{"gene":"STAU1","run_date":"2026-06-10T07:46:42","timeline":{"discoveries":[{"year":2011,"finding":"STAU1-binding sites on target mRNAs can be formed by imperfect base-pairing between an Alu element in the 3' UTR of an SMD target mRNA and a complementary Alu element in a cytoplasmic polyadenylated lncRNA (named 1/2-sbsRNA), thereby transactivating STAU1-mediated mRNA decay (SMD) in trans.","method":"RNA co-immunoprecipitation, reporter assays, siRNA knockdown, identification of Alu-element base-pairing between lncRNAs and target 3' UTRs","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal RIP, multiple orthogonal methods, widely replicated by subsequent studies across labs","pmids":["21307942"],"is_preprint":false},{"year":2013,"finding":"STAU1 binding to inverted repeat Alu elements (IRAlus) in the 3' UTR of mRNAs inhibits nuclear retention, augmenting nuclear export of IRAlus-containing mRNAs, and also precludes PKR binding to those dsRNA structures, thereby preventing PKR-mediated eIF2α phosphorylation and global translational repression.","method":"siRNA knockdown, nuclear/cytoplasmic fractionation, reporter assays, co-immunoprecipitation, eIF2α phosphorylation assays","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods in one study (fractionation, RIP, phosphorylation assays, reporter assays), single lab","pmids":["23824540"],"is_preprint":false},{"year":2012,"finding":"TDP-43 physically associates with FMRP and STAU1 to form a functional complex that binds the 3' UTR of SIRT1 mRNA (demonstrated by RIP and RNA pulldown), stabilizing SIRT1 mRNA; knockdown of any one of the three proteins reduces SIRT1 mRNA and protein and sensitizes cells to apoptosis.","method":"Co-immunoprecipitation, RNA immunoprecipitation (RIP), RNA pulldown, siRNA knockdown, microarray","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal RIP and pulldown with functional validation, single lab","pmids":["22584570"],"is_preprint":false},{"year":2008,"finding":"Stau1 negatively regulates myogenic differentiation in C2C12 myoblasts; Stau1 knockdown increases myogenin mRNA and protein levels and promotes spontaneous myogenesis, through a mechanism independent of its co-factor Upf1 (Upf1 knockdown did not affect myogenesis).","method":"siRNA knockdown in C2C12 cells, RT-PCR, western blot, myogenin promoter reporter assay, immunofluorescence","journal":"Genes to cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KD with defined cellular phenotype and genetic dissection from Upf1, single lab","pmids":["18422603"],"is_preprint":false},{"year":2011,"finding":"Stau1 binds the 3' UTR of Dvl2 mRNA and stabilizes it in undifferentiated C2C12 myoblasts; Stau1 knockdown shortens the half-life of Dvl2 3' UTR-containing reporter mRNA, and association of Stau1 with Dvl2 3' UTR decreases upon induction of myogenic differentiation, correlating with reduced Dvl2 mRNA levels.","method":"RNA immunoprecipitation, mRNA half-life assay (reporter with Dvl2 3' UTR), siRNA knockdown, RT-PCR, western blot","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RIP plus functional mRNA stability assay with defined 3' UTR construct, single lab","pmids":["22166206"],"is_preprint":false},{"year":2018,"finding":"STAU1 directly binds IBDV genomic double-stranded RNA via its N-terminal moiety (residues 1–468); this binding decreases MDA5 association with viral dsRNA in vitro, attenuating MDA5-dependent IFN-β induction and promoting IBDV replication. A binding-deficient mutant (residues 469–702) failed to suppress IFN-β promoter activity.","method":"In vitro binding assay, co-immunoprecipitation, IFN-β promoter reporter assay, siRNA knockdown, overexpression of deletion mutants","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro binding plus mutagenesis plus functional reporter, single lab","pmids":["29979632"],"is_preprint":false},{"year":2022,"finding":"STAU1 protein levels are downregulated during mitosis by the E3 ubiquitin ligase APC/C; the degradation determinant was mapped to a short FPL-motif (F39PxPxxLxxxxL50) by alanine scanning, and mutation of this motif prevents APC/C-mediated STAU1 degradation. Additionally, TRIM25 (an E3 ubiquitin ligase) was identified by proximity labeling as responsible for degrading STAU1 and MAP4K1 in a FPL-motif-dependent manner.","method":"Alanine scanning mutagenesis, cycloheximide chase, proximity labeling (BioID), proteasome inhibitor assays, mass spectrometry","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — mutagenesis defining degradation motif plus proximity labeling identification of E3 ligase, single lab, multiple methods","pmids":["36232890"],"is_preprint":false},{"year":2022,"finding":"Phosphomimicry at STAU1 serine 20 (S20D mutation) impairs STAU1-mediated translational regulation and mRNA decay, triggers apoptosis in cancer cells, and alters proliferation; even the isolated N-terminal 88-amino-acid fragment (RBD2S20D, lacking RNA-binding activity) induces apoptosis by acting in trans on endogenous STAU1 posttranscriptional functions.","method":"Site-directed mutagenesis (S20D phosphomimetic), overexpression in cancer cell lines, apoptosis assays, polysome profiling, mRNA stability assays","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — mutagenesis with functional phenotypic readouts, multiple assays, single lab","pmids":["35806349"],"is_preprint":false},{"year":2024,"finding":"Endogenous STAU1 forms dynamic cytoplasmic condensates; these condensates recruit MTOR mRNA at its 5' UTR and promote mTOR translation both in vitro and in vivo. Excessive STAU1 condensate formation leads to mTOR hyperactivation and autophagy-lysosome dysfunction, and interference with condensate formation normalizes mTOR levels and restores autophagic flux.","method":"Live-cell imaging of condensates, in vitro translation assay, in vivo mouse models, STAU1 overexpression/knockdown, autophagy flux assays, mTOR pathway western blot","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (live imaging, in vitro translation, in vivo models, functional rescue), single lab with rigorous controls","pmids":["38913026"],"is_preprint":false},{"year":2023,"finding":"STAU1 overexpression in HEK293 cells increases mTOR translation by directly interacting with the MTOR mRNA 5' UTR, activating downstream mTOR targets and impairing autophagic flux; reducing STAU1 in ALS mouse models normalizes mTOR activity and autophagy-related marker proteins.","method":"STAU1 overexpression/knockdown, mTOR 5' UTR binding assay, western blot for mTOR pathway components, mouse model intervention","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct 5' UTR binding assay