{"gene":"PAN3","run_date":"2026-06-10T05:19:53","timeline":{"discoveries":[{"year":1996,"finding":"Pan3p (76-kDa subunit) is required for PAN (poly(A) nuclease) enzymatic activity in yeast; deletion of PAN3 abolishes PAN activity in cell extracts, immunodepletion of Pan3p from purified PAN fractions eliminates activity, and Pan2p and Pan3p physically interact by coimmunoprecipitation and two-hybrid assay. Both subunits are required for in vivo poly(A) tail shortening.","method":"Genetic deletion, enzymatic activity assay in yeast extracts, immunodepletion, coimmunoprecipitation, two-hybrid assay, in vivo poly(A) tail length analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (deletion, biochemical activity assay, immunodepletion, Co-IP, two-hybrid, in vivo poly(A) measurement) in founding mechanistic paper","pmids":["8816488"],"is_preprint":false},{"year":2002,"finding":"The Dun1 kinase forkhead-associated domain interacts with the Pan3 subunit of the poly(A)-nuclease complex; dun1/pan2 and dun1/pan3 double mutants are hypersensitive to replication stress, and Dun1 and Pan2-Pan3 cooperate to regulate posttranscriptional control of the RAD5 DNA repair gene, which is specifically up-regulated in dun1/pan2 double mutants.","method":"Yeast two-hybrid (Dun1 FHA domain–Pan3 interaction), genetic double-mutant phenotypic analysis, replication stress sensitivity assay, gene expression analysis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — two-hybrid interaction plus genetic epistasis with defined phenotypic readout, single lab","pmids":["11953437"],"is_preprint":false},{"year":2012,"finding":"C. elegans AIN-1 (GW182 homolog) interacts with PAN3 (as well as PAB-1 and NOT1/NOT2), demonstrating that GW182-family recruitment of the PAN2-PAN3 deadenylase complex is evolutionarily conserved in C. elegans miRNA-mediated silencing.","method":"Coimmunoprecipitation, directed protein interaction assays in C. elegans and Drosophila cell contexts","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP-based interaction, replicated across species contexts in single study","pmids":["22402495"],"is_preprint":false},{"year":2013,"finding":"Crystal structure of PAN3 reveals it forms asymmetric homodimers via a coiled coil linking an N-terminal pseudokinase to a C-terminal knob domain. The knob domain contains the binding surface for PAN2. A tryptophan-binding pocket at the dimer interface mediates binding to TNRC6C (GW182), enabling PAN2-PAN3 recruitment to miRNA targets. PAN3 pseudokinase binds ATP, and this ATP-binding function is required for mRNA deadenylation in vivo.","method":"X-ray crystallography, in vivo deadenylation assay, mutagenesis of binding surfaces, cell-based interaction assays with TNRC6C","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure combined with mutagenesis and in vivo functional validation in single rigorous study","pmids":["23932717"],"is_preprint":false},{"year":2014,"finding":"Crystal structure of the Pan2-Pan3 core complex (~200 kDa) shows a 1:2 (Pan2:Pan3) stoichiometry imposed by the asymmetric Pan3 homodimer. An extended region of Pan2 wraps around Pan3 as the major anchoring point. A Pan2 module formed by the pseudo-ubiquitin-hydrolase and RNase domains latches onto the Pan3 pseudokinase, orienting the deadenylase active site toward the A-binding site of Pan3. Recombinant yeast Pan2-Pan3 can deadenylate RNA in vitro without Pab1.","method":"X-ray crystallography of recombinant complex, in vitro deadenylation assay","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with in vitro reconstitution, multiple orthogonal approaches in single study","pmids":["24880344"],"is_preprint":false},{"year":2014,"finding":"Pan3 directly binds poly(A) RNA through two regions: an N-terminal zinc finger that binds poly(A) specifically, and its pseudokinase/C-terminal domain. Isolated Pan2 cannot bind RNA. Pan3 binds the linker region of Pan2 connecting its WD40 domain to the exonuclease domain with 2:1 (Pan3:Pan2) stoichiometry. Crystal structure of the Pan2 linker–Pan3 homodimer complex shows how Pan3 asymmetry creates a high-affinity interaction, enabling Pan3 to supply Pan2 with poly(A) substrate.","method":"RNA-binding assays, crystal structure of Pan2 linker–Pan3 complex, stoichiometry determination, in vitro deadenylation assays","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus direct RNA-binding biochemistry and stoichiometry determination in single rigorous study","pmids":["24872509"],"is_preprint":false},{"year":2014,"finding":"Arsenite-induced oxidative stress inhibits mRNA deadenylation through proteolytic degradation of Pan3 (and Tob). siRNA knockdown of Pan3 alone recapitulates global poly(A) tail stabilization seen during arsenite stress, establishing Pan3 as an essential mediator of deadenylase recruitment under stress conditions.","method":"Arsenite treatment, siRNA knockdown, poly(A) tail length analysis, protein degradation assays","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — siRNA knockdown with defined molecular phenotype (poly(A) tail stabilization), single lab","pmids":["25446091"],"is_preprint":false},{"year":2017,"finding":"Two human PAN3 isoforms (Pan3S and Pan3L) have opposing activities: Pan3S interacts more strongly with PABP and enhances Pan2 deadenylase activity, while Pan3L suppresses Pan2 activity. Knockdown of individual isoforms has opposing effects on global poly(A) tail length, P-body formation, and mRNA decay pathways, revealing that the two isoforms coordinate the first phase of biphasic deadenylation.","method":"Isoform-specific knockdown, global poly(A) tail profiling, transcriptome-wide mRNA stability analysis, PABP interaction assays, P-body imaging","journal":"RNA (New York, N.Y.