{"gene":"LAS1L","run_date":"2026-06-10T02:59:49","timeline":{"discoveries":[{"year":2010,"finding":"LAS1L is a nucleolar protein required for ribosome biogenesis; depletion of LAS1L inhibits rRNA processing, blocks synthesis of mature 28S rRNA, and causes p53-dependent G1 cell cycle arrest, establishing its essential role in 60S ribosomal subunit biogenesis.","method":"siRNA knockdown, rRNA processing assays (Northern blot), flow cytometry, p53 pathway analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean knockdown with multiple orthogonal readouts (rRNA processing, cell cycle arrest, p53 dependence), replicated in subsequent studies","pmids":["20647540"],"is_preprint":false},{"year":2011,"finding":"LAS1L forms a novel nucleolar complex with PELP1, TEX10, WDR18 (mammalian Rix1 complex), NOL9, and SENP3 that co-fractionates with the 60S preribosomal subunit; depletion of complex members causes defects in ITS2 pre-rRNA processing and p53-dependent G1 arrest; nucleolar localization of this complex requires active RNA Pol I transcription and SENP3.","method":"Co-immunoprecipitation, sucrose gradient fractionation, siRNA knockdown, rRNA processing assays, immunofluorescence","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, fractionation, functional knockdown with defined molecular phenotype, multiple orthogonal methods","pmids":["22190735"],"is_preprint":false},{"year":2011,"finding":"LAS1L and PELP1 are SUMO targets sensitive to the SUMO-specific protease SENP3; balanced SUMO conjugation/deconjugation controls the nucleolar partitioning of the PELP1-TEX10-WDR18-LAS1L complex, thereby coordinating the rate of ribosome formation and nucleolar release of the large ribosomal subunit.","method":"Biochemical purification, SUMO modification assays, SENP3 depletion, subcellular fractionation, Co-IP","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — biochemical purification combined with functional SUMO modification assays and localization experiments, replicated across two independent labs","pmids":["21326211"],"is_preprint":false},{"year":2012,"finding":"In S. cerevisiae, Las1 (ortholog of LAS1L) co-precipitates with 27S rRNA and associates with Nsa1/Rix1-containing pre-60S particles; Las1 interacts with Grc3 polynucleotide kinase, and the kinase activity of Grc3 is required for efficient ITS2 pre-rRNA processing; depletion of Las1 causes accumulation of 27S and 7S rRNA intermediates and impairs 60S subunit synthesis.","method":"Co-immunoprecipitation, sucrose gradient sedimentation, Northern blot, kinase-dead Grc3 mutant analysis, yeast genetics","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — yeast ortholog biochemically characterized with reciprocal Co-IP, rRNA intermediate analysis, and catalytic mutant validation","pmids":["23175604"],"is_preprint":false},{"year":2012,"finding":"LAS1L is a component of the Five Friends of Methylated CHTOP (5FMC) nuclear complex, consisting of PELP1, SENP3, WDR18, TEX10, and LAS1L; PELP1 functions as the core scaffold, as other components (including LAS1L) become unstable in its absence; the complex is recruited to CHTOP only when CHTOP is arginine-methylated by PRMT1, linking arginine methylation to desumoylation of transcriptional targets.","method":"Biotinylation-proteomics pulldown, Co-IP, siRNA knockdown stability assays, sumoylation assays","journal":"Molecular & cellular proteomics : MCP","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — proteomics-based pulldown with functional follow-up on complex stability, single lab","pmids":["22872859"],"is_preprint":false},{"year":2014,"finding":"A de novo mutation in LAS1L (p.S477N) causes congenital lethal motor neuron disease; morpholino knockdown of las1l in zebrafish causes early lethality and disruption of muscle and peripheral nerve architecture, partially rescued by wild-type but not mutant human LAS1L RNA, confirming that disruption of 60S ribosomal subunit maturation is the pathogenic mechanism.","method":"Exome sequencing, zebrafish morpholino knockdown, RNA rescue experiment","journal":"Neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo model with wild-type vs. mutant RNA rescue, single lab","pmids":["24647030"],"is_preprint":false},{"year":2019,"finding":"Human LAS1L and NOL9 form a higher-order endonuclease-kinase complex that catalyzes ITS2 pre-rRNA cleavage and 5'-hydroxyl phosphorylation; a Nol9-encoded nucleolar localization sequence (NoLS) is required for nucleolar transport of the assembled Las1L-Nol9 complex; structural analysis by high-resolution imaging defines their spatial organization within the nucleolar sub-structure linked to late pre-rRNA processing.","method":"Co-immunoprecipitation, deletion mapping of NoLS, high-resolution fluorescence imaging, functional rRNA processing assays","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — complex assembly characterized with Co-IP, NoLS functionally mapped, spatial localization determined by imaging, enzymatic activities defined","pmids":["31288032"],"is_preprint":false},{"year":2020,"finding":"Las1 possesses HEPN endoribonuclease domains; both HEPN nuclease motifs (RφXXXH) are required for nuclease activity and fidelity; systematic mutagenesis of individual HEPN motif residues and reconstituted HEPN-HEPN' chimeras showed that both motifs contribute to coordinating RNA in the active site; conformational flexibility between the two HEPN domains is required for proper RNA cleavage.","method":"In vitro endoribonuclease assays, systematic mutagenesis of active-site residues, HEPN chimera reconstitution, in vivo yeast complementation assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with systematic mutagenesis and in vivo validation, multiple orthogonal approaches","pmids":["32220933"],"is_preprint":false},{"year":2021,"finding":"Depletion