nih.gov/30289285","citation_count":6,"is_preprint":false},{"pmid":"29492198","id":"PMC_29492198","title":"UBASH3B promotes tamoxifen resistance and could be negatively regulated by ESR1.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/29492198","citation_count":6,"is_preprint":false},{"pmid":"24587276","id":"PMC_24587276","title":"Enhanced response of T cells from murine gammaherpesvirus 68-infected mice lacking the suppressor of T cell receptor signaling molecules Sts-1 and Sts-2.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24587276","citation_count":4,"is_preprint":false},{"pmid":"37298164","id":"PMC_37298164","title":"STS-1 and STS-2, Multi-Enzyme Proteins Equipped to Mediate Protein-Protein Interactions.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37298164","citation_count":3,"is_preprint":false},{"pmid":"6700189","id":"PMC_6700189","title":"[Medical results from STS 1-4: analysis of body fluids].","date":"1984","source":"Kosmicheskaia biologiia i aviakosmicheskaia meditsina","url":"https://pubmed.ncbi.nlm.nih.gov/6700189","citation_count":2,"is_preprint":false},{"pmid":"40885971","id":"PMC_40885971","title":"Investigating the role of UBASH3B in cancer: structural relevance, physiological functions, and therapeutic possibilities.","date":"2025","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/40885971","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.04.09.648028","title":"Rapid expansion of synaptic complexity as a key contributor to cognitive growth in early humans","date":"2025-04-15","source":"bioRxiv","url":"https://doi.org/10.1101/2025.04.09.648028","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.03.13.25323837","title":"Interrogating DNA methylation associated with Lewy body pathology in a cross brain-region and multi-cohort study","date":"2025-03-14","source":"bioRxiv","url":"https://doi.org/10.1101/2025.03.13.25323837","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":18122,"output_tokens":6060,"usd":0.072633,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":14610,"output_tokens":4970,"usd":0.09865,"stage2_stop_reason":"end_turn"},"total_usd":0.171283,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2004,\n      \"finding\": \"Sts-1 (UBASH3B) negatively regulates TCR signaling; T cells from Sts-1/Sts-2 double-knockout mice are hyperresponsive with increased ZAP-70 phosphorylation (including ubiquitylated forms) and hyperactivation of downstream signaling proteins, establishing Sts-1 as a critical negative regulator of ZAP-70 in the TCR signaling pathway.\",\n      \"method\": \"Genetic knockout (Sts-1/Sts-2 double-knockout mice), T cell stimulation assays, immunoblot for ZAP-70 phosphorylation, cytokine production assays, EAE autoimmunity model\",\n      \"journal\": \"Immunity\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic KO with defined cellular phenotype, replicated across multiple readouts, and independently corroborated by later structural/biochemical work\",\n      \"pmids\": [\"14738763\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Sts-1 (UBASH3B) binds to Cbl via its SH3 domain, binds mono-ubiquitin and the EGFR/Ub chimera via its UBA domain, is recruited into activated EGFR complexes upon ligand stimulation, and inhibits EGFR endocytosis and degradation, resulting in prolonged mitogenic signaling.\",\n      \"method\": \"Co-immunoprecipitation, pulldown with ubiquitin/EGFR-Ub chimera, receptor internalization assays, endocytic vesicle quantification, cell proliferation and transformation assays, dominant-negative interference\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, domain-specific binding assays, functional receptor internalization readout with multiple orthogonal methods\",\n      \"pmids\": [\"15159412\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Sts-1 (UBASH3B) is a phosphatase belonging to the phosphoglycerate mutase/acid phosphatase (PGM/AcP) histidine phosphatase superfamily; its C-terminal domain dephosphorylates ZAP-70 in vitro, and point mutations inactivating its phosphatase activity also impair its ability to suppress TCR signaling in T cells.