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (knockdown, transcriptome-wide profiling, binding assays, imaging) in single lab study","pmids":["28559491"],"is_preprint":false},{"year":2019,"finding":"Cryo-EM structure of Pan2-Pan3 in complex with a poly(A) RNP (90 adenosines + three Pab1 protomers) shows that Pan2-Pan3 recognizes the oligomerization interfaces of Pab1 via conserved features of the deadenylase and threads the poly(A) RNA substrate into the nuclease active site. Pan2-Pan3 associates with and degrades poly(A) RNPs containing two or more Pab1 molecules. This reveals how Pab1 oligomers act as rulers for poly(A) tail length.","method":"Cryo-EM structure determination, in vitro reconstitution with recombinant proteins, deadenylation activity assays","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure combined with in vitro reconstitution and activity assays in single rigorous study","pmids":["31104843"],"is_preprint":false},{"year":2021,"finding":"Pan2 and Pan3 are phosphorylated when yeast are switched to non-fermentable carbon sources (glycerol-lactate), suggesting their activities are regulated by phosphorylation in response to carbon source changes. The Pan2-Pan3 complex cooperates with Ccr4-Not for growth on non-fermentable carbon sources.","method":"Genetic deletion analysis, growth assays on non-fermentable carbon media, multicopy suppressor screen, phosphorylation detection","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — phosphorylation detected but writer/eraser not identified; single lab, single method for phosphorylation claim","pmids":["34280615"],"is_preprint":false},{"year":2025,"finding":"Cryo-EM structures of human PAN2-PAN3 bound to poly(A)-PABPC1 ribonucleoproteins reveal a longer substrate-binding path in the human deadenylase compared to the fungal ortholog, providing structural basis for the co-evolution of deadenylase properties with the longer poly(A) tails characteristic of mammalian mRNAs. Human PAN2-PAN3 shows greater deadenylation activity on long poly(A)-PABPC1 substrates in vitro.","method":"Cryo-EM structure determination, in vitro deadenylation assays with poly(A) RNAs up to 240 nt, comparative structural analysis","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cryo-EM structure with in vitro activity assays, single lab but orthogonal methods","pmids":["41275497"],"is_preprint":false},{"year":2025,"finding":"PAN2-PAN3 can be recruited to specific mRNAs via RNA-binding protein (RBP) adaptors, including MEX3, YTHDF, and ZFP36 proteins, as demonstrated by biochemical reconstitution. In cells, a diverse range of RNA adaptors interact with both PAN2-PAN3 and CCR4-NOT, indicating PAN2-PAN3 contributes to transcript-specific mRNA degradation beyond general PABP-dependent recruitment.","method":"Biochemical reconstitution, affinity pulldown/interaction assays in cells","journal":"bioRxiv (preprint)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — biochemical reconstitution plus cell-based interaction assays, preprint not yet peer-reviewed","pmids":["bio_10.1101_2025.09.27.678968"],"is_preprint":true}],"current_model":"PAN3 is an essential non-catalytic subunit of the conserved eukaryotic PAN2-PAN3 deadenylase complex that functions as an asymmetric homodimer: it directly binds poly(A) RNA via an N-terminal zinc finger, recruits the PAN2 exonuclease (in a 2:1 PAN3:PAN2 stoichiometry) through contacts between its knob domain and a Pan2 linker region, and orients the PAN2 nuclease active site toward substrate; the complex specifically recognizes poly(A)-PABP oligomeric ribonucleoproteins to catalyze the initial, length-sensitive phase of cytoplasmic deadenylation, and is additionally recruited to miRNA-target mRNAs via a tryptophan-binding pocket in its pseudokinase dimer interface that engages GW182/TNRC6 proteins, and to other specific transcripts via RNA-binding protein adaptors such as MEX3, YTHDF, and ZFP36."},"narrative":{"mechanistic_narrative":"PAN3 is an essential, non-catalytic subunit of the conserved eukaryotic PAN2-PAN3 deadenylase that drives the initial, length-sensitive phase of cytoplasmic poly(A) tail shortening [PMID:8816488, PMID:31104843]. Although required for poly(A) nuclease activity in vivo, PAN3 itself is catalytically inert; it functions as an asymmetric homodimer built from an N-terminal pseudokinase and a C-terminal knob domain joined by a coiled coil, with the knob providing the binding surface for the PAN2 exonuclease [PMID:23932717]. PAN3 supplies substrate and architecture to the complex: it binds poly(A) RNA directly through an N-terminal zinc finger and its pseudokinase domain, engages a PAN2 linker region with 2:1 (PAN3:PAN2) stoichiometry, and orients the PAN2 nuclease active site toward the poly(A) substrate [PMID:24880344, PMID:24872509]. The reconstituted complex recognizes poly(A)-PABP oligomeric ribonucleoproteins, degrading tails decorated with two or more PABP/Pab1 protomers so that PABP oligomers act as molecular rulers for tail length [PMID:31104843], a substrate-binding path that has co-evolved with the longer poly(A) tails of mammalian mRNAs [PMID:41275497]. Beyond bulk PABP-dependent deadenylation, PAN3 confers transcript specificity: a tryptophan-binding pocket at its pseudokinase dimer interface engages GW182/TNRC6 proteins to recruit the complex to miRNA targets [PMID:22402495, PMID:23932717], and additional RNA-binding