of LAS1L (along with PELP1 and NOP2) or inhibition of RNA Pol I induces nucleolar stress that triggers p53-dependent transcriptional programming promoting metabolic remodeling and autophagy (rather than apoptosis) in solid tumor cell lines; blocking autophagy sensitizes cancer cells to RNA Pol I inhibition, placing LAS1L in the nucleolar stress–p53–autophagy axis.","method":"siRNA knockdown, RNA Pol I inhibitor (CX-5461), gene expression analysis, autophagy assays, cell death/cell cycle assays","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional knockdown with defined pathway placement using multiple molecular tools, single lab","pmids":["34319761"],"is_preprint":false},{"year":2021,"finding":"LAS1L protein expression is elevated in triple-negative breast cancer (TNBC); β-catenin inhibition decreases LAS1L abundance in the nucleolus; LAS1L functionally enables mammary tumor growth in xenograft models and invasive attributes of TNBC cells, placing LAS1L downstream of β-catenin signaling in TNBC.","method":"Nucleolar proteomics, β-catenin inhibitor treatment, xenograft tumor growth assays, invasion assays","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — proteomics plus functional in vivo xenograft validation, single lab","pmids":["33664239"],"is_preprint":false},{"year":2022,"finding":"hnRNPA1 directly binds two specific intronic sites (UAGGGU and UGGGGU) of LAS1L pre-mRNA to inhibit splicing of LAS1L exon 9; knockdown of hnRNPA1 shifts the LAS1L-L/LAS1L-S isoform ratio and promotes migration, invasion, and EMT in lung cancer cells, establishing hnRNPA1 as a regulator of LAS1L alternative splicing.","method":"RNA immunoprecipitation (RIP), RNA pulldown, AGE splicing assays, Transwell migration/invasion assays","journal":"Frontiers in oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct RNA-protein binding confirmed by RIP and pulldown, functional consequence measured, single lab","pmids":["35814393"],"is_preprint":false},{"year":2024,"finding":"The nucleolar deubiquitinase USP36 interacts with both LAS1L and NOL9, stabilizes them via deubiquitination, and mediates SUMOylation of LAS1L at lysine 565 (K565); the K565R mutation abolishes LAS1L function in ITS2 pre-rRNA processing without affecting LAS1L stability or Las1L-Nol9 complex formation, demonstrating that USP36-mediated LAS1L SUMOylation is specifically required for ITS2 cleavage.","method":"Co-immunoprecipitation, ubiquitination/SUMOylation assays, site-directed mutagenesis (K565R), ITS2 processing rescue assays (knockdown + re-expression of WT vs. mutant)","journal":"Cancer research communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — site-specific mutagenesis separates SUMOylation from complex formation, functional rescue assay validates the modification's role in catalysis, multiple orthogonal biochemical approaches","pmids":["39356143"],"is_preprint":false},{"year":2025,"finding":"Cryo-EM structures of human PELP1-WDR18-TEX10 and LAS1L-NOL9 complexes, plus a lower-resolution model of PELP1-WDR18-LAS1L, reveal that LAS1L is recruited to the rixosome core scaffold (PELP1-WDR18-TEX10-LAS1L) via an interaction between the C-terminal helix of WDR18 and the helical domain of LAS1L; truncation of the WDR18 C-terminal helix abolishes LAS1L binding; TEX10 contacts WDR18 at two separate regions, both required for binding.","method":"Cryo-EM structure determination, mutagenesis (truncation and point mutations of WDR18-TEX10 interfaces), biochemical binding assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structures with mutagenesis validation of key interfaces, multiple orthogonal structural and biochemical methods in single rigorous study","pmids":["40195365"],"is_preprint":false}],"current_model":"LAS1L is an essential nucleolar HEPN endoribonuclease that, as part of the rixosome complex (with PELP1, WDR18, TEX10, NOL9, and SENP3), cleaves ITS2 of pre-rRNA and partners with the NOL9 polynucleotide kinase to phosphorylate the cleavage product, driving 60S ribosomal subunit maturation; its nucleolar localization depends on a Nol9-encoded localization sequence, its activity requires both HEPN motifs acting together, and its function is regulated by USP36-mediated deubiquitination and SUMOylation at K565, while SUMO-controlled nucleolar partitioning of the complex coordinates ribosome biogenesis rate; loss of LAS1L function triggers p53-dependent G1 arrest and nucleolar stress-induced autophagy."},"narrative":{"mechanistic_narrative":"LAS1L is an essential nucleolar factor that drives maturation of the 60S large ribosomal subunit by catalyzing cleavage of the ITS2 spacer within pre-rRNA, and its depletion blocks 28S rRNA synthesis and triggers p53-dependent G1 arrest [PMID:20647540]. It executes this step as the endoribonuclease of a HEPN-domain enzyme: both RφXXXH HEPN motifs and conformational flexibility between the two HEPN domains are required to coordinate RNA in the active site and achieve faithful cleavage [PMID:32220933]. LAS1L partners with the NOL9 polynucleotide kinase to form a higher-order endonuclease–kinase complex that cleaves ITS2 and phosphorylates the resulting 5'-hydroxyl product, with a NOL9-encoded nucleolar localization sequence directing the assembled complex into the nucleolus [PMID:23175604, PMID:31288032]. LAS1L is integrated into a larger nucleolar complex (the mammalian Rix1/rixosome) with PELP1, TEX10, WDR18, NOL9, and SENP3 that co-fractionates with pre-60S particles, where it is recruited to the PELP1-WDR18-TEX10 scaffold through an interface between the WDR18 C-terminal helix and the LAS1L helical domain [PMID:22190735, PMID:40195365]. Two post-translational modification systems govern LAS1L activity and complex behavior: SUMO conjugation balanced by