{"gene":"RPP14","run_date":"2026-06-10T07:46:27","timeline":{"discoveries":[{"year":1999,"finding":"RPP14 (Rpp14) is a protein subunit of human RNase P that co-purifies with catalytically active RNase P; polyclonal antibodies against recombinant Rpp14 precipitate active RNase P holoenzyme from HeLa cells.","method":"cDNA cloning, immunoprecipitation of catalytically active RNase P with anti-Rpp14 antibodies","journal":"RNA (New York, N.Y.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal immunoprecipitation of active enzyme, single lab, two orthogonal methods (biochemical + immunological)","pmids":["10024167"],"is_preprint":false},{"year":1999,"finding":"Rpp14 localizes to the dense fibrillar component of the nucleolus, but unlike Rpp29 and Rpp38, it lacks an autonomous subnucleolar localization domain and appears to reach the nucleolus via a piggyback mechanism dependent on other RNase P subunits.","method":"Immunofluorescence microscopy, reporter protein localization assays in tissue-culture cells, biochemical fractionation","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization experiment with functional consequence (piggyback dependence), single lab, multiple imaging and biochemical methods","pmids":["10444065"],"is_preprint":false},{"year":2001,"finding":"Rpp14 has strong protein-protein interactions with non-RNase P proteins encoded in a HeLa cell cDNA library, as identified by yeast two-hybrid screening, suggesting it has interaction partners outside the core RNase P complex.","method":"Yeast two-hybrid system with HeLa cell cDNA library","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single method (yeast two-hybrid), no biochemical validation of specific Rpp14 partner reported in this abstract","pmids":["11158571"],"is_preprint":false},{"year":2002,"finding":"Rpp14, together with its interacting partner OIP2, possesses 3'→5' exoribonuclease activity with a phosphorolytic mechanism that processes the 3' terminus of precursor tRNA; immunoprecipitates of crude RNase P complex can process both 5' and 3' ends of pre-tRNA, but purified RNase P alone lacks this exonuclease activity, indicating Rpp14/OIP2 may function as part of an exosome-like activity.","method":"In vitro exoribonuclease assay with recombinant proteins, immunoprecipitation of RNase P complex, substrate (pre-tRNA) processing assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro biochemical reconstitution of enzymatic activity with defined substrates, single lab but multiple orthogonal assays (immunoprecipitation + in vitro activity + purified RNase P negative control)","pmids":["11929972"],"is_preprint":false},{"year":2004,"finding":"Rpp14 participates in direct protein-protein interactions with multiple other subunits of the human RNase MRP/RNase P complexes, as determined by GST pull-down experiments; specific pairwise interactions between Rpp14 and other Rpp subunits were identified, contributing to a structural model of RNase MRP assembly.","method":"GST pull-down assays mapping pairwise protein-protein and protein-RNA interactions among RNase MRP/P subunits","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — GST pull-down (single method) but tested systematically across 10 subunits with multiple pairwise combinations, single lab","pmids":["15096576"],"is_preprint":false},{"year":2006,"finding":"Rpp14 preferentially associates with RNase P rather than RNase MRP; coimmunoprecipitation with VSV-tagged subunits showed that Rpp14 co-sediments with RNase P RNA in 12S fractions and is not substantially found in RNase MRP complexes.","method":"Glycerol gradient sedimentation and coimmunoprecipitation with VSV-epitope-tagged subunits","journal":"RNA (New York, N.Y.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two orthogonal methods (sedimentation + coIP), single lab","pmids":["16723659"],"is_preprint":false},{"year":2007,"finding":"The RPP14 transcript in humans is bicistronic: it encodes both the RPP14 subunit of RNase P and, in a second 3' open reading frame, a mitochondrial 3-hydroxyacyl-thioester dehydratase (HsHTD2) involved in mitochondrial fatty acid synthesis. The HsHTD2 protein was localized to mitochondria and the recombinant enzyme showed (3R)-specific hydratase 2 activity. This bicistronic arrangement is conserved in vertebrates from fish to humans (~400 million years).","method":"cDNA library rescue of yeast htd2 mutant, sequence analysis, mitochondrial localization by microscopy/fractionation, in