adaptors such as MEX3, YTHDF, and ZFP36 direct it to specific transcripts [PMID:bio_10.1101_2025.09.27.678968]. PAN3 is also a regulatory node, mediating deadenylase recruitment under oxidative stress, where its proteolytic degradation stabilizes poly(A) tails [PMID:25446091], and two human isoforms exert opposing effects on PAN2 activity and global tail length [PMID:28559491].","teleology":[{"year":1996,"claim":"Established that PAN3 is a required subunit of the poly(A) nuclease, answering whether deadenylase activity depends on more than the catalytic subunit.","evidence":"Genetic deletion, immunodepletion, Co-IP, two-hybrid, and in vivo poly(A) measurement in yeast","pmids":["8816488"],"confidence":"High","gaps":["Did not define which PAN3 region contacts PAN2","No structural basis for how PAN3 enables catalysis","Catalytic versus non-catalytic role of PAN3 not resolved"]},{"year":2002,"claim":"Linked Pan2-Pan3 to a stress-response pathway, showing the deadenylase participates in post-transcriptional control of a DNA repair transcript.","evidence":"Yeast two-hybrid (Dun1 FHA-Pan3) plus genetic epistasis and gene-expression analysis under replication stress","pmids":["11953437"],"confidence":"Medium","gaps":["Direct deadenylation of RAD5 mRNA not demonstrated biochemically","Whether Dun1 phosphorylates Pan3 unknown","Single lab"]},{"year":2012,"claim":"Showed GW182-family recruitment of PAN2-PAN3 in miRNA silencing is evolutionarily conserved, generalizing the targeting mechanism beyond a single species.","evidence":"Co-IP and directed interaction assays of C. elegans AIN-1 with PAN3 in worm/fly contexts","pmids":["22402495"],"confidence":"Medium","gaps":["Co-IP without structural mapping of the interface","Functional consequence for specific miRNA targets not quantified"]},{"year":2013,"claim":"Defined PAN3 domain architecture and the molecular basis of miRNA-target recruitment, explaining how a pseudokinase scaffold engages GW182.","evidence":"X-ray crystallography with mutagenesis and in vivo deadenylation and TNRC6C interaction assays","pmids":["23932717"],"confidence":"High","gaps":["Why ATP binding is needed for deadenylation not mechanistically resolved","Did not capture the PAN2-bound complex"]},{"year":2014,"claim":"Resolved the assembled PAN2-PAN3 core and how PAN3 asymmetry imposes 2:1 stoichiometry, orients the nuclease, and supplies poly(A) substrate via its zinc finger.","evidence":"Crystal structures of the Pan2-Pan3 core and Pan2 linker-Pan3 complex with RNA-binding biochemistry and in vitro deadenylation","pmids":["24880344","24872509"],"confidence":"High","gaps":["Did not show how the complex reads poly(A) tail length","Role of PABP in substrate engagement not yet structural"]},{"year":2014,"claim":"Identified PAN3 as a stress-responsive regulatory node whose degradation stabilizes poly(A) tails, connecting deadenylase recruitment to oxidative stress.","evidence":"Arsenite treatment, siRNA knockdown, and poly(A) tail length and protein-degradation assays","pmids":["25446091"],"confidence":"Medium","gaps":["Protease responsible for PAN3 degradation not identified","Single lab"]},{"year":2017,"claim":"Showed two human PAN3 isoforms exert opposing control over PAN2 activity and global tail length, revealing isoform-level tuning of the first deadenylation phase.","evidence":"Isoform-specific knockdown, transcriptome-wide poly(A) and stability profiling, PABP-interaction and P-body imaging","pmids":["28559491"],"confidence":"Medium","gaps":["Structural basis for opposing isoform activities unknown","How isoform ratio is set physiologically unclear"]},{"year":2019,"claim":"Provided the structural mechanism for length-sensitive deadenylation, showing PABP/Pab1 oligomers serve as rulers recognized by the complex.","evidence":"Cryo-EM of Pan2-Pan3 bound to a poly(A)-Pab1 RNP with in vitro reconstitution and activity assays","pmids":["31104843"],"confidence":"High","gaps":["How the complex transitions from initial to processive trimming not fully defined","Cross-talk with Ccr4-Not at the same substrate unresolved"]},{"year":2021,"claim":"Suggested metabolic regulation of the deadenylase, detecting Pan2/Pan3 phosphorylation upon carbon-source shift and cooperation with Ccr4-Not.","evidence":"Genetic deletion, growth assays on non-fermentable media, suppressor screen, and phosphorylation detection in yeast","pmids":["34280615"],"confidence":"Low","gaps":["Kinase/phosphatase acting on Pan3 not identified","Functional consequence of phosphorylation not demonstrated","Single lab, single method for phospho-claim"]},{"year":2025,"claim":"Demonstrated co-evolution of human deadenylase substrate-binding architecture with longer mammalian poly(A) tails.","evidence":"Cryo-EM of human PAN2-PAN3 with poly(A)-PABPC1 RNPs and comparative in vitro deadenylation on long substrates","pmids":["41275497"],"confidence":"High","gaps":["In-cell relevance of the longer substrate path not tested","Regulation of human-specific features unknown"]},{"year":2025,"claim":"Expanded targeting logic beyond PABP, showing diverse RBP adaptors recruit PAN2-PAN3 for transcript-specific decay.","evidence":"Biochemical reconstitution with MEX3/YTHDF/ZFP36 and cell-based interaction assays (preprint)","pmids":["bio_10.1101_2025.09.27.678968"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Which PAN3 surfaces engage each adaptor not mapped","Transcript-level decay consequences not fully quantified"]},{"year":null,"claim":"How PAN3 phosphorylation, isoform balance, and competing adaptor inputs are integrated to control