the SENP3 protease controls nucleolar partitioning of the complex and the rate of ribosome formation [PMID:21326211], while the deubiquitinase USP36 stabilizes LAS1L and mediates its SUMOylation at K565, a modification specifically required for ITS2 cleavage but dispensable for complex assembly [PMID:39356143]. A de novo LAS1L mutation (p.S477N) causes congenital lethal motor neuron disease through disrupted 60S maturation [PMID:24647030]. Beyond ribosome biogenesis, loss of LAS1L produces nucleolar stress that engages a p53-dependent autophagy program, and LAS1L supports tumor growth in breast and lung cancer contexts [PMID:34319761, PMID:33664239].","teleology":[{"year":2010,"claim":"Established that LAS1L is a nucleolar protein essential for large-subunit ribosome biogenesis, answering whether it has a defined functional role rather than being merely nucleolus-localized.","evidence":"siRNA knockdown with Northern blot rRNA processing assays, flow cytometry, and p53 pathway analysis in human cells","pmids":["20647540"],"confidence":"High","gaps":["Did not define the molecular activity of LAS1L itself","Did not identify protein partners or the specific processing step"]},{"year":2011,"claim":"Defined the multiprotein context of LAS1L by placing it in a nucleolar complex with PELP1, TEX10, WDR18, NOL9, and SENP3 acting at ITS2 processing, moving from a single protein to a functional module.","evidence":"Reciprocal Co-IP, sucrose gradient fractionation, siRNA knockdown with rRNA processing assays, and immunofluorescence","pmids":["22190735"],"confidence":"High","gaps":["Did not assign catalytic roles to individual subunits","Mechanism of nucleolar recruitment not resolved at the structural level"]},{"year":2011,"claim":"Showed that SUMO conjugation/deconjugation controlled by SENP3 governs nucleolar partitioning of the LAS1L-containing complex, explaining how ribosome formation rate is regulated.","evidence":"Biochemical purification, SUMO modification assays, SENP3 depletion, and subcellular fractionation","pmids":["21326211"],"confidence":"High","gaps":["SUMO acceptor site on LAS1L not mapped here","Causal link between SUMO state and catalytic step not established"]},{"year":2012,"claim":"Yeast ortholog work revealed that Las1 associates with pre-60S particles and the Grc3 polynucleotide kinase, whose kinase activity is needed for ITS2 processing, establishing the conserved endonuclease-kinase partnership.","evidence":"Co-IP, sucrose gradient sedimentation, Northern blot, and kinase-dead Grc3 mutant analysis in S. cerevisiae","pmids":["23175604"],"confidence":"High","gaps":["Did not demonstrate LAS1L's own nuclease activity directly","Catalytic mechanism of cleavage unresolved"]},{"year":2012,"claim":"Identified the same subunits as the 5FMC complex recruited to arginine-methylated CHTOP, with PELP1 as the stabilizing scaffold, broadening the complex's role beyond rRNA processing to methylation-linked desumoylation.","evidence":"Biotinylation-proteomics pulldown, Co-IP, knockdown stability assays, and sumoylation assays","pmids":["22872859"],"confidence":"Medium","gaps":["Single-lab proteomics, the CHTOP link not independently validated","Direct role of LAS1L in this function not isolated"]},{"year":2014,"claim":"Linked LAS1L to human disease by showing a de novo p.S477N mutation causes congenital lethal motor neuron disease via impaired 60S maturation.","evidence":"Exome sequencing plus zebrafish morpholino knockdown with wild-type vs. mutant RNA rescue","pmids":["24647030"],"confidence":"Medium","gaps":["Single family/single lab","Molecular effect of S477N on catalysis or complex assembly not defined"]},{"year":2019,"claim":"Reconstituted the human LAS1L-NOL9 endonuclease-kinase complex and showed a NOL9-encoded NoLS directs its nucleolar transport, defining the spatial logic of late pre-rRNA processing.","evidence":"Co-IP, deletion mapping of the NoLS, high-resolution fluorescence imaging, and rRNA processing assays","pmids":["31288032"],"confidence":"High","gaps":["Atomic structure of the active site not yet determined","How the complex docks onto pre-60S not resolved"]},{"year":2020,"claim":"Defined LAS1L's catalytic mechanism by showing both HEPN motifs and inter-domain flexibility are required for faithful RNA cleavage, identifying it as the endoribonuclease.","evidence":"In vitro endoribonuclease assays, systematic active-site mutagenesis, HEPN chimera reconstitution, and yeast complementation","pmids":["32220933"],"confidence":"High","gaps":["Mostly yeast/orthologous system","Precise RNA substrate recognition determinants not fully mapped"]},{"year":2021,"claim":"Placed LAS1L in a nucleolar stress–p53–autophagy axis, showing its loss drives metabolic remodeling and autophagy rather than apoptosis in tumor cells.","evidence":"siRNA knockdown, RNA Pol I inhibition (CX-5461), gene expression and autophagy assays in solid tumor lines","pmids":["34319761"],"confidence":"Medium","gaps":["Single lab","Mechanism distinguishing autophagy from apoptosis downstream of p53 not detailed"]},{"year":2021,"claim":"Connected LAS1L to oncogenic signaling by showing it is elevated in TNBC downstream of β-catenin and supports tumor growth and invasion.","evidence":"Nucleolar proteomics, β-catenin inhibitor treatment, xenograft growth and invasion assays","pmids":["33664239"],"confidence":"Medium","gaps":["Single lab","Whether the tumor phenotype reflects ribosome biogenesis or a separate activity not resolved"]},{"year":2022,"claim":"Identified hnRNPA1 as a direct regulator of LAS1L alternative splicing, showing it binds intronic sites to control exon 9 inclusion and the LAS1L-L/S isoform ratio in cancer.","evidence":"RNA immunoprecipitation, RNA pulldown, splicing assays, and Transwell migration/invasion