plus in vivo validation, single lab","pmids":["36652469"],"is_preprint":false},{"year":2022,"finding":"STAU1 indirectly binds the HBV core promoter (CP) via TARDBP (TDP-43) and recruits the SAGA transcriptional coactivator complex to upregulate CP activity; STAU1 also binds HBx protein and stabilizes it in a ubiquitin-independent manner.","method":"TurboID-based proximity labeling, co-immunoprecipitation, ChIP, reporter assays, siRNA knockdown","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — proximity labeling plus co-IP plus reporter assays, single lab","pmids":["35663023"],"is_preprint":false},{"year":2021,"finding":"STAU1 silencing in alveolar rhabdomyosarcoma (ARMS) cells reduces autophagy by destabilizing BECN1 and ATG16L1 mRNAs, and indirectly inhibits JNK signaling via increased DUSP8 expression; pharmacological JNK activation or DUSP8 silencing restores autophagy in STAU1-depleted ARMS cells. In contrast, in non-transformed skeletal muscle cells, STAU1 downregulation activates autophagy in an mTOR-dependent manner.","method":"siRNA knockdown, mRNA stability assay, western blot, JNK pathway pharmacological rescue, STAU1-transgenic mouse skeletal muscle analysis","journal":"Cellular oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — knockdown with defined molecular mechanism and pharmacological rescue, single lab, multiple cell types","pmids":["33899158"],"is_preprint":false},{"year":2024,"finding":"STAU1 stabilizes BACE1 mRNA by binding to its 3' UTR, extending BACE1 mRNA half-life; STAU1 also enhances GADD45B expression, activating P38 MAPK signaling to promote Tau phosphorylation at Ser396 and Thr181, thereby promoting both amyloidogenesis and tauopathy.","method":"STAU1 knockdown/overexpression, mRNA half-life assay, RIP for 3' UTR binding, transcriptome analysis, western blot for P38 MAPK pathway","journal":"Experimental neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RIP plus mRNA stability plus pathway validation, single lab","pmids":["38729552"],"is_preprint":false},{"year":2024,"finding":"GIGYF2 upregulates STAU1, which then stabilizes PTEN mRNA by binding to its 3' UTR, leading to PI3K/AKT pathway inactivation and hepatic insulin resistance; STAU1 silencing prevents GIGYF2-induced PTEN upregulation and restores AKT signaling.","method":"RNA immunoprecipitation (RIP), siRNA knockdown, overexpression, western blot, in vivo high-fat diet mouse model","journal":"Molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RIP demonstrating 3' UTR binding with in vivo validation, single lab","pmids":["39138413"],"is_preprint":false},{"year":2023,"finding":"STAU1 regulates alternative splicing of Pparγ2 pre-mRNA in 3T3-L1 adipocytes, specifically affecting the splicing of exon E1, as demonstrated by RIP and PAR-CLIP showing STAU1 binding to Pparγ2 pre-mRNA; knockdown/overexpression of STAU1 alters adipocyte differentiation and lipid metabolism gene splicing patterns.","method":"RNA immunoprecipitation (RIP), PAR-CLIP, sucrose density gradient centrifugation, RNA-seq for alternative splicing, siRNA knockdown","journal":"Biochimica et biophysica acta. Molecular and cell biology of lipids","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RIP plus PAR-CLIP plus RNA-seq with functional validation, single lab","pmids":["36871938"],"is_preprint":false},{"year":2025,"finding":"DDX50 monomers (formed upon glucose binding) bind STAU1 and redirect it from an RNA-decay-promoting complex with UPF1 to a DDX50-STAU1 ribonucleoprotein complex that stabilizes pro-differentiation mRNAs including JUN, OVOL1, CEBPB, PRDM1, and TINCR, reversing STAU1's canonical SMD role.","method":"Co-immunoprecipitation, RNA pulldown, CLIP-seq, mRNA stability assays, genetic knockdown, in vitro reconstitution of DDX50-STAU1 complex","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus CLIP-seq plus mRNA stability assays, single lab but multiple orthogonal methods","pmids":["39764852"],"is_preprint":false},{"year":2025,"finding":"tRF-3019A competitively binds STAU1 protein, displacing BECN1 mRNA from STAU1, thereby enhancing BECN1 mRNA stability and expression, which promotes autophagy and malignant progression in colon cancer.","method":"RNA pulldown, RNA immunoprecipitation (RIP), western blot, GFP-LC3B autophagy assay, xenograft tumor model","journal":"Cellular signalling","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, pulldown and RIP without reconstitution or mutagenesis validation","pmids":["40268078"],"is_preprint":false},{"year":2025,"finding":"STAU1 reduction inhibits p53-mediated apoptosis and DNA damage responses in multiple cell types (iPSC-derived neurons, mouse cortical neurons, SH-SY5Y cells, fibroblasts); in C9orf72-expanded patient fibroblasts and mouse ALS models with baseline STAU1 overabundance, STAU1 reduction prevents p53-driven pro-apoptotic signaling.","method":"RNAi knockdown, transcriptomic analysis, apoptosis assays (Nutlin-3 and etoposide treatment), p53 pathway western blot, patient-derived fibroblasts, C9orf72 mouse model","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — transcriptomic plus functional rescue across multiple cell types and in vivo model, single lab","pmids":["41145462"],"is_preprint":false},{"year":2026,"finding":"STAU1 directly binds the 3' UTR of ITGB5 mRNA to stabilize it; ITGB5 upregulation increases FOXP3 phosphorylation at serine 418, which activates FOXP3 binding to the STAU1 promoter, creating a STAU1-ITGB5-FOXP3 positive feedback loop driving CRC metastasis.","method":"RIP, RNA stability assay, ChIP, siRNA knockdown, overexpression, in vitro and in vivo metastasis assays","journal":"Cancer letters","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, RIP and ChIP with functional assays but no reconstitution or mutagenesis","pmids":["41796846"],"is_preprint":false},{"year":2026,"finding":"STAU1 binds the 3' UTR of Ucp1 mRNA and promotes its degradation via SMD; adipose-specific STAU1 deletion upregulates UCP1 protein and enhances thermogenesis in mice. The β3 adrenergic receptor/cAMP-PKA pathway modulates STAU1 activity, with cAMP-PKA inhibition downregulating STAU1.","method":"RIP for 3' UTR binding, adipose-specific Stau1 knockout mice, metabolic phenotyping, western blot, pharmacological pathway manipulation","journal":"Metabolism: clinical and experimental","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RIP plus tissue-specific knockout with clear molecular and metabolic phenotype, single lab","pmids":["42242623"],"is_preprint":false},{"year":2026,"finding":"An Alu element in lnc-APUE base-pairs with the Alu element in the 3' UTR of CDH1 mRNA, triggering CDH1 mRNA