deadenylase activity and target selection in vivo remains open.","evidence":"","pmids":[],"confidence":"Low","gaps":["No identified PAN3 kinase/phosphatase","Mechanism coordinating PABP-dependent versus adaptor-dependent recruitment unknown","In-cell dynamics of isoform-specific regulation undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[5,8]},{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[3]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[3,5]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[7]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[7]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0,8]}],"complexes":["PAN2-PAN3 deadenylase"],"partners":["PAN2","PABPC1","TNRC6C","AIN-1","MEX3","YTHDF","ZFP36","DUN1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q58A45","full_name":"PAN2-PAN3 deadenylation complex subunit PAN3","aliases":["PAB1P-dependent poly(A)-specific ribonuclease","Poly(A)-nuclease deadenylation complex subunit 3","PAN deadenylation complex subunit 3"],"length_aa":887,"mass_kda":95.6,"function":"Regulatory subunit of the poly(A)-nuclease (PAN) deadenylation complex, one of two cytoplasmic mRNA deadenylases involved in general and miRNA-mediated mRNA turnover. PAN specifically shortens poly(A) tails of RNA and the activity is stimulated by poly(A)-binding protein (PABP). PAN deadenylation is followed by rapid degradation of the shortened mRNA tails by the CCR4-NOT complex. Deadenylated mRNAs are then degraded by two alternative mechanisms, namely exosome-mediated 3'-5' exonucleolytic degradation, or deadenylation-dependent mRNA decapping and subsequent 5'-3' exonucleolytic degradation by XRN1. PAN3 acts as a regulator for PAN activity, recruiting the catalytic subunit PAN2 to mRNA via its interaction with RNA and PABP, and to miRNA targets via its interaction with GW182 family proteins Decreases PAN2-mediated deadenylation, possibly by preventing progression into the second CCR4-NOT mediated stage of biphasic deadenylation. Has a significant effect on mRNA stability, generally stabilizing a subset of the transcriptome. Stabilizes mRNAs degraded by the AU-rich element (ARE)-mediated mRNA decay pathway but promotes degradation of mRNAs by the microRNA-mediated pathway (PubMed:28559491). Its activity influences mRNP remodeling, specifically reducing formation of a subset of P-bodies containing GW220, an isoform of TNRC6A (PubMed:28559491) Enhances PAN2 deadenylase activity and has an extensive effect on mRNA stability, generally enhancing mRNA decay across the transcriptome by multiple pathways, including the AU-rich element (ARE)-mediated pathway, microRNA-mediated pathway and the nonsense-mediated pathway (NMD) (PubMed:28559491). Its activity is required for efficient P-body formation (PubMed:28559491). May be involved in regulating mRNAs of genes involved in cell cycle progression and cell proliferation (PubMed:28559491)","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q58A45/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PAN3","classification":"Not Classified","n_dependent_lines":6,"n_total_lines":1208,"dependency_fraction":0.004966887417218543},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DDX6","stoichiometry":0.2},{"gene":"GSPT1","stoichiometry":0.2},{"gene":"PABPC4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/PAN3","total_profiled":1310},"omim":[{"mim_id":"617448","title":"PABP-DEPENDENT POLY(A) NUCLEASE 3; PAN3","url":"https://www.omim.org/entry/617448"},{"mim_id":"617447","title":"PABP-DEPENDENT POLY(A) NUCLEASE 2; PAN2","url":"https://www.omim.org/entry/617447"},{"mim_id":"604679","title":"POLYADENYLATE-BINDING PROTEIN, CYTOPLASMIC, 1; PABPC1","url":"https://www.omim.org/entry/604679"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/PAN3"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q58A45","domains":[{"cath_id":"1.10.510.10","chopping":"469-596_610-745","consensus_level":"medium","plddt":89.372,"start":469,"end":745},{"cath_id":"1.10.287.3700","chopping":"765-885","consensus_level":"high","plddt":89.1707,"start":765,"end":885}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q58A45","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q58A45-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q58A45-F1-predicted_aligned_error_v6.png","plddt_mean":62.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PAN3","jax_strain_url":"https://www.jax.org/strain/search?query=PAN3"},"sequence":{"accession":"Q58A45","fasta_url":"https://rest.uniprot.org/uniprotkb/Q58A45.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q58A45/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q58A45"}},"corpus_meta":[{"pmid":"23337855","id":"PMC_23337855","title":"RNA 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Deadenylase.","date":"2019","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/31104843","citation_count":82,"is_preprint":false},{"pmid":"24872509","id":"PMC_24872509","title":"Structural basis for Pan3 binding to Pan2 and its function in mRNA recruitment and deadenylation.","date":"2014","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/24872509","citation_count":55,"is_preprint":false},{"pmid":"32135167","id":"PMC_32135167","title":"MicroRNA-31-5p attenuates doxorubicin-induced cardiotoxicity via quaking and circular RNA Pan3.","date":"2020","source":"Journal of molecular and cellular cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/32135167","citation_count":50,"is_preprint":false},{"pmid":"24450649","id":"PMC_24450649","title":"mRNA deadenylation by