assays in lung cancer cells","pmids":["35814393"],"confidence":"Medium","gaps":["Single lab","Functional difference between LAS1L-L and LAS1L-S isoforms in ribosome biogenesis not established"]},{"year":2024,"claim":"Resolved a regulatory mechanism by showing USP36 stabilizes LAS1L and mediates K565 SUMOylation specifically required for ITS2 cleavage, decoupling this modification from complex assembly.","evidence":"Co-IP, ubiquitination/SUMOylation assays, K565R mutagenesis, and ITS2 processing rescue with WT vs. mutant re-expression","pmids":["39356143"],"confidence":"High","gaps":["How K565 SUMOylation alters catalysis mechanistically not shown","Single lab"]},{"year":2025,"claim":"Provided the structural basis for rixosome assembly, showing LAS1L is recruited via the WDR18 C-terminal helix contacting its helical domain, explaining how the endonuclease is integrated into the scaffold.","evidence":"Cryo-EM of PELP1-WDR18-TEX10 and LAS1L-NOL9, plus mutagenesis of interface residues and binding assays","pmids":["40195365"],"confidence":"High","gaps":["Full assembled rixosome with bound pre-60S not captured","Conformational coupling between scaffold binding and catalysis unresolved"]},{"year":null,"claim":"How LAS1L catalysis is conformationally coupled to scaffold recruitment, SUMOylation state, and pre-60S substrate engagement within the intact nucleolar particle remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No structure of the complete rixosome bound to pre-rRNA substrate","Mechanistic link between K565 SUMOylation and HEPN active-site activity not defined","Functional distinction between LAS1L splice isoforms unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[3,6,7,11]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[3,7]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[6,7]}],"localization":[{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[0,1,6]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0,1,3,6]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[0,1]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[8]}],"complexes":["rixosome (mammalian Rix1 complex)","5FMC complex","LAS1L-NOL9 endonuclease-kinase complex"],"partners":["NOL9","PELP1","WDR18","TEX10","SENP3","USP36","CHTOP","HNRNPA1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9Y4W2","full_name":"Ribosomal biogenesis protein LAS1L","aliases":["Endoribonuclease LAS1L","Protein LAS1 homolog"],"length_aa":734,"mass_kda":83.1,"function":"Required for the synthesis of the 60S ribosomal subunit and maturation of the 28S rRNA (PubMed:20647540). Functions as a component of the Five Friends of Methylated CHTOP (5FMC) complex; the 5FMC complex is recruited to ZNF148 by methylated CHTOP, leading to desumoylation of ZNF148 and subsequent transactivation of ZNF148 target genes (PubMed:22872859). Required for the efficient pre-rRNA processing at both ends of internal transcribed spacer 2 (ITS2) (PubMed:22083961)","subcellular_location":"Nucleus, nucleolus; Nucleus, nucleoplasm; Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q9Y4W2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/LAS1L","classification":"Common Essential","n_dependent_lines":1123,"n_total_lines":1208,"dependency_fraction":0.929635761589404},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"SLC16A10","stoichiometry":10.0},{"gene":"CAPRIN1","stoichiometry":0.2},{"gene":"CTCF","stoichiometry":0.2},{"gene":"DDOST","stoichiometry":0.2},{"gene":"DNTTIP1","stoichiometry":0.2},{"gene":"DRG1","stoichiometry":0.2},{"gene":"IPO5","stoichiometry":0.2},{"gene":"NPM1","stoichiometry":0.2},{"gene":"NPM3","stoichiometry":0.2},{"gene":"OST4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/LAS1L","total_profiled":1310},"omim":[{"mim_id":"620304","title":"NUCLEOLAR PROTEIN 9; NOL9","url":"https://www.omim.org/entry/620304"},{"mim_id":"620291","title":"WD REPEAT-CONTAINING PROTEIN 18; WDR18","url":"https://www.omim.org/entry/620291"},{"mim_id":"618738","title":"TUBULIN TYROSINE LIGASE-LIKE 4; TTLL4","url":"https://www.omim.org/entry/618738"},{"mim_id":"609455","title":"PROLINE-, GLUTAMIC ACID-, AND LEUCINE-RICH PROTEIN 1; PELP1","url":"https://www.omim.org/entry/609455"},{"mim_id":"309585","title":"INTELLECTUAL DEVELOPMENTAL DISORDER, X-LINKED, SYNDROMIC, WILSON-TURNER TYPE; WTS","url":"https://www.omim.org/entry/309585"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Primary cilium transition zone","reliability":"Additional"},{"location":"Centriolar satellite","reliability":"Additional"},{"location":"Centrosome","reliability":"Additional"},{"location":"Basal body","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/LAS1L"},"hgnc":{"alias_symbol":["FLJ12525","Las1"],"prev_symbol":[]},"alphafold":{"accession":"Q9Y4W2","domains":[{"cath_id":"-","chopping":"49-199","consensus_level":"high","plddt":81.3583,"start":49,"end":199}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y4W2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y4W2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y4W2-F1-predicted_aligned_error_v6.png","plddt_mean":62.