decay via the STAU1-UPF1 (SMD) pathway; silencing STAU1 or UPF1 abrogates lnc-APUE-mediated CDH1 decay and tumor metastasis promotion.","method":"siRNA knockdown of STAU1/UPF1, Alu element deletion/mutation reporter assays, xenograft mouse model, RIP","journal":"Advanced science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis (STAU1/UPF1 knockdown rescue), Alu mutagenesis, in vivo validation, single lab","pmids":["41632098"],"is_preprint":false}],"current_model":"STAU1 is a double-stranded RNA-binding protein that functions as a central post-transcriptional regulator: it mediates Staufen-mediated mRNA decay (SMD) by binding dsRNA structures in 3' UTRs—including those formed by Alu element base-pairing with lncRNAs—and recruiting UPF1, but can be redirected by DDX50 to stabilize pro-differentiation mRNAs; it also promotes mRNA stability (e.g., BACE1, PTEN, Dvl2, Ucp1) by 3' UTR binding, enhances nuclear export and translation by blocking PKR binding to 3' UTR inverted-repeat Alus, promotes mTOR translation via 5' UTR binding leading to autophagy dysfunction when overabundant, undergoes APC/C- and TRIM25-mediated proteasomal degradation via an FPL-motif, is functionally regulated by phosphorylation at serine 20, and participates in complexes with TDP-43/FMRP and DDX50 that collectively determine whether bound mRNAs are stabilized or degraded."},"narrative":{"mechanistic_narrative":"STAU1 is a double-stranded RNA-binding protein that acts as a bidirectional post-transcriptional regulator, determining whether bound mRNAs are degraded or stabilized depending on its partner complexes [PMID:21307942, PMID:39764852]. In its canonical decay role, STAU1 binds dsRNA structures in 3' UTRs—including those formed in trans by imperfect base-pairing between an Alu element in a target 3' UTR and a complementary Alu in a cytoplasmic lncRNA—and recruits UPF1 to trigger Staufen-mediated mRNA decay (SMD) [PMID:21307942, PMID:41632098]. This SMD activity destabilizes targets such as CDH1 and Ucp1, with the latter linking STAU1 to adipose thermogenesis under β3-adrenergic/cAMP-PKA control [PMID:42242623, PMID:41632098]. Conversely, STAU1 stabilizes numerous transcripts by 3' UTR binding—BACE1, PTEN, and Dvl2 among them—and can be redirected away from the UPF1 decay complex into a DDX50-STAU1 complex that stabilizes pro-differentiation mRNAs, reversing its SMD function [PMID:22166206, PMID:38729552, PMID:39138413, PMID:39764852]. STAU1 binding to inverted-repeat Alu elements additionally augments nuclear export of those mRNAs and blocks PKR access to the dsRNA, preventing PKR-mediated eIF2α phosphorylation and global translational repression [PMID:23824540]. Through dynamic cytoplasmic condensates STAU1 recruits MTOR mRNA at its 5' UTR to promote mTOR translation, such that STAU1 overabundance drives mTOR hyperactivation and autophagy-lysosome dysfunction [PMID:38913026, PMID:36652469]. STAU1 abundance is itself controlled by APC/C- and TRIM25-mediated proteasomal degradation via an FPL-motif and is functionally modulated by phosphorylation at serine 20 [PMID:36232890, PMID:35806349]. STAU1 overabundance promotes p53-driven apoptosis in neuronal disease models including C9orf72-expanded ALS, where its reduction is protective [PMID:41145462].","teleology":[{"year":2008,"claim":"Established that Staufen has an mRNA-regulatory role in cell-fate decisions independent of its known decay cofactor, showing it is not solely an SMD effector.","evidence":"siRNA knockdown in C2C12 myoblasts with myogenin reporter and genetic dissection from Upf1","pmids":["18422603"],"confidence":"Medium","gaps":["Direct mRNA targets mediating the myogenic phenotype not defined in this study","Upf1-independent molecular mechanism not resolved"]},{"year":2011,"claim":"Revealed that STAU1 decay sites can be assembled in trans by Alu-Alu base-pairing between a target 3' UTR and a cytoplasmic lncRNA, explaining how SMD targets are specified without a perfect cis stem-loop.","evidence":"Reciprocal RNA co-IP, reporter assays, and siRNA knockdown identifying 1/2-sbsRNA Alu pairing","pmids":["21307942"],"confidence":"High","gaps":["Genome-wide scope of trans-acting lncRNA-directed SMD not enumerated","Structural basis of imperfect duplex recognition not defined"]},{"year":2011,"claim":"Demonstrated that STAU1 can stabilize rather than degrade a 3' UTR-bound transcript (Dvl2), and that this binding is developmentally regulated, foreshadowing STAU1's dual decay/stabilization output.","evidence":"RIP and reporter mRNA half-life assays in differentiating C2C12 cells","pmids":["22166206"],"confidence":"Medium","gaps":["What switches STAU1 between stabilizing and decay modes not addressed","Single 3' UTR construct"]},{"year":2012,"claim":"Placed STAU1 in a multiprotein RNP with TDP-43 and FMRP that stabilizes a specific target (SIRT1), establishing partner-dependent stabilization with an apoptosis-relevant readout.","evidence":"Co-IP, reciprocal RIP, RNA pulldown, and knockdown with apoptosis assays","pmids":["22584570"],"confidence":"Medium","gaps":["Stoichiometry and assembly order of the TDP-43/FMRP/STAU1 complex unknown","Single lab"]},{"year":2013,"claim":"Showed STAU1 binding to 3' UTR inverted-repeat Alus serves a dual gatekeeping function—promoting nuclear export and excluding PKR to prevent eIF2α-mediated translational shutdown.","evidence":"Nuclear/cytoplasmic fractionation, reporter assays, co-IP, and eIF2α phosphorylation assays","pmids":["23824540"],"confidence":"High","gaps":["Competition kinetics between STAU1 and PKR for IRAlus not quantified","Single lab"]},{"year":2018,"claim":"Defined STAU1 as a direct dsRNA-binding antagonist of innate immune sensing, mapping the activity to its N-terminal moiety that competes with MDA5 for viral dsRNA.","evidence":"In vitro binding, deletion-mutant overexpression, and IFN-β promoter reporter assays in an IBDV system","pmids":["29979632"],"confidence":"Medium","gaps":["Relevance to mammalian antiviral responses not established","Residues mediating MDA5 competition not pinpointed"]},{"year":2022,"claim":"Identified how STAU1 abundance is set, mapping an FPL degron targeted by APC/C during mitosis and by TRIM25, providing a degradative control point on STAU1 activity.","evidence":"Alanine-scanning mutagenesis, cycloheximide chase, proximity labeling, and proteasome inhibition","pmids":["36232890"],"confidence":"Medium","gaps":["Physiological triggers for TRIM25-mediated turnover unclear","Single lab"]},{"year":2022,"claim":"Established phosphorylation at serine 20 as a functional switch on STAU1's post-transcriptional output, with a phosphomimetic