\",\n      \"method\": \"X-ray crystallography of Sts-1 C-terminal domain, in vitro phosphatase assay with ZAP-70, active-site mutagenesis (key catalytic residues), TCR signaling assays in T cells with phosphatase-dead mutants\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — X-ray structure combined with in vitro enzymatic assay and active-site mutagenesis with functional cell-based validation in one study\",\n      \"pmids\": [\"17679096\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"The C-terminal PGM-homology domain of Sts-1 (UBASH3B) catalyzes hydrolysis of ecdysteroid and steroid phosphates, confirming broad histidine phosphatase activity; the domain is structurally and functionally related to insect ecdysteroid phosphate phosphatase (EPP).\",\n      \"method\": \"Molecular modeling, cloning and expression of human Sts-1 PGM domain and Drosophila EPP, in vitro phosphatase activity assay with ecdysteroid/steroid phosphate substrates\",\n      \"journal\": \"Proteins\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro enzymatic assay in a single study, no mutagenesis validation of active site in this paper\",\n      \"pmids\": [\"17348005\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"TULA-2 (UBASH3B) is expressed in platelets, physically associates with Syk, dephosphorylates Syk, and negatively regulates GPVI signaling; TULA-2-knockout mice show hyperphosphorylation of Syk and PLC-γ2, enhanced GPVI-mediated platelet responses, shorter bleeding times, and a prothrombotic phenotype.\",\n      \"method\": \"Co-immunoprecipitation (TULA-2 with Syk), in vitro dephosphorylation assay, genetic knockout mice, platelet aggregation/activation assays, immunoblot for Syk/PLC-γ2 phosphorylation, bleeding time measurement\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP plus KO mouse with multiple orthogonal functional readouts\",\n      \"pmids\": [\"20585042\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"TULA-2 (UBASH3B) shows defined substrate specificity for phosphotyrosyl peptides: class I substrates have Pro at pY-1 and hydrophilic residue at pY-2; class II substrates have acidic residues at pY-1 to pY-3. TULA-2 is highly active toward Syk pY323 and pY352 sites; in GPVI-stimulated TULA-2-KO platelets, Syk Y323 and Y352 phosphorylation is significantly elevated, confirming Syk as a bona fide substrate.\",\n      \"method\": \"Combinatorial phosphotyrosyl peptide library screening, kinetic analysis of representative peptides, TULA-2 knockout platelets with immunoblot for site-specific Syk phosphorylation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstituted substrate profiling combined with genetic KO validation of specific phosphorylation sites\",\n      \"pmids\": [\"20670933\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"TULA-2 (UBASH3B) is recruited to tyrosine-phosphorylated Syk C-terminal tail peptides in mast cells, is present in complexes with Syk after FcεRI activation, and siRNA-mediated knockdown of TULA-2 increases Syk activation-loop phosphorylation, PLC-γ2 phosphorylation, degranulation, and NF-κB/NFAT activation, establishing TULA-2 as a negative regulator of FcεRI signaling.\",\n      \"method\": \"Phosphopeptide pulldown from mast cell lysates, mass spectrometry identification, immunoprecipitation, far-Western blot, siRNA knockdown, degranulation assay, immunoblot\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (MS identification, Co-IP, siRNA KD with multiple functional readouts) in one study\",\n      \"pmids\": [\"22267732\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"TULA-2 (UBASH3B) is the only family member expressed in osteoclasts and negatively regulates osteoclast differentiation and function; its absence increases Syk phosphorylation at Y352 and Y525/526, activates PLC-γ2 downstream of ITAM signaling, and a phosphatase-dead TULA-2 mutant increases osteoclast function, confirming the mechanism requires phosphatase activity.\",\n      \"method\": \"Genetic double-knockout mice (DKO), skeletal analysis, in vitro osteoclast differentiation assays, immunoblot for Syk and PLC-γ2 phosphorylation, phosphatase-dead TULA-2 overexpression\",\n      \"journal\": \"Cellular and molecular life sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — KO mouse with defined phenotype plus phosphatase-dead mutant providing mechanistic validation, multiple orthogonal readouts\",\n      \"pmids\": [\"23149425\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"UBASH3B dephosphorylates CBL ubiquitin ligase, inactivating it and leading to EGFR stabilization and up-regulation; this phosphatase activity is required for the invasive and metastatic phenotype of triple-negative breast cancer cells, and UBASH3B is a direct functional target of miR-200a.