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=LAS1L","jax_strain_url":"https://www.jax.org/strain/search?query=LAS1L"},"sequence":{"accession":"Q9Y4W2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y4W2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y4W2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y4W2"}},"corpus_meta":[{"pmid":"25644381","id":"PMC_25644381","title":"X-exome sequencing of 405 unresolved 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Part A","url":"https://pubmed.ncbi.nlm.nih.gov/26358559","citation_count":14,"is_preprint":false},{"pmid":"31288032","id":"PMC_31288032","title":"Nol9 Is a Spatial Regulator for the Human ITS2 Pre-rRNA Endonuclease-Kinase Complex.","date":"2019","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/31288032","citation_count":13,"is_preprint":false},{"pmid":"33892623","id":"PMC_33892623","title":"A worldwide map of swine short tandem repeats and their associations with evolutionary and environmental adaptations.","date":"2021","source":"Genetics, selection, evolution : GSE","url":"https://pubmed.ncbi.nlm.nih.gov/33892623","citation_count":11,"is_preprint":false},{"pmid":"35814393","id":"PMC_35814393","title":"Knockdown of hnRNPA1 Promotes NSCLC Metastasis and EMT by Regulating Alternative Splicing of LAS1L exon 9.","date":"2022","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/35814393","citation_count":9,"is_preprint":false},{"pmid":"37199805","id":"PMC_37199805","title":"Targeting PELP1 oncogenic signaling in TNBC with the small molecule inhibitor SMIP34.","date":"2023","source":"Breast cancer research and treatment","url":"https://pubmed.ncbi.nlm.nih.gov/37199805","citation_count":6,"is_preprint":false},{"pmid":"39356143","id":"PMC_39356143","title":"USP36 SUMOylates Las1L and Promotes Its Function in Pre-Ribosomal RNA ITS2 Processing.","date":"2024","source":"Cancer research communications","url":"https://pubmed.ncbi.nlm.nih.gov/39356143","citation_count":4,"is_preprint":false},{"pmid":"40195365","id":"PMC_40195365","title":"Molecular insights into the overall architecture of human rixosome.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/40195365","citation_count":3,"is_preprint":false},{"pmid":"35627110","id":"PMC_35627110","title":"Severe Infantile Axonal Neuropathy with Respiratory Failure Caused by Novel Mutation in X-Linked LAS1L Gene.","date":"2022","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/35627110","citation_count":2,"is_preprint":false},{"pmid":"29572065","id":"PMC_29572065","title":"Pericentromeric regions of homozygosity on the X chromosome: Another likely benign population variant.","date":"2018","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/29572065","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":28556,"output_tokens":6934,"usd":0.142912,"retried_sync":true,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11160,"output_tokens":4308,"usd":0.08175,"stage2_stop_reason":"end_turn"},"total_usd":0.224662,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"LAS1L is a nucleolar protein required for ribosome biogenesis; depletion of LAS1L inhibits rRNA processing, blocks synthesis of mature 28S rRNA, and causes p53-dependent G1 cell cycle arrest, establishing its essential role in 60S ribosomal subunit biogenesis.\",\n      \"method\": \"siRNA knockdown, rRNA processing assays (Northern blot), flow cytometry, p53 pathway analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean knockdown with multiple orthogonal readouts (rRNA processing, cell cycle arrest, p53 dependence), replicated in subsequent studies\",\n      \"pmids\": [\"20647540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"LAS1L forms a novel nucleolar complex with PELP1, TEX10, WDR18 (mammalian Rix1 complex), NOL9, and SENP3 that co-fractionates with the 60S preribosomal subunit; depletion of complex members causes defects in ITS2 pre-rRNA processing and p53-dependent G1 arrest; nucleolar localization of this complex requires active RNA Pol I transcription and SENP3.\",\n      \"method\": \"Co-immunoprecipitation, sucrose gradient fractionation, siRNA knockdown, rRNA processing assays, immunofluorescence\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, fractionation, functional knockdown with defined molecular phenotype, multiple orthogonal methods\",\n      \"pmids\": [\"22190735\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"LAS1L and PELP1 are SUMO targets sensitive to the SUMO-specific protease SENP3; balanced SUMO conjugation/deconjugation controls the nucleolar partitioning of the PELP1-TEX10-WDR18-LAS1L complex, thereby coordinating the rate of ribosome formation and nucleolar release of the large ribosomal subunit.\",\n      \"method\": \"Biochemical purification, SUMO modification assays, SENP3 depletion, subcellular fractionation, Co-IP\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — biochemical purification combined with functional SUMO modification assays and localization experiments, replicated across two independent labs\",\n      \"pmids\": [\"21326211\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"In S. cerevisiae, Las1 (ortholog of LAS1L) co-precipitates with 27S rRNA and associates with Nsa1/Rix1-containing pre-60S particles; Las1 interacts with Grc3 polynucleotide kinase, and the kinase activity of Grc3 is required for efficient ITS2 pre-rRNA processing; depletion of Las1 causes accumulation of 27S and 7S rRNA intermediates and impairs 60S subunit synthesis.\",\n      \"method\": \"Co-immunoprecipitation, sucrose gradient sedimentation, Northern blot, kinase-dead Grc3 mutant analysis, yeast genetics\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — yeast ortholog biochemically characterized with reciprocal Co-IP, rRNA intermediate analysis, and catalytic mutant validation\",\n      \"pmids\": [\"23175604\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"LAS1L is a component of the Five Friends of Methylated CHTOP (5FMC) nuclear complex, consisting of PELP1, SENP3, WDR18, TEX10, and LAS1L; PELP1 functions as the core scaffold, as other components (including LAS1L) become unstable in its absence; the complex is recruited to CHTOP only when CHTOP is arginine-methylated by PRMT1, linking arginine methylation to desumoylation of transcriptional targets.