N-terminal fragment acting in trans to induce apoptosis.","evidence":"S20D phosphomimetic mutagenesis, polysome profiling, mRNA stability and apoptosis assays in cancer cells","pmids":["35806349"],"confidence":"Medium","gaps":["Kinase responsible for S20 phosphorylation not identified","Mechanism of dominant-negative trans action of the RBD2 fragment unresolved"]},{"year":2022,"claim":"Extended STAU1 function beyond RNA decay to transcriptional coactivation, showing it bridges TDP-43 to the SAGA complex at a viral promoter and stabilizes HBx protein.","evidence":"TurboID proximity labeling, co-IP, ChIP, and reporter assays in an HBV system","pmids":["35663023"],"confidence":"Medium","gaps":["Generality of STAU1 promoter recruitment to host genes unknown","Single lab"]},{"year":2023,"claim":"Defined a STAU1-mTOR translational axis, showing STAU1 binds the MTOR 5' UTR to boost mTOR translation and impair autophagy, with reduction protective in ALS models.","evidence":"5' UTR binding assays, mTOR-pathway western blots, and STAU1 reduction in ALS mouse models","pmids":["36652469"],"confidence":"Medium","gaps":["Mechanism of 5' UTR-driven translational enhancement not resolved","Single lab"]},{"year":2023,"claim":"Implicated STAU1 in alternative splicing regulation, showing it binds Pparγ2 pre-mRNA to control exon usage and adipocyte differentiation.","evidence":"RIP, PAR-CLIP, and RNA-seq with knockdown/overexpression in 3T3-L1 adipocytes","pmids":["36871938"],"confidence":"Medium","gaps":["Mechanism by which STAU1 influences spliceosome choice unknown","Nuclear versus cytoplasmic site of action not delineated"]},{"year":2024,"claim":"Demonstrated that STAU1 forms dynamic cytoplasmic condensates that physically organize MTOR mRNA translation, mechanistically linking STAU1 condensation to mTOR hyperactivation and autophagy-lysosome dysfunction.","evidence":"Live-cell condensate imaging, in vitro translation assays, in vivo mouse models, and functional rescue by condensate interference","pmids":["38913026"],"confidence":"High","gaps":["Molecular determinants of STAU1 condensate assembly not fully mapped","Single lab"]},{"year":2024,"claim":"Defined disease-relevant 3' UTR stabilization targets, showing STAU1 extends BACE1 and PTEN mRNA half-lives to drive amyloidogenesis/tauopathy and hepatic insulin resistance respectively.","evidence":"RIP, mRNA half-life assays, pathway western blots, and in vivo mouse models","pmids":["38729552","39138413"],"confidence":"Medium","gaps":["What directs STAU1 to stabilize rather than degrade these 3' UTRs not resolved","Single lab per target"]},{"year":2025,"claim":"Resolved the molecular basis of STAU1's decay-versus-stabilization switch, showing glucose-induced DDX50 monomers redirect STAU1 from the UPF1 decay complex into a stabilizing RNP for pro-differentiation mRNAs.","evidence":"Co-IP, CLIP-seq, mRNA stability assays, and in vitro reconstitution of the DDX50-STAU1 complex","pmids":["39764852"],"confidence":"Medium","gaps":["Quantitative partitioning between UPF1 and DDX50 complexes in vivo not defined","Single lab"]},{"year":2025,"claim":"Connected STAU1 abundance to p53-dependent apoptosis, showing STAU1 reduction blunts pro-apoptotic and DNA-damage signaling in neurons and C9orf72-ALS models with baseline STAU1 overabundance.","evidence":"RNAi, transcriptomics, Nutlin-3/etoposide apoptosis assays, and patient fibroblast and C9orf72 mouse models","pmids":["41145462"],"confidence":"Medium","gaps":["Direct link between STAU1 RNA targets and p53 activation not established","Single lab"]},{"year":2026,"claim":"Extended STAU1's SMD and stabilization activities into cancer metastasis, showing trans Alu-directed CDH1 decay promotes metastasis and 3' UTR stabilization of ITGB5 feeds a STAU1-ITGB5-FOXP3 feedback loop.","evidence":"RIP, Alu mutagenesis reporters, ChIP, STAU1/UPF1 knockdown, and xenograft/metastasis models","pmids":["41632098","41796846"],"confidence":"Medium","gaps":["ITGB5/FOXP3 loop lacks reconstitution or mutagenesis validation (Low-confidence)","Tissue-specific selection of decay versus stabilization targets unresolved"]},{"year":2026,"claim":"Established STAU1 as a metabolic regulator of thermogenesis, showing it degrades Ucp1 mRNA via SMD under β3-adrenergic/cAMP-PKA control, with adipose-specific deletion enhancing thermogenesis.","evidence":"RIP, adipose-specific Stau1 knockout mice, metabolic phenotyping, and pharmacological pathway manipulation","pmids":["42242623"],"confidence":"Medium","gaps":["How cAMP-PKA mechanistically lowers STAU1 not defined","Single lab"]},{"year":null,"claim":"It remains unresolved what general molecular logic—partner availability, phosphorylation, condensation, or RNA structure—dictates whether STAU1 degrades, stabilizes, exports, or translationally promotes any given transcript in a physiological context.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model integrating UPF1/DDX50 partitioning, S20 phosphorylation, and condensation","Genome-wide rules for target-fate determination not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[0,1,4,5,12,13,14,15,19,20]},{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[0,19,20]},{"term_id":"GO:0045182","term_label":"translation regulator activity","supporting_discovery_ids":[1,8,9]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,15]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1,8]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0,15,20]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[8,9,11,16]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[2,7,17]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[5]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[6]}],"complexes":["STAU1-UPF1 SMD complex","DDX50-STAU1 ribonucleoprotein","TDP-43/FMRP/STAU1 complex","STAU1 cytoplasmic condensates"],"partners":["UPF1","DDX50","TARDBP","FMR1","TRIM25","MDA5","GIGYF2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O95793","full_name":"Double-stranded RNA-binding protein Staufen homolog 1","aliases":[],"length_aa":577,"mass_kda":63.2,"function":"Binds double-stranded RNA (regardless of the sequence) and tubulin. May play a role in specific positioning of mRNAs at given sites in the cell by cross-linking cytoskeletal and RNA components, and in stimulating their translation at the site (Microbial infection) Plays a role in virus particles production of many viruses including of HIV-1, HERV-K, ebola virus and influenza virus. Acts by interacting with various viral proteins involved in particle budding process","subcellular_location":"Cytoplasm; Rough endoplasmic reticulum","url":"https://www.uniprot.org/uniprotkb/O95793/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/STAU1","classification":"Not Classified","n_dependent_lines":3,"n_total_lines":1208,"dependency_fraction":0.0024834437086092716},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"RPL11","stoichiometry":4.0},{"gene":"RPS16","stoichiometry":4.0},{"gene":"ATG13","stoichiometry":0.2},{"gene":"ATG4B","stoichiometry":0.2},{"gene":"CAPRIN1","stoichiometry":0.2},{"gene":"CAPZB","stoichiometry":0.2},{"gene":"CLTA","stoichiometry":0.2},{"gene":"DDX21","stoichiometry":0.2},{"gene":"DDX6","stoichiometry":0.2},{"gene":"DHX9","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/STAU1","total_profiled":1310},"omim":[{"mim_id":"620839","title":"CHROMOSOME 6 OPEN READING FRAME 132; 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knockdown of any one of the three proteins reduces SIRT1 mRNA and protein and sensitizes cells to apoptosis.