\",\n      \"method\": \"Knockdown/overexpression of UBASH3B in TNBC cells, in vitro phosphatase assay with CBL as substrate, immunoblot for CBL phosphorylation and EGFR levels, invasion/migration assays, xenograft models, phosphatase-dead mutant analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vitro phosphatase assay on CBL plus multiple functional readouts (KD, OE, phosphatase-dead mutant, xenograft) in one study\",\n      \"pmids\": [\"23784775\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Substrate-trapping variants of Sts-1 (UBASH3B), generated by mutagenesis of the nucleophilic His380 and general acid Glu490 in the histidine phosphatase active site, bind with high affinity to tyrosine-phosphorylated ZAP-70 from activated T cell lysates, validating ZAP-70 as a direct substrate of the Sts-1 phosphatase active site; vanadate competition confirms substrate trapping occurs through the active site.\",\n      \"method\": \"Active-site mutagenesis (H380, E490), substrate-trapping pulldown from T cell lysates, immunoblot for phospho-ZAP-70, vanadate competition assay, T cell signaling assay with overexpressed trapping mutants\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — active-site mutagenesis combined with substrate-trapping pulldown and vanadate competition, single lab but multiple orthogonal validations\",\n      \"pmids\": [\"24256567\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"UBASH3B/Sts-1 is upregulated by AML1-ETO through transcriptional and miR-9-mediated regulation; UBASH3B depletion induces aberrant CBL phosphorylation and impairs proliferation of AML1-ETO cells; this growth inhibition is rescued by CBL mutants, demonstrating that UBASH3B supports AML1-ETO leukemia cell growth partly by modulating CBL phosphorylation state.\",\n      \"method\": \"shRNA depletion of UBASH3B, ectopic expression of CBL mutants (rescue experiment), immunoblot for CBL phosphorylation, proliferation assays, xenograft model, transcriptional analysis\",\n      \"journal\": \"Leukemia\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis via rescue experiment with CBL mutants, single lab, two orthogonal methods\",\n      \"pmids\": [\"26449661\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"STS-1 (UBASH3B) promotes IFN-α-induced autophagy in B cells by inhibiting CBL phosphorylation, thereby de-repressing TYK2 phosphorylation and enhancing JAK1-STAT1 signaling; JAK1 and STAT1 inhibitors block the STS-1-promoted autophagy, placing STS-1 upstream of JAK1-STAT1 in this pathway.\",\n      \"method\": \"Overexpression and knockdown of STS-1 in B cells, immunoblot for CBL/TYK2/JAK1/STAT1 phosphorylation, autophagy assays (LC3 conversion), pharmacological inhibition of JAK1/STAT1\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis via inhibitor rescue, immunoblot pathway mapping, single lab with multiple readouts\",\n      \"pmids\": [\"25959715\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"UBASH3B acts as a ubiquitin receptor that interacts with ubiquitylated Aurora B and controls Aurora B subcellular localization (recruitment to mitotic microtubules prior to anaphase) without affecting Aurora B protein levels; this activity is required for timely and faithful chromosome segregation in human cells.\",\n      \"method\": \"Co-immunoprecipitation of UBASH3B with ubiquitylated Aurora B, live-cell imaging of Aurora B localization, loss-of-function (siRNA/KO), gain-of-function, chromosome segregation fidelity assays\",\n      \"journal\": \"Developmental cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP identifying ubiquitylated substrate, direct localization imaging with functional consequence, LOF and GOF in human cells with defined mitotic phenotype\",\n      \"pmids\": [\"26766443\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"TULA-2 (UBASH3B) suppresses Syk activation through GPVI-FcRγ largely by dephosphorylating Syk Tyr346 (regulatory site phosphorylated early after receptor ligation) with high efficiency; it is less efficient at other Syk regulatory sites, identifying Tyr346 dephosphorylation as a key checkpoint in the TULA-2-mediated control of Syk.