Pan2-Pan3.","date":"2014","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/24450649","citation_count":49,"is_preprint":false},{"pmid":"24880344","id":"PMC_24880344","title":"The structure of the Pan2-Pan3 core complex reveals cross-talk between deadenylase and pseudokinase.","date":"2014","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/24880344","citation_count":46,"is_preprint":false},{"pmid":"22402495","id":"PMC_22402495","title":"The Caenorhabditis elegans GW182 protein AIN-1 interacts with PAB-1 and subunits of the PAN2-PAN3 and CCR4-NOT deadenylase complexes.","date":"2012","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/22402495","citation_count":44,"is_preprint":false},{"pmid":"11953437","id":"PMC_11953437","title":"Posttranscriptional regulation of the RAD5 DNA repair gene by the Dun1 kinase and the Pan2-Pan3 poly(A)-nuclease complex contributes to survival of replication blocks.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11953437","citation_count":33,"is_preprint":false},{"pmid":"37270931","id":"PMC_37270931","title":"Sevoflurane exerts protection against myocardial ischemia-reperfusion injury and pyroptosis through the circular RNA PAN3/microRNA-29b-3p/stromal cell-derived factor 4 axis.","date":"2023","source":"International immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/37270931","citation_count":23,"is_preprint":false},{"pmid":"28559491","id":"PMC_28559491","title":"Antagonistic actions of two human Pan3 isoforms on global mRNA turnover.","date":"2017","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/28559491","citation_count":13,"is_preprint":false},{"pmid":"29560286","id":"PMC_29560286","title":"PAN3-PSMA2 fusion resulting from a novel t(7;13)(p14;q12) chromosome translocation in a myelodysplastic syndrome that evolved into acute myeloid leukemia.","date":"2018","source":"Experimental hematology & oncology","url":"https://pubmed.ncbi.nlm.nih.gov/29560286","citation_count":11,"is_preprint":false},{"pmid":"25446091","id":"PMC_25446091","title":"Arsenite inhibits mRNA 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Diagnostic Biomarker: Integrated Systems Biology Investigation.","date":"2025","source":"Journal of molecular neuroscience : MN","url":"https://pubmed.ncbi.nlm.nih.gov/40227518","citation_count":1,"is_preprint":false},{"pmid":"41275497","id":"PMC_41275497","title":"Mechanisms governing poly(A)-tail-length specificity of the human PAN2-PAN3 deadenylase complex.","date":"2025","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/41275497","citation_count":0,"is_preprint":false},{"pmid":"41502505","id":"PMC_41502505","title":"Pan-Cancer Analysis of Enhancer-Induced PAN3-AS1 and Experimental Validation as a WFDC13-Promoting Factor in Colon Cancer.","date":"2025","source":"Oncology research","url":"https://pubmed.ncbi.nlm.nih.gov/41502505","citation_count":0,"is_preprint":false},{"pmid":"41556236","id":"PMC_41556236","title":"Pan2-Pan3 Complex-Mediated Deadenylation Enforces mRNA Quality Control for Infection of the Rice Blast Fungus.","date":"2026","source":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/41556236","citation_count":0,"is_preprint":false},{"pmid":"41380677","id":"PMC_41380677","title":"Cryo-EM structure of cyanopodophage Pan3 reveals a modular tail architecture for host recognition.","date":"2025","source":"Structure (London, England : 1993)","url":"https://pubmed.ncbi.nlm.nih.gov/41380677","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.09.27.678968","title":"RNA-binding proteins provide specificity to the PAN2–PAN3 mRNA deadenylation complex","date":"2025-09-27","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.27.678968","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":12015,"output_tokens":3358,"usd":0.043208,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10927,"output_tokens":3633,"usd":0.07273,"stage2_stop_reason":"end_turn"},"total_usd":0.115938,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1996,\n      \"finding\": \"Pan3p (76-kDa subunit) is required for PAN (poly(A) nuclease) enzymatic activity in yeast; deletion of PAN3 abolishes PAN activity in cell extracts, immunodepletion of Pan3p from purified PAN fractions eliminates activity, and Pan2p and Pan3p physically interact by coimmunoprecipitation and two-hybrid assay. Both subunits are required for in vivo poly(A) tail shortening.\",\n      \"method\": \"Genetic deletion, enzymatic activity assay in yeast extracts, immunodepletion, coimmunoprecipitation, two-hybrid assay, in vivo poly(A) tail length analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (deletion, biochemical activity assay, immunodepletion, Co-IP, two-hybrid, in vivo poly(A) measurement) in founding mechanistic paper\",\n      \"pmids\": [\"8816488\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The Dun1 kinase forkhead-associated domain interacts with the Pan3 subunit of the poly(A)-nuclease complex; dun1/pan2 and dun1/pan3 double mutants are hypersensitive to replication stress, and Dun1 and Pan2-Pan3 cooperate to regulate posttranscriptional control of the RAD5 DNA repair gene, which is specifically up-regulated in dun1/pan2 double mutants.\",\n      \"method\": \"Yeast two-hybrid (Dun1 FHA domain–Pan3 interaction), genetic double-mutant phenotypic analysis, replication stress sensitivity assay, gene expression analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — two-hybrid interaction plus genetic epistasis with defined phenotypic readout, single lab\",\n      \"pmids\": [\"11953437\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"C. elegans AIN-1 (GW182 homolog) interacts with PAN3 (as well as PAB-1 and NOT1/NOT2), demonstrating that GW182-family recruitment of the PAN2-PAN3 deadenylase complex is evolutionarily conserved in C. elegans miRNA-mediated silencing.