\",\n      \"method\": \"Co-immunoprecipitation, RNA immunoprecipitation (RIP), RNA pulldown, siRNA knockdown, microarray\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal RIP and pulldown with functional validation, single lab\",\n      \"pmids\": [\"22584570\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Stau1 negatively regulates myogenic differentiation in C2C12 myoblasts; Stau1 knockdown increases myogenin mRNA and protein levels and promotes spontaneous myogenesis, through a mechanism independent of its co-factor Upf1 (Upf1 knockdown did not affect myogenesis).\",\n      \"method\": \"siRNA knockdown in C2C12 cells, RT-PCR, western blot, myogenin promoter reporter assay, immunofluorescence\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KD with defined cellular phenotype and genetic dissection from Upf1, single lab\",\n      \"pmids\": [\"18422603\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Stau1 binds the 3' UTR of Dvl2 mRNA and stabilizes it in undifferentiated C2C12 myoblasts; Stau1 knockdown shortens the half-life of Dvl2 3' UTR-containing reporter mRNA, and association of Stau1 with Dvl2 3' UTR decreases upon induction of myogenic differentiation, correlating with reduced Dvl2 mRNA levels.\",\n      \"method\": \"RNA immunoprecipitation, mRNA half-life assay (reporter with Dvl2 3' UTR), siRNA knockdown, RT-PCR, western blot\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RIP plus functional mRNA stability assay with defined 3' UTR construct, single lab\",\n      \"pmids\": [\"22166206\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"STAU1 directly binds IBDV genomic double-stranded RNA via its N-terminal moiety (residues 1–468); this binding decreases MDA5 association with viral dsRNA in vitro, attenuating MDA5-dependent IFN-β induction and promoting IBDV replication. A binding-deficient mutant (residues 469–702) failed to suppress IFN-β promoter activity.\",\n      \"method\": \"In vitro binding assay, co-immunoprecipitation, IFN-β promoter reporter assay, siRNA knockdown, overexpression of deletion mutants\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro binding plus mutagenesis plus functional reporter, single lab\",\n      \"pmids\": [\"29979632\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"STAU1 protein levels are downregulated during mitosis by the E3 ubiquitin ligase APC/C; the degradation determinant was mapped to a short FPL-motif (F39PxPxxLxxxxL50) by alanine scanning, and mutation of this motif prevents APC/C-mediated STAU1 degradation. Additionally, TRIM25 (an E3 ubiquitin ligase) was identified by proximity labeling as responsible for degrading STAU1 and MAP4K1 in a FPL-motif-dependent manner.\",\n      \"method\": \"Alanine scanning mutagenesis, cycloheximide chase, proximity labeling (BioID), proteasome inhibitor assays, mass spectrometry\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — mutagenesis defining degradation motif plus proximity labeling identification of E3 ligase, single lab, multiple methods\",\n      \"pmids\": [\"36232890\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Phosphomimicry at STAU1 serine 20 (S20D mutation) impairs STAU1-mediated translational regulation and mRNA decay, triggers apoptosis in cancer cells, and alters proliferation; even the isolated N-terminal 88-amino-acid fragment (RBD2S20D, lacking RNA-binding activity) induces apoptosis by acting in trans on endogenous STAU1 posttranscriptional functions.\",\n      \"method\": \"Site-directed mutagenesis (S20D phosphomimetic), overexpression in cancer cell lines, apoptosis assays, polysome profiling, mRNA stability assays\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — mutagenesis with functional phenotypic readouts, multiple assays, single lab\",\n      \"pmids\": [\"35806349\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Endogenous STAU1 forms dynamic cytoplasmic condensates; these condensates recruit MTOR mRNA at its 5' UTR and promote mTOR translation both in vitro and in vivo. Excessive STAU1 condensate formation leads to mTOR hyperactivation and autophagy-lysosome dysfunction, and interference with condensate formation normalizes mTOR levels and restores autophagic flux.\",\n      \"method\": \"Live-cell imaging of condensates, in vitro translation assay, in vivo mouse models, STAU1 overexpression/knockdown, autophagy flux assays, mTOR pathway western blot\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (live imaging, in vitro translation, in vivo models, functional rescue), single lab with rigorous controls\",\n      \"pmids\": [\"38913026\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"STAU1 overexpression in HEK293 cells increases mTOR translation by directly interacting with the MTOR mRNA 5' UTR, activating downstream mTOR targets and impairing autophagic flux; reducing STAU1 in ALS mouse models normalizes mTOR activity and autophagy-related marker proteins.\",\n      \"method\": \"STAU1 overexpression/knockdown, mTOR 5' UTR binding assay, western blot for mTOR pathway components, mouse model intervention\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct 5' UTR binding assay plus in vivo validation, single lab\",\n      \"pmids\": [\"36652469\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"STAU1 indirectly binds the HBV core promoter (CP) via TARDBP (TDP-43) and recruits the SAGA transcriptional coactivator complex to upregulate CP activity; STAU1 also binds HBx protein and stabilizes it in a ubiquitin-independent manner.