\",\n      \"method\": \"In vitro phosphatase assay with site-specific phospho-Syk peptides and proteins, TULA-2-knockout platelet immunoblot for pY346-Syk, GPVI-stimulated platelet signaling assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstituted phosphatase assay with defined site-specific substrates combined with KO validation, replicated across multiple platelet signaling contexts\",\n      \"pmids\": [\"27609517\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"TULA-2 (UBASH3B) negatively regulates FcγRIIA signaling in platelets; TULA-2 knockout in FcγRIIA-transgenic mice causes hyperphosphorylation of Syk, LAT, and PLC-γ2, enhanced platelet aggregation/secretion/PS exposure, aggravated thrombocytopenia, and augmented thrombin generation in a HIT model; even heterozygous (50%) reduction of TULA-2 significantly increases platelet reactivity.\",\n      \"method\": \"Genetic KO crossed with FcγRIIA-transgenic mice, immunoblot for phospho-Syk/LAT/PLCγ2, platelet functional assays, HIT mouse model (antibody-mediated thrombocytopenia), bleeding time\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic KO with defined signaling mechanism and multiple orthogonal in vivo and ex vivo functional readouts\",\n      \"pmids\": [\"27765766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"X-ray crystal structures of the histidine phosphatase domains of human Sts-1 and Sts-2 were determined (unliganded Sts-1HP at 2.5 Å, Sts-1HP/sulfate at 1.9 Å, Sts-2HP/sulfate at 2.4 Å); steady-state kinetics show Sts-1HP has significantly higher phosphatase activity than Sts-2HP; Sts-1HP kinetics mirror full-length Sts-1, confirming it is a functional surrogate; PHPS1 (SHP-1 inhibitor) inhibits Sts-1 with Ki = 1.05 μM; human Sts-1 dephosphorylates ZAP-70 in a cell-based assay.\",\n      \"method\": \"X-ray crystallography, steady-state kinetic analysis, full-length vs. isolated domain activity comparison, inhibitor Ki determination, cell-based ZAP-70 dephosphorylation assay\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — X-ray structures combined with in vitro kinetics and cell-based functional validation in one rigorous study\",\n      \"pmids\": [\"28759203\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"STS-1 (UBASH3B) interacts with ShcA via a phosphotyrosine-dependent interaction, and this interaction is regulated by EGF receptor activation.\",\n      \"method\": \"Phosphotyrosine-containing peptide affinity pulldown from cell lysates, immunoblot for STS-1, EGF stimulation-dependent comparison\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single pulldown experiment, single lab, no reciprocal Co-IP or functional consequence described\",\n      \"pmids\": [\"28690151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TULA-2 (UBASH3B) deficiency enhances platelet aggregation, secretion, thromboxane production, and kinetics of signaling downstream of the CLEC-2 (HemITAM) receptor; TULA-2 knockout platelets show enhanced Syk Y346 phosphorylation and downstream PLCγ2/SLP-76 phosphorylation, demonstrating that TULA-2 negatively regulates CLEC-2 signaling by dephosphorylating Syk Y346.\",\n      \"method\": \"TULA-2 knockout mice, platelet aggregation/secretion assays, immunoblot for pY346-Syk/pPLCγ2/pSLP-76, thromboxane ELISA, stimulation with CLEC-2 antibody and rhodocytin\",\n      \"journal\": \"TH open\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with defined site-specific phosphorylation readout and multiple functional platelet assays, single lab\",\n      \"pmids\": [\"31249969\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In endothelial cells, TULA-2 (UBASH3B) interacts with SYK and suppresses SYK Y323 phosphorylation; loss of TULA-2 (via miR-25-3p targeting) leads to increased SYK Y323 phosphorylation, which elevates VEGFR-2 Y1175 phosphorylation and promotes angiogenesis.\",\n      \"method\": \"miR-25-3p overexpression/inhibition, immunoblot for TULA-2/pSYK Y323/pVEGFR-2 Y1175, co-immunoprecipitation of TULA-2 with SYK, in vitro angiogenesis assays, hindlimb ischemia mouse model\",\n      \"journal\": \"Aging\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP with defined downstream phosphorylation sites and in vivo functional readout, single lab\",\n      \"pmids\": [\"33201836\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"UBASH3B (Ubash3b) is induced by TPA treatment and promotes dephosphorylation and subsequent proteasomal degradation of PKCδ protein; RNAi-mediated depletion of Ubash3b blocks TPA-induced PKCδ degradation, establishing Ubash3b as an upstream regulator of PKCδ protein stability through dephosphorylation.