\",\n      \"method\": \"Coimmunoprecipitation, directed protein interaction assays in C. elegans and Drosophila cell contexts\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP-based interaction, replicated across species contexts in single study\",\n      \"pmids\": [\"22402495\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Crystal structure of PAN3 reveals it forms asymmetric homodimers via a coiled coil linking an N-terminal pseudokinase to a C-terminal knob domain. The knob domain contains the binding surface for PAN2. A tryptophan-binding pocket at the dimer interface mediates binding to TNRC6C (GW182), enabling PAN2-PAN3 recruitment to miRNA targets. PAN3 pseudokinase binds ATP, and this ATP-binding function is required for mRNA deadenylation in vivo.\",\n      \"method\": \"X-ray crystallography, in vivo deadenylation assay, mutagenesis of binding surfaces, cell-based interaction assays with TNRC6C\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure combined with mutagenesis and in vivo functional validation in single rigorous study\",\n      \"pmids\": [\"23932717\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Crystal structure of the Pan2-Pan3 core complex (~200 kDa) shows a 1:2 (Pan2:Pan3) stoichiometry imposed by the asymmetric Pan3 homodimer. An extended region of Pan2 wraps around Pan3 as the major anchoring point. A Pan2 module formed by the pseudo-ubiquitin-hydrolase and RNase domains latches onto the Pan3 pseudokinase, orienting the deadenylase active site toward the A-binding site of Pan3. Recombinant yeast Pan2-Pan3 can deadenylate RNA in vitro without Pab1.\",\n      \"method\": \"X-ray crystallography of recombinant complex, in vitro deadenylation assay\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with in vitro reconstitution, multiple orthogonal approaches in single study\",\n      \"pmids\": [\"24880344\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Pan3 directly binds poly(A) RNA through two regions: an N-terminal zinc finger that binds poly(A) specifically, and its pseudokinase/C-terminal domain. Isolated Pan2 cannot bind RNA. Pan3 binds the linker region of Pan2 connecting its WD40 domain to the exonuclease domain with 2:1 (Pan3:Pan2) stoichiometry. Crystal structure of the Pan2 linker–Pan3 homodimer complex shows how Pan3 asymmetry creates a high-affinity interaction, enabling Pan3 to supply Pan2 with poly(A) substrate.\",\n      \"method\": \"RNA-binding assays, crystal structure of Pan2 linker–Pan3 complex, stoichiometry determination, in vitro deadenylation assays\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus direct RNA-binding biochemistry and stoichiometry determination in single rigorous study\",\n      \"pmids\": [\"24872509\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Arsenite-induced oxidative stress inhibits mRNA deadenylation through proteolytic degradation of Pan3 (and Tob). siRNA knockdown of Pan3 alone recapitulates global poly(A) tail stabilization seen during arsenite stress, establishing Pan3 as an essential mediator of deadenylase recruitment under stress conditions.\",\n      \"method\": \"Arsenite treatment, siRNA knockdown, poly(A) tail length analysis, protein degradation assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — siRNA knockdown with defined molecular phenotype (poly(A) tail stabilization), single lab\",\n      \"pmids\": [\"25446091\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Two human PAN3 isoforms (Pan3S and Pan3L) have opposing activities: Pan3S interacts more strongly with PABP and enhances Pan2 deadenylase activity, while Pan3L suppresses Pan2 activity. Knockdown of individual isoforms has opposing effects on global poly(A) tail length, P-body formation, and mRNA decay pathways, revealing that the two isoforms coordinate the first phase of biphasic deadenylation.\",\n      \"method\": \"Isoform-specific knockdown, global poly(A) tail profiling, transcriptome-wide mRNA stability analysis, PABP interaction assays, P-body imaging\",\n      \"journal\": \"RNA (New York, N.Y.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (knockdown, transcriptome-wide profiling, binding assays, imaging) in single lab study\",\n      \"pmids\": [\"28559491\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Cryo-EM structure of Pan2-Pan3 in complex with a poly(A) RNP (90 adenosines + three Pab1 protomers) shows that Pan2-Pan3 recognizes the oligomerization interfaces of Pab1 via conserved features of the deadenylase and threads the poly(A) RNA substrate into the nuclease active site. Pan2-Pan3 associates with and degrades poly(A) RNPs containing two or more Pab1 molecules. This reveals how Pab1 oligomers act as rulers for poly(A) tail length.\",\n      \"method\": \"Cryo-EM structure determination, in vitro reconstitution with recombinant proteins, deadenylation activity assays\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure combined with in vitro reconstitution and activity assays in single rigorous study\",\n      \"pmids\": [\"31104843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Pan2 and Pan3 are phosphorylated when yeast are switched to non-fermentable carbon sources (glycerol-lactate), suggesting their activities are regulated by phosphorylation in response to carbon source changes. The Pan2-Pan3 complex cooperates with Ccr4-Not for growth on non-fermentable carbon sources.