\",\n      \"method\": \"TurboID-based proximity labeling, co-immunoprecipitation, ChIP, reporter assays, siRNA knockdown\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — proximity labeling plus co-IP plus reporter assays, single lab\",\n      \"pmids\": [\"35663023\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"STAU1 silencing in alveolar rhabdomyosarcoma (ARMS) cells reduces autophagy by destabilizing BECN1 and ATG16L1 mRNAs, and indirectly inhibits JNK signaling via increased DUSP8 expression; pharmacological JNK activation or DUSP8 silencing restores autophagy in STAU1-depleted ARMS cells. In contrast, in non-transformed skeletal muscle cells, STAU1 downregulation activates autophagy in an mTOR-dependent manner.\",\n      \"method\": \"siRNA knockdown, mRNA stability assay, western blot, JNK pathway pharmacological rescue, STAU1-transgenic mouse skeletal muscle analysis\",\n      \"journal\": \"Cellular oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — knockdown with defined molecular mechanism and pharmacological rescue, single lab, multiple cell types\",\n      \"pmids\": [\"33899158\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"STAU1 stabilizes BACE1 mRNA by binding to its 3' UTR, extending BACE1 mRNA half-life; STAU1 also enhances GADD45B expression, activating P38 MAPK signaling to promote Tau phosphorylation at Ser396 and Thr181, thereby promoting both amyloidogenesis and tauopathy.\",\n      \"method\": \"STAU1 knockdown/overexpression, mRNA half-life assay, RIP for 3' UTR binding, transcriptome analysis, western blot for P38 MAPK pathway\",\n      \"journal\": \"Experimental neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RIP plus mRNA stability plus pathway validation, single lab\",\n      \"pmids\": [\"38729552\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GIGYF2 upregulates STAU1, which then stabilizes PTEN mRNA by binding to its 3' UTR, leading to PI3K/AKT pathway inactivation and hepatic insulin resistance; STAU1 silencing prevents GIGYF2-induced PTEN upregulation and restores AKT signaling.\",\n      \"method\": \"RNA immunoprecipitation (RIP), siRNA knockdown, overexpression, western blot, in vivo high-fat diet mouse model\",\n      \"journal\": \"Molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RIP demonstrating 3' UTR binding with in vivo validation, single lab\",\n      \"pmids\": [\"39138413\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"STAU1 regulates alternative splicing of Pparγ2 pre-mRNA in 3T3-L1 adipocytes, specifically affecting the splicing of exon E1, as demonstrated by RIP and PAR-CLIP showing STAU1 binding to Pparγ2 pre-mRNA; knockdown/overexpression of STAU1 alters adipocyte differentiation and lipid metabolism gene splicing patterns.\",\n      \"method\": \"RNA immunoprecipitation (RIP), PAR-CLIP, sucrose density gradient centrifugation, RNA-seq for alternative splicing, siRNA knockdown\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular and cell biology of lipids\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RIP plus PAR-CLIP plus RNA-seq with functional validation, single lab\",\n      \"pmids\": [\"36871938\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"DDX50 monomers (formed upon glucose binding) bind STAU1 and redirect it from an RNA-decay-promoting complex with UPF1 to a DDX50-STAU1 ribonucleoprotein complex that stabilizes pro-differentiation mRNAs including JUN, OVOL1, CEBPB, PRDM1, and TINCR, reversing STAU1's canonical SMD role.\",\n      \"method\": \"Co-immunoprecipitation, RNA pulldown, CLIP-seq, mRNA stability assays, genetic knockdown, in vitro reconstitution of DDX50-STAU1 complex\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus CLIP-seq plus mRNA stability assays, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"39764852\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"tRF-3019A competitively binds STAU1 protein, displacing BECN1 mRNA from STAU1, thereby enhancing BECN1 mRNA stability and expression, which promotes autophagy and malignant progression in colon cancer.\",\n      \"method\": \"RNA pulldown, RNA immunoprecipitation (RIP), western blot, GFP-LC3B autophagy assay, xenograft tumor model\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, pulldown and RIP without reconstitution or mutagenesis validation\",\n      \"pmids\": [\"40268078\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"STAU1 reduction inhibits p53-mediated apoptosis and DNA damage responses in multiple cell types (iPSC-derived neurons, mouse cortical neurons, SH-SY5Y cells, fibroblasts); in C9orf72-expanded patient fibroblasts and mouse ALS models with baseline STAU1 overabundance, STAU1 reduction prevents p53-driven pro-apoptotic signaling.\",\n      \"method\": \"RNAi knockdown, transcriptomic analysis, apoptosis assays (Nutlin-3 and etoposide treatment), p53 pathway western blot, patient-derived fibroblasts, C9orf72 mouse model\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — transcriptomic plus functional rescue across multiple cell types and in vivo model, single lab\",\n      \"pmids\": [\"41145462\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"STAU1 directly binds the 3' UTR of ITGB5 mRNA to stabilize it; ITGB5 upregulation increases FOXP3 phosphorylation at serine 418, which activates FOXP3 binding to the STAU1 promoter, creating a STAU1-ITGB5-FOXP3 positive feedback loop driving CRC metastasis.\",\n      \"method\": \"RIP, RNA stability assay, ChIP, siRNA knockdown, overexpression, in vitro and in vivo metastasis assays\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, RIP and ChIP with functional assays but no reconstitution or mutagenesis\",\n      \"pmids\": [\"41796846\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"STAU1 binds the 3' UTR of Ucp1 mRNA and promotes its degradation via SMD; adipose-specific STAU1 deletion upregulates UCP1 protein and enhances thermogenesis in mice. The β3 adrenergic receptor/cAMP-PKA pathway modulates STAU1 activity, with cAMP-PKA inhibition downregulating STAU1.\",\n      \"method\": \"RIP for 3' UTR binding, adipose-specific Stau1 knockout mice, metabolic phenotyping, western blot, pharmacological pathway manipulation\",\n      \"journal\": \"Metabolism: clinical and experimental\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RIP plus tissue-specific knockout with clear molecular and metabolic phenotype, single lab\",\n      \"pmids\": [\"42242623\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"An Alu element in lnc-APUE base-pairs with the Alu element in the 3' UTR of CDH1 mRNA, triggering CDH1 mRNA decay via the STAU1-UPF1 (SMD) pathway; silencing STAU1 or UPF1 abrogates lnc-APUE-mediated CDH1 decay and tumor metastasis promotion.