\",\n      \"method\": \"TPA treatment, RNAi knockdown of Ubash3b, immunoblot for PKCδ phosphorylation and protein levels, proteasome inhibition experiment (ALLN), mouse leukemia model\",\n      \"journal\": \"Biochimie\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KD with defined phosphorylation/degradation readout and proteasome inhibitor epistasis, single lab\",\n      \"pmids\": [\"33556471\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"UBASH3B directly binds MRPL12 and dephosphorylates MRPL12 at tyrosine 60 (Y60); loss of Y60 phosphorylation impedes MRPL12 binding to mitochondrial RNA polymerase (POLRMT), downregulating mitochondrial oxidative phosphorylation and inhibiting LUAD tumor progression.\",\n      \"method\": \"Mass spectrometry identification of MRPL12 Y60 phosphorylation, Co-immunoprecipitation of UBASH3B with MRPL12, in vitro dephosphorylation assay, Y60 mutation analysis (Y60F), POLRMT interaction assay, in vivo LUAD mouse model and patient-derived organoids\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus site-specific mutagenesis with in vivo functional validation, single lab but multiple model systems\",\n      \"pmids\": [\"39343960\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"UBASH3B (Sts-1/TULA-2) is a multi-domain histidine phosphatase (UBA–SH3–PGM/AcP architecture) that negatively regulates receptor tyrosine kinase and immune receptor signaling by dephosphorylating key tyrosines on substrates including ZAP-70 (TCR), Syk (at Y346/Y352/Y323 in platelets and immune cells), CBL ubiquitin ligase (regulating EGFR stability), PKCδ, and MRPL12 Y60 (mitochondrial metabolism); it also acts as a ubiquitin receptor that recruits ubiquitylated Aurora B to mitotic microtubules to ensure faithful chromosome segregation, and its SH3 and UBA domains mediate protein–protein interactions with Cbl, ShcA, and ubiquitylated substrates.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"UBASH3B (Sts-1/TULA-2) is a multi-domain histidine phosphatase of the PGM/acid phosphatase superfamily that acts as a negative regulator of tyrosine kinase signaling across immune, hematopoietic, and other cell types [#2, #4]. Its catalytic C-terminal domain uses a nucleophilic histidine (His380) and general acid (Glu490) to dephosphorylate specific phosphotyrosines, with substrate selectivity defined by residues flanking the target tyrosine [#9, #5]. Through this activity it dampens antigen- and immunoreceptor-driven signaling by dephosphorylating ZAP-70 downstream of the TCR [#0, #2] and Syk downstream of GPVI, FcεRI, FcγRIIA, and CLEC-2 receptors, targeting regulatory sites including Syk Y346, Y323, and Y352 [#4, #5, #6, #13]; loss of the phosphatase produces hyperresponsive T cells, mast cells, osteoclasts, and a prothrombotic platelet phenotype [#0, #7, #14]. Independently of direct kinase dephosphorylation, UBASH3B regulates the CBL ubiquitin ligase: its SH3 domain binds Cbl while its UBA domain binds mono-ubiquitin and is recruited into activated EGFR complexes, inhibiting receptor endocytosis and degradation, and its dephosphorylation of CBL stabilizes EGFR to drive proliferative, invasive, and metastatic phenotypes in cancer [#1, #8]. Beyond receptor signaling, UBASH3B functions as a ubiquitin receptor that recruits ubiquitylated Aurora B to mitotic microtubules to ensure faithful chromosome segregation [#12], and it dephosphorylates additional substrates including PKCδ, controlling its proteasomal degradation [#19], and the mitochondrial ribosomal protein MRPL12 at Y60 to regulate oxidative phosphorylation [#20].\"\n}\n\nContinuing with the full JSON:\n\n```json\n{\n  \"mechanistic_narrative\": \"UBASH3B (Sts-1/TULA-2) is a multi-domain histidine phosphatase of the PGM/acid phosphatase superfamily that acts as a negative regulator of tyrosine kinase signaling across immune, hematopoietic, and other cell types [#2, #4]. Its catalytic C-terminal domain uses a nucleophilic histidine (His380) and general acid (Glu490) to dephosphorylate specific phosphotyrosines, with substrate selectivity defined by residues flanking the target tyrosine [#9, #5]. Through this activity it dampens antigen- and immunoreceptor-driven signaling by dephosphorylating ZAP-70 downstream of the TCR [#0, #2] and Syk downstream of GPVI, FcεRI, FcγRIIA, and CLEC-2 receptors, targeting regulatory sites including Syk Y346, Y323, and Y352 [#4, #5, #6, #13]; loss of the phosphatase produces hyperresponsive T cells, mast cells, osteoclasts, and a prothrombotic platelet