\",\n      \"method\": \"Biotinylation-proteomics pulldown, Co-IP, siRNA knockdown stability assays, sumoylation assays\",\n      \"journal\": \"Molecular & cellular proteomics : MCP\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — proteomics-based pulldown with functional follow-up on complex stability, single lab\",\n      \"pmids\": [\"22872859\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"A de novo mutation in LAS1L (p.S477N) causes congenital lethal motor neuron disease; morpholino knockdown of las1l in zebrafish causes early lethality and disruption of muscle and peripheral nerve architecture, partially rescued by wild-type but not mutant human LAS1L RNA, confirming that disruption of 60S ribosomal subunit maturation is the pathogenic mechanism.\",\n      \"method\": \"Exome sequencing, zebrafish morpholino knockdown, RNA rescue experiment\",\n      \"journal\": \"Neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo model with wild-type vs. mutant RNA rescue, single lab\",\n      \"pmids\": [\"24647030\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Human LAS1L and NOL9 form a higher-order endonuclease-kinase complex that catalyzes ITS2 pre-rRNA cleavage and 5'-hydroxyl phosphorylation; a Nol9-encoded nucleolar localization sequence (NoLS) is required for nucleolar transport of the assembled Las1L-Nol9 complex; structural analysis by high-resolution imaging defines their spatial organization within the nucleolar sub-structure linked to late pre-rRNA processing.\",\n      \"method\": \"Co-immunoprecipitation, deletion mapping of NoLS, high-resolution fluorescence imaging, functional rRNA processing assays\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — complex assembly characterized with Co-IP, NoLS functionally mapped, spatial localization determined by imaging, enzymatic activities defined\",\n      \"pmids\": [\"31288032\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Las1 possesses HEPN endoribonuclease domains; both HEPN nuclease motifs (RφXXXH) are required for nuclease activity and fidelity; systematic mutagenesis of individual HEPN motif residues and reconstituted HEPN-HEPN' chimeras showed that both motifs contribute to coordinating RNA in the active site; conformational flexibility between the two HEPN domains is required for proper RNA cleavage.\",\n      \"method\": \"In vitro endoribonuclease assays, systematic mutagenesis of active-site residues, HEPN chimera reconstitution, in vivo yeast complementation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with systematic mutagenesis and in vivo validation, multiple orthogonal approaches\",\n      \"pmids\": [\"32220933\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Depletion of LAS1L (along with PELP1 and NOP2) or inhibition of RNA Pol I induces nucleolar stress that triggers p53-dependent transcriptional programming promoting metabolic remodeling and autophagy (rather than apoptosis) in solid tumor cell lines; blocking autophagy sensitizes cancer cells to RNA Pol I inhibition, placing LAS1L in the nucleolar stress–p53–autophagy axis.\",\n      \"method\": \"siRNA knockdown, RNA Pol I inhibitor (CX-5461), gene expression analysis, autophagy assays, cell death/cell cycle assays\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional knockdown with defined pathway placement using multiple molecular tools, single lab\",\n      \"pmids\": [\"34319761\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"LAS1L protein expression is elevated in triple-negative breast cancer (TNBC); β-catenin inhibition decreases LAS1L abundance in the nucleolus; LAS1L functionally enables mammary tumor growth in xenograft models and invasive attributes of TNBC cells, placing LAS1L downstream of β-catenin signaling in TNBC.\",\n      \"method\": \"Nucleolar proteomics, β-catenin inhibitor treatment, xenograft tumor growth assays, invasion assays\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — proteomics plus functional in vivo xenograft validation, single lab\",\n      \"pmids\": [\"33664239\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"hnRNPA1 directly binds two specific intronic sites (UAGGGU and UGGGGU) of LAS1L pre-mRNA to inhibit splicing of LAS1L exon 9; knockdown of hnRNPA1 shifts the LAS1L-L/LAS1L-S isoform ratio and promotes migration, invasion, and EMT in lung cancer cells, establishing hnRNPA1 as a regulator of LAS1L alternative splicing.\",\n      \"method\": \"RNA immunoprecipitation (RIP), RNA pulldown, AGE splicing assays, Transwell migration/invasion assays\",\n      \"journal\": \"Frontiers in oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct RNA-protein binding confirmed by RIP and pulldown, functional consequence measured, single lab\",\n      \"pmids\": [\"35814393\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The nucleolar deubiquitinase USP36 interacts with both LAS1L and NOL9, stabilizes them via deubiquitination, and mediates SUMOylation of LAS1L at lysine 565 (K565); the K565R mutation abolishes LAS1L function in ITS2 pre-rRNA processing without affecting LAS1L stability or Las1L-Nol9 complex formation, demonstrating that USP36-mediated LAS1L SUMOylation is specifically required for ITS2 cleavage.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination/SUMOylation assays, site-directed mutagenesis (K565R), ITS2 processing rescue assays (knockdown + re-expression of WT vs. mutant)\",\n      \"journal\": \"Cancer research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — site-specific mutagenesis separates SUMOylation from complex formation, functional rescue assay validates the modification's role in catalysis, multiple orthogonal biochemical approaches\",\n      \"pmids\": [\"39356143\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cryo-EM structures of human PELP1-WDR18-TEX10 and LAS1L-NOL9 complexes, plus a lower-resolution model of PELP1-WDR18-LAS1L, reveal that LAS1L is recruited to the rixosome core scaffold (PELP1-WDR18-TEX10-LAS1L) via an interaction between the C-terminal helix of WDR18 and the helical domain of LAS1L; truncation of the WDR18 C-terminal helix abolishes LAS1L binding; TEX10 contacts WDR18 at two separate regions, both required for binding.