\",\n      \"method\": \"siRNA knockdown of STAU1/UPF1, Alu element deletion/mutation reporter assays, xenograft mouse model, RIP\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis (STAU1/UPF1 knockdown rescue), Alu mutagenesis, in vivo validation, single lab\",\n      \"pmids\": [\"41632098\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"STAU1 is a double-stranded RNA-binding protein that functions as a central post-transcriptional regulator: it mediates Staufen-mediated mRNA decay (SMD) by binding dsRNA structures in 3' UTRs—including those formed by Alu element base-pairing with lncRNAs—and recruiting UPF1, but can be redirected by DDX50 to stabilize pro-differentiation mRNAs; it also promotes mRNA stability (e.g., BACE1, PTEN, Dvl2, Ucp1) by 3' UTR binding, enhances nuclear export and translation by blocking PKR binding to 3' UTR inverted-repeat Alus, promotes mTOR translation via 5' UTR binding leading to autophagy dysfunction when overabundant, undergoes APC/C- and TRIM25-mediated proteasomal degradation via an FPL-motif, is functionally regulated by phosphorylation at serine 20, and participates in complexes with TDP-43/FMRP and DDX50 that collectively determine whether bound mRNAs are stabilized or degraded.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"STAU1 is a double-stranded RNA-binding protein that acts as a bidirectional post-transcriptional regulator, determining whether bound mRNAs are degraded or stabilized depending on its partner complexes [#0, #15]. In its canonical decay role, STAU1 binds dsRNA structures in 3' UTRs—including those formed in trans by imperfect base-pairing between an Alu element in a target 3' UTR and a complementary Alu in a cytoplasmic lncRNA—and recruits UPF1 to trigger Staufen-mediated mRNA decay (SMD) [#0, #20]. This SMD activity destabilizes targets such as CDH1 and Ucp1, with the latter linking STAU1 to adipose thermogenesis under β3-adrenergic/cAMP-PKA control [#19, #20]. Conversely, STAU1 stabilizes numerous transcripts by 3' UTR binding—BACE1, PTEN, and Dvl2 among them—and can be redirected away from the UPF1 decay complex into a DDX50-STAU1 complex that stabilizes pro-differentiation mRNAs, reversing its SMD function [#4, #12, #13, #15]. STAU1 binding to inverted-repeat Alu elements additionally augments nuclear export of those mRNAs and blocks PKR access to the dsRNA, preventing PKR-mediated eIF2α phosphorylation and global translational repression [#1]. Through dynamic cytoplasmic condensates STAU1 recruits MTOR mRNA at its 5' UTR to promote mTOR translation, such that STAU1 overabundance drives mTOR hyperactivation and autophagy-lysosome dysfunction [#8, #9]. STAU1 abundance is itself controlled by APC/C- and TRIM25-mediated proteasomal degradation via an FPL-motif and is functionally modulated by phosphorylation at serine 20 [#6, #7]. STAU1 overabundance promotes p53-driven apoptosis in neuronal disease models including C9orf72-expanded ALS, where its reduction is protective [#17].\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Established that Staufen has an mRNA-regulatory role in cell-fate decisions independent of its known decay cofactor, showing it is not solely an SMD effector.\",\n      \"evidence\": \"siRNA knockdown in C2C12 myoblasts with myogenin reporter and genetic dissection from Upf1\",\n      \"pmids\": [\"18422603\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct mRNA targets mediating the myogenic phenotype not defined in this study\", \"Upf1-independent molecular mechanism not resolved\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Revealed that STAU1 decay sites can be assembled in trans by Alu-Alu base-pairing between a target 3' UTR and a cytoplasmic lncRNA, explaining how SMD targets are specified without a perfect cis stem-loop.\",\n      \"evidence\": \"Reciprocal RNA co-IP, reporter assays, and siRNA knockdown identifying 1/2-sbsRNA Alu pairing\",\n      \"pmids\": [\"21307942\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Genome-wide scope of trans-acting lncRNA-directed SMD not enumerated\", \"Structural basis of imperfect duplex recognition not defined\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstrated that STAU1 can stabilize rather than degrade a 3' UTR-bound transcript (Dvl2), and that this binding is developmentally regulated, foreshadowing STAU1's dual decay/stabilization output.\",\n      \"evidence\": \"RIP and reporter mRNA half-life assays in differentiating C2C12 cells\",\n      \"pmids\": [\"22166206\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"What switches STAU1 between stabilizing and decay modes not addressed\", \"Single 3' UTR construct\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Placed STAU1 in a multiprotein RNP with TDP-43 and FMRP that stabilizes a specific target (SIRT1), establishing partner-dependent stabilization with an apoptosis-relevant readout.\",\n      \"evidence\": \"Co-IP, reciprocal RIP, RNA pulldown, and knockdown with apoptosis assays\",\n      \"pmids\": [\"22584570\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Stoichiometry and assembly order of the TDP-43/FMRP/STAU1 complex unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Showed STAU1 binding to 3' UTR inverted-repeat Alus serves a dual gatekeeping function—promoting nuclear export and excluding PKR to prevent eIF2α-mediated translational shutdown.\",\n      \"evidence\": \"Nuclear/cytoplasmic fractionation, reporter assays, co-IP, and eIF2α phosphorylation assays\",\n      \"pmids\": [\"23824540\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Competition kinetics between STAU1 and PKR for IRAlus not quantified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined STAU1 as a direct dsRNA-binding antagonist of innate immune sensing, mapping the activity to its N-terminal moiety that competes with MDA5 for viral dsRNA.\",\n      \"evidence\": \"In vitro binding, deletion-mutant overexpression, and IFN-β promoter reporter assays in an IBDV system\",\n      \"pmids\": [\"29979632\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relevance to mammalian antiviral responses not established\", \"Residues mediating MDA5 competition not pinpointed\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified how STAU1 abundance is set, mapping an FPL degron targeted by APC/C during mitosis and by TRIM25, providing a degradative control point on STAU1 activity.\",\n      \"evidence\": \"Alanine-scanning mutagenesis, cycloheximide chase, proximity labeling, and proteasome inhibition\",\n      \"pmids\": [\"36232890\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological triggers for TRIM25-mediated turnover unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Established phosphorylation at serine 20 as a functional switch on STAU1's post-transcriptional output, with a phosphomimetic N-terminal fragment acting in trans to induce apoptosis.