\",\n      \"method\": \"Genetic deletion analysis, growth assays on non-fermentable carbon media, multicopy suppressor screen, phosphorylation detection\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — phosphorylation detected but writer/eraser not identified; single lab, single method for phosphorylation claim\",\n      \"pmids\": [\"34280615\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cryo-EM structures of human PAN2-PAN3 bound to poly(A)-PABPC1 ribonucleoproteins reveal a longer substrate-binding path in the human deadenylase compared to the fungal ortholog, providing structural basis for the co-evolution of deadenylase properties with the longer poly(A) tails characteristic of mammalian mRNAs. Human PAN2-PAN3 shows greater deadenylation activity on long poly(A)-PABPC1 substrates in vitro.\",\n      \"method\": \"Cryo-EM structure determination, in vitro deadenylation assays with poly(A) RNAs up to 240 nt, comparative structural analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cryo-EM structure with in vitro activity assays, single lab but orthogonal methods\",\n      \"pmids\": [\"41275497\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PAN2-PAN3 can be recruited to specific mRNAs via RNA-binding protein (RBP) adaptors, including MEX3, YTHDF, and ZFP36 proteins, as demonstrated by biochemical reconstitution. In cells, a diverse range of RNA adaptors interact with both PAN2-PAN3 and CCR4-NOT, indicating PAN2-PAN3 contributes to transcript-specific mRNA degradation beyond general PABP-dependent recruitment.\",\n      \"method\": \"Biochemical reconstitution, affinity pulldown/interaction assays in cells\",\n      \"journal\": \"bioRxiv (preprint)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — biochemical reconstitution plus cell-based interaction assays, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.09.27.678968\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"PAN3 is an essential non-catalytic subunit of the conserved eukaryotic PAN2-PAN3 deadenylase complex that functions as an asymmetric homodimer: it directly binds poly(A) RNA via an N-terminal zinc finger, recruits the PAN2 exonuclease (in a 2:1 PAN3:PAN2 stoichiometry) through contacts between its knob domain and a Pan2 linker region, and orients the PAN2 nuclease active site toward substrate; the complex specifically recognizes poly(A)-PABP oligomeric ribonucleoproteins to catalyze the initial, length-sensitive phase of cytoplasmic deadenylation, and is additionally recruited to miRNA-target mRNAs via a tryptophan-binding pocket in its pseudokinase dimer interface that engages GW182/TNRC6 proteins, and to other specific transcripts via RNA-binding protein adaptors such as MEX3, YTHDF, and ZFP36.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PAN3 is an essential, non-catalytic subunit of the conserved eukaryotic PAN2-PAN3 deadenylase that drives the initial, length-sensitive phase of cytoplasmic poly(A) tail shortening [#0, #8]. Although required for poly(A) nuclease activity in vivo, PAN3 itself is catalytically inert; it functions as an asymmetric homodimer built from an N-terminal pseudokinase and a C-terminal knob domain joined by a coiled coil, with the knob providing the binding surface for the PAN2 exonuclease [#3]. PAN3 supplies substrate and architecture to the complex: it binds poly(A) RNA directly through an N-terminal zinc finger and its pseudokinase domain, engages a PAN2 linker region with 2:1 (PAN3:PAN2) stoichiometry, and orients the PAN2 nuclease active site toward the poly(A) substrate [#4, #5]. The reconstituted complex recognizes poly(A)-PABP oligomeric ribonucleoproteins, degrading tails decorated with two or more PABP/Pab1 protomers so that PABP oligomers act as molecular rulers for tail length [#8], a substrate-binding path that has co-evolved with the longer poly(A) tails of mammalian mRNAs [#10]. Beyond bulk PABP-dependent deadenylation, PAN3 confers transcript specificity: a tryptophan-binding pocket at its pseudokinase dimer interface engages GW182/TNRC6 proteins to recruit the complex to miRNA targets [#2, #3], and additional RNA-binding adaptors such as MEX3, YTHDF, and ZFP36 direct it to specific transcripts [#11]. PAN3 is also a regulatory node, mediating deadenylase recruitment under oxidative stress, where its proteolytic degradation stabilizes poly(A) tails [#6], and two human isoforms exert opposing effects on PAN2 activity and global tail length [#7].\",\n  \"teleology\": [\n    {\n      \"year\": 1996,\n      \"claim\": \"Established that PAN3 is a required subunit of the poly(A) nuclease, answering whether deadenylase activity depends on more than the catalytic subunit.\",\n      \"evidence\": \"Genetic deletion, immunodepletion, Co-IP, two-hybrid, and in vivo poly(A) measurement in yeast\",\n      \"pmids\": [\"8816488\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define which PAN3 region contacts PAN2\", \"No structural basis for how PAN3 enables catalysis\", \"Catalytic versus non-catalytic role of PAN3 not resolved\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Linked Pan2-Pan3 to a stress-response pathway, showing the deadenylase participates in post-transcriptional control of a DNA repair transcript.\",\n      \"evidence\": \"Yeast two-hybrid (Dun1 FHA-Pan3) plus genetic epistasis and gene-expression analysis under replication stress\",\n      \"pmids\": [\"11953437\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct deadenylation of RAD5 mRNA not demonstrated biochemically\", \"Whether Dun1 phosphorylates Pan3 unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed GW182-family recruitment of PAN2-PAN3 in miRNA silencing is evolutionarily conserved, generalizing the targeting mechanism beyond a single species.