\",\n      \"method\": \"Cryo-EM structure determination, mutagenesis (truncation and point mutations of WDR18-TEX10 interfaces), biochemical binding assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structures with mutagenesis validation of key interfaces, multiple orthogonal structural and biochemical methods in single rigorous study\",\n      \"pmids\": [\"40195365\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"LAS1L is an essential nucleolar HEPN endoribonuclease that, as part of the rixosome complex (with PELP1, WDR18, TEX10, NOL9, and SENP3), cleaves ITS2 of pre-rRNA and partners with the NOL9 polynucleotide kinase to phosphorylate the cleavage product, driving 60S ribosomal subunit maturation; its nucleolar localization depends on a Nol9-encoded localization sequence, its activity requires both HEPN motifs acting together, and its function is regulated by USP36-mediated deubiquitination and SUMOylation at K565, while SUMO-controlled nucleolar partitioning of the complex coordinates ribosome biogenesis rate; loss of LAS1L function triggers p53-dependent G1 arrest and nucleolar stress-induced autophagy.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"LAS1L is an essential nucleolar factor that drives maturation of the 60S large ribosomal subunit by catalyzing cleavage of the ITS2 spacer within pre-rRNA, and its depletion blocks 28S rRNA synthesis and triggers p53-dependent G1 arrest [#0]. It executes this step as the endoribonuclease of a HEPN-domain enzyme: both R\\u03c6XXXH HEPN motifs and conformational flexibility between the two HEPN domains are required to coordinate RNA in the active site and achieve faithful cleavage [#7]. LAS1L partners with the NOL9 polynucleotide kinase to form a higher-order endonuclease\\u2013kinase complex that cleaves ITS2 and phosphorylates the resulting 5'-hydroxyl product, with a NOL9-encoded nucleolar localization sequence directing the assembled complex into the nucleolus [#3, #6]. LAS1L is integrated into a larger nucleolar complex (the mammalian Rix1/rixosome) with PELP1, TEX10, WDR18, NOL9, and SENP3 that co-fractionates with pre-60S particles, where it is recruited to the PELP1-WDR18-TEX10 scaffold through an interface between the WDR18 C-terminal helix and the LAS1L helical domain [#1, #12]. Two post-translational modification systems govern LAS1L activity and complex behavior: SUMO conjugation balanced by the SENP3 protease controls nucleolar partitioning of the complex and the rate of ribosome formation [#2], while the deubiquitinase USP36 stabilizes LAS1L and mediates its SUMOylation at K565, a modification specifically required for ITS2 cleavage but dispensable for complex assembly [#11]. A de novo LAS1L mutation (p.S477N) causes congenital lethal motor neuron disease through disrupted 60S maturation [#5]. Beyond ribosome biogenesis, loss of LAS1L produces nucleolar stress that engages a p53-dependent autophagy program, and LAS1L supports tumor growth in breast and lung cancer contexts [#8, #9].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established that LAS1L is a nucleolar protein essential for large-subunit ribosome biogenesis, answering whether it has a defined functional role rather than being merely nucleolus-localized.\",\n      \"evidence\": \"siRNA knockdown with Northern blot rRNA processing assays, flow cytometry, and p53 pathway analysis in human cells\",\n      \"pmids\": [\"20647540\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the molecular activity of LAS1L itself\", \"Did not identify protein partners or the specific processing step\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Defined the multiprotein context of LAS1L by placing it in a nucleolar complex with PELP1, TEX10, WDR18, NOL9, and SENP3 acting at ITS2 processing, moving from a single protein to a functional module.\",\n      \"evidence\": \"Reciprocal Co-IP, sucrose gradient fractionation, siRNA knockdown with rRNA processing assays, and immunofluorescence\",\n      \"pmids\": [\"22190735\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not assign catalytic roles to individual subunits\", \"Mechanism of nucleolar recruitment not resolved at the structural level\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showed that SUMO conjugation/deconjugation controlled by SENP3 governs nucleolar partitioning of the LAS1L-containing complex, explaining how ribosome formation rate is regulated.\",\n      \"evidence\": \"Biochemical purification, SUMO modification assays, SENP3 depletion, and subcellular fractionation\",\n      \"pmids\": [\"21326211\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"SUMO acceptor site on LAS1L not mapped here\", \"Causal link between SUMO state and catalytic step not established\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Yeast ortholog work revealed that Las1 associates with pre-60S particles and the Grc3 polynucleotide kinase, whose kinase activity is needed for ITS2 processing, establishing the conserved endonuclease-kinase partnership.\",\n      \"evidence\": \"Co-IP, sucrose gradient sedimentation, Northern blot, and kinase-dead Grc3 mutant analysis in S. cerevisiae\",\n      \"pmids\": [\"23175604\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not demonstrate LAS1L's own nuclease activity directly\", \"Catalytic mechanism of cleavage unresolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identified the same subunits as the 5FMC complex recruited to arginine-methylated CHTOP, with PELP1 as the stabilizing scaffold, broadening the complex's role beyond rRNA processing to methylation-linked desumoylation.