\",\n      \"evidence\": \"S20D phosphomimetic mutagenesis, polysome profiling, mRNA stability and apoptosis assays in cancer cells\",\n      \"pmids\": [\"35806349\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Kinase responsible for S20 phosphorylation not identified\", \"Mechanism of dominant-negative trans action of the RBD2 fragment unresolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Extended STAU1 function beyond RNA decay to transcriptional coactivation, showing it bridges TDP-43 to the SAGA complex at a viral promoter and stabilizes HBx protein.\",\n      \"evidence\": \"TurboID proximity labeling, co-IP, ChIP, and reporter assays in an HBV system\",\n      \"pmids\": [\"35663023\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Generality of STAU1 promoter recruitment to host genes unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined a STAU1-mTOR translational axis, showing STAU1 binds the MTOR 5' UTR to boost mTOR translation and impair autophagy, with reduction protective in ALS models.\",\n      \"evidence\": \"5' UTR binding assays, mTOR-pathway western blots, and STAU1 reduction in ALS mouse models\",\n      \"pmids\": [\"36652469\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of 5' UTR-driven translational enhancement not resolved\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Implicated STAU1 in alternative splicing regulation, showing it binds Pparγ2 pre-mRNA to control exon usage and adipocyte differentiation.\",\n      \"evidence\": \"RIP, PAR-CLIP, and RNA-seq with knockdown/overexpression in 3T3-L1 adipocytes\",\n      \"pmids\": [\"36871938\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which STAU1 influences spliceosome choice unknown\", \"Nuclear versus cytoplasmic site of action not delineated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrated that STAU1 forms dynamic cytoplasmic condensates that physically organize MTOR mRNA translation, mechanistically linking STAU1 condensation to mTOR hyperactivation and autophagy-lysosome dysfunction.\",\n      \"evidence\": \"Live-cell condensate imaging, in vitro translation assays, in vivo mouse models, and functional rescue by condensate interference\",\n      \"pmids\": [\"38913026\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular determinants of STAU1 condensate assembly not fully mapped\", \"Single lab\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined disease-relevant 3' UTR stabilization targets, showing STAU1 extends BACE1 and PTEN mRNA half-lives to drive amyloidogenesis/tauopathy and hepatic insulin resistance respectively.\",\n      \"evidence\": \"RIP, mRNA half-life assays, pathway western blots, and in vivo mouse models\",\n      \"pmids\": [\"38729552\", \"39138413\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"What directs STAU1 to stabilize rather than degrade these 3' UTRs not resolved\", \"Single lab per target\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved the molecular basis of STAU1's decay-versus-stabilization switch, showing glucose-induced DDX50 monomers redirect STAU1 from the UPF1 decay complex into a stabilizing RNP for pro-differentiation mRNAs.\",\n      \"evidence\": \"Co-IP, CLIP-seq, mRNA stability assays, and in vitro reconstitution of the DDX50-STAU1 complex\",\n      \"pmids\": [\"39764852\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Quantitative partitioning between UPF1 and DDX50 complexes in vivo not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected STAU1 abundance to p53-dependent apoptosis, showing STAU1 reduction blunts pro-apoptotic and DNA-damage signaling in neurons and C9orf72-ALS models with baseline STAU1 overabundance.\",\n      \"evidence\": \"RNAi, transcriptomics, Nutlin-3/etoposide apoptosis assays, and patient fibroblast and C9orf72 mouse models\",\n      \"pmids\": [\"41145462\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct link between STAU1 RNA targets and p53 activation not established\", \"Single lab\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Extended STAU1's SMD and stabilization activities into cancer metastasis, showing trans Alu-directed CDH1 decay promotes metastasis and 3' UTR stabilization of ITGB5 feeds a STAU1-ITGB5-FOXP3 feedback loop.\",\n      \"evidence\": \"RIP, Alu mutagenesis reporters, ChIP, STAU1/UPF1 knockdown, and xenograft/metastasis models\",\n      \"pmids\": [\"41632098\", \"41796846\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"ITGB5/FOXP3 loop lacks reconstitution or mutagenesis validation (Low-confidence)\", \"Tissue-specific selection of decay versus stabilization targets unresolved\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Established STAU1 as a metabolic regulator of thermogenesis, showing it degrades Ucp1 mRNA via SMD under β3-adrenergic/cAMP-PKA control, with adipose-specific deletion enhancing thermogenesis.\",\n      \"evidence\": \"RIP, adipose-specific Stau1 knockout mice, metabolic phenotyping, and pharmacological pathway manipulation\",\n      \"pmids\": [\"42242623\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How cAMP-PKA mechanistically lowers STAU1 not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved what general molecular logic—partner availability, phosphorylation, condensation, or RNA structure—dictates whether STAU1 degrades, stabilizes, exports, or translationally promotes any given transcript in a physiological context.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model integrating UPF1/DDX50 partitioning, S20 phosphorylation, and condensation\", \"Genome-wide rules for target-fate determination not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [0, 1, 4, 5, 12, 13, 14, 15, 19, 20]},\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [0, 19, 20]},\n      {\"term_id\": \"GO:0045182\", \"supporting_discovery_ids\": [1, 8, 9]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 15]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0, 15, 20]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [8, 9, 11, 16]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [2, 7, 17]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"complexes\": [\n      \"STAU1-UPF1 SMD complex\",\n      \"DDX50-STAU1 ribonucleoprotein\",\n      \"TDP-43/FMRP/STAU1 complex\",\n      \"STAU1 cytoplasmic condensates\"\n    ],\n    \"partners\": [\n      \"UPF1\",\n      \"DDX50\",\n      \"TARDBP\",\n      \"FMR1\",\n      \"TRIM25\",\n      \"MDA5\",\n      \"GIGYF2\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}