phenotype [#0, #7, #14]. Independently of direct kinase dephosphorylation, UBASH3B regulates the CBL ubiquitin ligase: its SH3 domain binds Cbl while its UBA domain binds mono-ubiquitin and is recruited into activated EGFR complexes, inhibiting receptor endocytosis and degradation, and its dephosphorylation of CBL stabilizes EGFR to drive proliferative, invasive, and metastatic phenotypes in cancer [#1, #8]. Beyond receptor signaling, UBASH3B functions as a ubiquitin receptor that recruits ubiquitylated Aurora B to mitotic microtubules to ensure faithful chromosome segregation [#12], and it dephosphorylates additional substrates including PKCδ, controlling its proteasomal degradation [#19], and the mitochondrial ribosomal protein MRPL12 at Y60 to regulate oxidative phosphorylation [#20].\",\n  \"teleology\": [\n    {\n      \"year\": 2004,\n      \"claim\": \"Established UBASH3B as a genetic negative regulator of TCR signaling, defining its core role in restraining immunoreceptor activation through control of ZAP-70 phosphorylation.\",\n      \"evidence\": \"Sts-1/Sts-2 double-knockout mice with T cell stimulation assays, ZAP-70 phospho-immunoblot, and an EAE autoimmunity model\",\n      \"pmids\": [\"14738763\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve whether ZAP-70 is a direct catalytic substrate versus an indirect target\", \"Redundancy with Sts-2 obscured the individual contribution of Sts-1\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Defined the adaptor/ubiquitin-receptor arm of UBASH3B, showing its SH3 and UBA domains couple it to Cbl, ubiquitin, and the activated EGFR to prolong mitogenic signaling.\",\n      \"evidence\": \"Co-IP, ubiquitin/EGFR-Ub chimera pulldowns, receptor internalization assays, and dominant-negative interference\",\n      \"pmids\": [\"15159412\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish whether EGFR effects required phosphatase activity\", \"Mechanism of recruitment into the EGFR complex not fully resolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Identified the molecular basis of catalysis, placing UBASH3B in the PGM/AcP histidine phosphatase superfamily and tying its enzymatic activity directly to TCR suppression.\",\n      \"evidence\": \"X-ray crystallography of the C-terminal domain, in vitro phosphatase assay on ZAP-70, active-site mutagenesis, and phosphatase-dead rescue in T cells\",\n      \"pmids\": [\"17679096\", \"17348005\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological relevance of ecdysteroid/steroid phosphate hydrolysis in mammals unclear\", \"Ecdysteroid activity lacked active-site mutagenesis validation\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Extended the phosphatase function to platelet biology and defined intrinsic substrate specificity, identifying Syk regulatory tyrosines as bona fide targets.\",\n      \"evidence\": \"Co-IP of TULA-2 with Syk, in vitro dephosphorylation, combinatorial phosphopeptide library profiling, and KO-platelet site-specific immunoblot\",\n      \"pmids\": [\"20585042\", \"20670933\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not rank which Syk site is rate-limiting in vivo (resolved later)\", \"Specificity rules derived from peptides may not capture full-length substrate context\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Generalized Syk regulation across immunoreceptor systems, showing UBASH3B restrains FcεRI signaling in mast cells and osteoclast differentiation through phosphatase-dependent control of Syk.\",\n      \"evidence\": \"Phosphopeptide pulldown/MS, siRNA knockdown with degranulation and NF-κB/NFAT readouts in mast cells; DKO mice and phosphatase-dead mutant in osteoclasts\",\n      \"pmids\": [\"22267732\", \"23149425\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define site preference within Syk in these cell types\", \"Contribution relative to other Syk phosphatases not quantified\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Confirmed ZAP-70 as a direct active-site substrate and revealed a CBL-EGFR axis through which UBASH3B drives cancer invasion, linking its phosphatase activity to oncogenic signaling.