\",\n      \"evidence\": \"Biotinylation-proteomics pulldown, Co-IP, knockdown stability assays, and sumoylation assays\",\n      \"pmids\": [\"22872859\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab proteomics, the CHTOP link not independently validated\", \"Direct role of LAS1L in this function not isolated\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Linked LAS1L to human disease by showing a de novo p.S477N mutation causes congenital lethal motor neuron disease via impaired 60S maturation.\",\n      \"evidence\": \"Exome sequencing plus zebrafish morpholino knockdown with wild-type vs. mutant RNA rescue\",\n      \"pmids\": [\"24647030\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single family/single lab\", \"Molecular effect of S477N on catalysis or complex assembly not defined\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Reconstituted the human LAS1L-NOL9 endonuclease-kinase complex and showed a NOL9-encoded NoLS directs its nucleolar transport, defining the spatial logic of late pre-rRNA processing.\",\n      \"evidence\": \"Co-IP, deletion mapping of the NoLS, high-resolution fluorescence imaging, and rRNA processing assays\",\n      \"pmids\": [\"31288032\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic structure of the active site not yet determined\", \"How the complex docks onto pre-60S not resolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined LAS1L's catalytic mechanism by showing both HEPN motifs and inter-domain flexibility are required for faithful RNA cleavage, identifying it as the endoribonuclease.\",\n      \"evidence\": \"In vitro endoribonuclease assays, systematic active-site mutagenesis, HEPN chimera reconstitution, and yeast complementation\",\n      \"pmids\": [\"32220933\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mostly yeast/orthologous system\", \"Precise RNA substrate recognition determinants not fully mapped\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Placed LAS1L in a nucleolar stress\\u2013p53\\u2013autophagy axis, showing its loss drives metabolic remodeling and autophagy rather than apoptosis in tumor cells.\",\n      \"evidence\": \"siRNA knockdown, RNA Pol I inhibition (CX-5461), gene expression and autophagy assays in solid tumor lines\",\n      \"pmids\": [\"34319761\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Mechanism distinguishing autophagy from apoptosis downstream of p53 not detailed\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Connected LAS1L to oncogenic signaling by showing it is elevated in TNBC downstream of \\u03b2-catenin and supports tumor growth and invasion.\",\n      \"evidence\": \"Nucleolar proteomics, \\u03b2-catenin inhibitor treatment, xenograft growth and invasion assays\",\n      \"pmids\": [\"33664239\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Whether the tumor phenotype reflects ribosome biogenesis or a separate activity not resolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified hnRNPA1 as a direct regulator of LAS1L alternative splicing, showing it binds intronic sites to control exon 9 inclusion and the LAS1L-L/S isoform ratio in cancer.\",\n      \"evidence\": \"RNA immunoprecipitation, RNA pulldown, splicing assays, and Transwell migration/invasion assays in lung cancer cells\",\n      \"pmids\": [\"35814393\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Functional difference between LAS1L-L and LAS1L-S isoforms in ribosome biogenesis not established\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Resolved a regulatory mechanism by showing USP36 stabilizes LAS1L and mediates K565 SUMOylation specifically required for ITS2 cleavage, decoupling this modification from complex assembly.\",\n      \"evidence\": \"Co-IP, ubiquitination/SUMOylation assays, K565R mutagenesis, and ITS2 processing rescue with WT vs. mutant re-expression\",\n      \"pmids\": [\"39356143\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How K565 SUMOylation alters catalysis mechanistically not shown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Provided the structural basis for rixosome assembly, showing LAS1L is recruited via the WDR18 C-terminal helix contacting its helical domain, explaining how the endonuclease is integrated into the scaffold.\",\n      \"evidence\": \"Cryo-EM of PELP1-WDR18-TEX10 and LAS1L-NOL9, plus mutagenesis of interface residues and binding assays\",\n      \"pmids\": [\"40195365\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full assembled rixosome with bound pre-60S not captured\", \"Conformational coupling between scaffold binding and catalysis unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How LAS1L catalysis is conformationally coupled to scaffold recruitment, SUMOylation state, and pre-60S substrate engagement within the intact nucleolar particle remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structure of the complete rixosome bound to pre-rRNA substrate\", \"Mechanistic link between K565 SUMOylation and HEPN active-site activity not defined\", \"Functional distinction between LAS1L splice isoforms unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [3, 6, 7, 11]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [3, 7]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [6, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [0, 1, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0, 1, 3, 6]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"complexes\": [\"rixosome (mammalian Rix1 complex)\", \"5FMC complex\", \"LAS1L-NOL9 endonuclease-kinase complex\"],\n    \"partners\": [\"NOL9\", \"PELP1\", \"WDR18\", \"TEX10\", \"SENP3\", \"USP36\", \"CHTOP\", \"hnRNPA1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}