\",\n      \"evidence\": \"Co-IP and directed interaction assays of C. elegans AIN-1 with PAN3 in worm/fly contexts\",\n      \"pmids\": [\"22402495\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Co-IP without structural mapping of the interface\", \"Functional consequence for specific miRNA targets not quantified\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Defined PAN3 domain architecture and the molecular basis of miRNA-target recruitment, explaining how a pseudokinase scaffold engages GW182.\",\n      \"evidence\": \"X-ray crystallography with mutagenesis and in vivo deadenylation and TNRC6C interaction assays\",\n      \"pmids\": [\"23932717\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why ATP binding is needed for deadenylation not mechanistically resolved\", \"Did not capture the PAN2-bound complex\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Resolved the assembled PAN2-PAN3 core and how PAN3 asymmetry imposes 2:1 stoichiometry, orients the nuclease, and supplies poly(A) substrate via its zinc finger.\",\n      \"evidence\": \"Crystal structures of the Pan2-Pan3 core and Pan2 linker-Pan3 complex with RNA-binding biochemistry and in vitro deadenylation\",\n      \"pmids\": [\"24880344\", \"24872509\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not show how the complex reads poly(A) tail length\", \"Role of PABP in substrate engagement not yet structural\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identified PAN3 as a stress-responsive regulatory node whose degradation stabilizes poly(A) tails, connecting deadenylase recruitment to oxidative stress.\",\n      \"evidence\": \"Arsenite treatment, siRNA knockdown, and poly(A) tail length and protein-degradation assays\",\n      \"pmids\": [\"25446091\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Protease responsible for PAN3 degradation not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showed two human PAN3 isoforms exert opposing control over PAN2 activity and global tail length, revealing isoform-level tuning of the first deadenylation phase.\",\n      \"evidence\": \"Isoform-specific knockdown, transcriptome-wide poly(A) and stability profiling, PABP-interaction and P-body imaging\",\n      \"pmids\": [\"28559491\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis for opposing isoform activities unknown\", \"How isoform ratio is set physiologically unclear\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Provided the structural mechanism for length-sensitive deadenylation, showing PABP/Pab1 oligomers serve as rulers recognized by the complex.\",\n      \"evidence\": \"Cryo-EM of Pan2-Pan3 bound to a poly(A)-Pab1 RNP with in vitro reconstitution and activity assays\",\n      \"pmids\": [\"31104843\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How the complex transitions from initial to processive trimming not fully defined\", \"Cross-talk with Ccr4-Not at the same substrate unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Suggested metabolic regulation of the deadenylase, detecting Pan2/Pan3 phosphorylation upon carbon-source shift and cooperation with Ccr4-Not.\",\n      \"evidence\": \"Genetic deletion, growth assays on non-fermentable media, suppressor screen, and phosphorylation detection in yeast\",\n      \"pmids\": [\"34280615\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Kinase/phosphatase acting on Pan3 not identified\", \"Functional consequence of phosphorylation not demonstrated\", \"Single lab, single method for phospho-claim\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated co-evolution of human deadenylase substrate-binding architecture with longer mammalian poly(A) tails.\",\n      \"evidence\": \"Cryo-EM of human PAN2-PAN3 with poly(A)-PABPC1 RNPs and comparative in vitro deadenylation on long substrates\",\n      \"pmids\": [\"41275497\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In-cell relevance of the longer substrate path not tested\", \"Regulation of human-specific features unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Expanded targeting logic beyond PABP, showing diverse RBP adaptors recruit PAN2-PAN3 for transcript-specific decay.\",\n      \"evidence\": \"Biochemical reconstitution with MEX3/YTHDF/ZFP36 and cell-based interaction assays (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.09.27.678968\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Which PAN3 surfaces engage each adaptor not mapped\", \"Transcript-level decay consequences not fully quantified\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How PAN3 phosphorylation, isoform balance, and competing adaptor inputs are integrated to control deadenylase activity and target selection in vivo remains open.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No identified PAN3 kinase/phosphatase\", \"Mechanism coordinating PABP-dependent versus adaptor-dependent recruitment unknown\", \"In-cell dynamics of isoform-specific regulation undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [5, 8]},\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [3, 5]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0, 8]}\n    ],\n    \"complexes\": [\"PAN2-PAN3 deadenylase\"],\n    \"partners\": [\"PAN2\", \"PABPC1\", \"TNRC6C\", \"AIN-1\", \"MEX3\", \"YTHDF\", \"ZFP36\", \"DUN1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}