\",\n      \"evidence\": \"Substrate-trapping His380/Glu490 mutants with vanadate competition in T cells; CBL in vitro dephosphorylation, phosphatase-dead mutant, and xenografts in TNBC cells\",\n      \"pmids\": [\"24256567\", \"23784775\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CBL dephosphorylation and EGFR adaptor binding act synergistically not dissected\", \"miR-200a regulation defined only in TNBC context\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Showed UBASH3B-CBL signaling has context-dependent outputs, supporting leukemia cell growth and shaping IFN-α-induced autophagy through JAK1-STAT1.\",\n      \"evidence\": \"shRNA depletion with CBL-mutant rescue and xenografts in AML1-ETO cells; overexpression/knockdown with inhibitor epistasis in B cells\",\n      \"pmids\": [\"26449661\", \"25959715\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab studies without independent confirmation\", \"Direct versus indirect effects on TYK2/JAK1/STAT1 not fully separated\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Revealed a non-canonical mitotic function as a ubiquitin receptor and refined the platelet substrate map by identifying Syk Y346 as the key dephosphorylation checkpoint.\",\n      \"evidence\": \"Co-IP of ubiquitylated Aurora B, live-cell imaging, LOF/GOF chromosome segregation assays; site-specific phospho-Syk peptide phosphatase assays and FcγRIIA-transgenic KO mice in platelets\",\n      \"pmids\": [\"26766443\", \"27609517\", \"27765766\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How the UBA domain selects ubiquitylated Aurora B over other substrates unknown\", \"Whether the mitotic and signaling functions are coordinated unclear\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Provided comparative structural and kinetic detail distinguishing Sts-1 from Sts-2 and mapped a phosphotyrosine-dependent ShcA interaction at the EGFR.\",\n      \"evidence\": \"X-ray structures of Sts-1/Sts-2 HP domains with sulfate, steady-state kinetics, PHPS1 inhibitor Ki, cell-based ZAP-70 assay; phosphopeptide affinity pulldown for ShcA\",\n      \"pmids\": [\"28759203\", \"28690151\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"ShcA interaction rests on a single pulldown without reciprocal Co-IP or functional consequence\", \"Functional difference between Sts-1 and Sts-2 in vivo not addressed\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Broadened the substrate repertoire beyond receptor signaling to CLEC-2/HemITAM platelet signaling, endothelial VEGFR-2-driven angiogenesis, PKCδ stability, and mitochondrial metabolism via MRPL12 Y60.\",\n      \"evidence\": \"KO platelets (CLEC-2); miR-25-3p modulation with Co-IP and hindlimb ischemia (endothelium); RNAi with proteasome inhibitor (PKCδ); MS, Co-IP, Y60F mutagenesis, POLRMT interaction, and LUAD models (MRPL12)\",\n      \"pmids\": [\"31249969\", \"33201836\", \"33556471\", \"39343960\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Each substrate characterized by a single lab\", \"How UBASH3B accesses a mitochondrial substrate (MRPL12) and its subcellular localization there not resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how UBASH3B's three activities — phosphotyrosine catalysis, Cbl/ubiquitin adaptor function, and ubiquitin-receptor-mediated cargo recruitment — are integrated and regulated within a single cell.\",\n      \"evidence\": \"No timeline study addresses coordinated regulation across domains\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of the full-length multidomain protein engaging substrate plus ubiquitin\", \"Mechanism selecting between catalytic and adaptor modes unknown\", \"Upstream signals controlling UBASH3B activity/localization largely uncharacterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 2, 4, 5, 8, 9, 13, 19, 20]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [2, 3, 15]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [1, 12]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 4, 7, 14]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 4]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [12]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [20]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 4, 6, 7, 14]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 8, 18]},\n      {\"term_id\": \"R-HSA-109582\", \"supporting_discovery_ids\": [4, 14, 17]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [12]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [8, 10, 20]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CBL\", \"ZAP70\", \"SYK\", \"AURKB\", \"SHC1\", \"MRPL12\", \"PRKCD\", \"EGFR\"],\n    \"other_free_text\": []\n  }\n}\n```","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}