vitro hydratase activity assay with recombinant protein","journal":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — functional complementation in yeast, enzymatic activity reconstitution in vitro, subcellular localization, and evolutionary conservation all established in one study","pmids":["17898086"],"is_preprint":false},{"year":2017,"finding":"Rpp14 is NOT recruited to laser-microirradiated (DNA damage) sites, in contrast to RNase P subunits Rpp29 and Rpp21, establishing that Rpp14 does not participate in the double-strand break repair function attributed to those subunits.","method":"Live-cell laser microirradiation and fluorescence imaging (negative result for Rpp14 recruitment)","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct live-cell imaging experiment, single lab; negative result for Rpp14 specifically established by the same method that yielded positive results for Rpp29/Rpp21","pmids":["28432356"],"is_preprint":false},{"year":2023,"finding":"Rpp14 carries a 3'→5' exoribonucleolytic activity within the RNase P holoenzyme that degrades the excised 5' leader sequence of precursor tRNA after endonucleolytic cleavage; this activity is magnesium ion-dependent and processive, and is not present in reconstituted or purified RNase P lacking Rpp14. Knockdown of Rpp14 by RNAi broadly inhibits cleavage of flanking and intervening sequences of multiple pre-tRNA species in extracts and in cells, indicating Rpp14 controls tRNA splicing complex and RNase Z for ordered tRNA maturation.","method":"Biochemical assays (exonuclease activity with purified/reconstituted complexes), reverse genetic analysis (RNAi knockdown), in-cell and in-extract pre-tRNA processing assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro biochemical reconstitution plus mutagenesis-level reverse genetics plus in-cell functional assays, all in one rigorous study establishing catalytic mechanism and pathway position","pmids":["37831743"],"is_preprint":false}],"current_model":"RPP14 is a subunit of human nuclear RNase P that localizes to the dense fibrillar component of the nucleolus via a piggyback mechanism; it harbors an intrinsic Mg²⁺-dependent, processive 3'→5' exoribonuclease activity that degrades the excised 5' leader of pre-tRNA and, together with its partner OIP2, processes the 3' terminus of pre-tRNA, while its knockdown broadly inhibits ordered pre-tRNA maturation in cells; the RPP14 transcript is also bicistronic, encoding a second mitochondrial 3-hydroxyacyl-thioester dehydratase (HsHTD2) in a vertebrate-conserved arrangement linking RNA processing to mitochondrial fatty acid synthesis."},"narrative":{"mechanistic_narrative":"RPP14 (Rpp14) is a protein subunit of human nuclear RNase P that participates in precursor tRNA maturation [PMID:10024167, PMID:37831743]. It co-purifies with catalytically active RNase P holoenzyme and engages in direct pairwise protein-protein contacts with other Rpp subunits of the RNase MRP/P system, preferentially partitioning into RNase P rather than RNase MRP complexes [PMID:10024167, PMID:15096576, PMID:16723659]. Within the holoenzyme, Rpp14 contributes an intrinsic, Mg²⁺-dependent and processive 3'→5' exoribonuclease activity that degrades the excised 5' leader of pre-tRNA following endonucleolytic cleavage; this activity is absent from RNase P reconstituted or purified without Rpp14, and its depletion broadly impairs ordered cleavage of flanking and intervening pre-tRNA sequences in cells and extracts [PMID:11929972, PMID:37831743]. Together with its partner OIP2, Rpp14 also processes the 3' terminus of pre-tRNA through a phosphorolytic exonucleolytic mechanism [PMID:11929972]. Rpp14 localizes to the dense fibrillar component of the nucleolus, reaching this compartment by a piggyback mechanism dependent on other RNase P subunits rather than an autonomous targeting domain [PMID:10444065]. Unlike the Rpp29 and Rpp21 subunits, Rpp14 is not recruited to DNA double-strand break sites, distinguishing it from the DNA-repair role of those subunits [PMID:28432356]. Independently, the human RPP14 transcript is bicistronic: a second 3' open reading frame encodes a mitochondrial 3-hydroxyacyl-thioester dehydratase (HsHTD2) with (3R)-specific hydratase 2 activity in mitochondrial fatty acid synthesis, an arrangement conserved across vertebrates [PMID:17898086].","teleology":[{"year":1999,"claim":"Establishing that Rpp14 is a bona fide subunit of human RNase P answered whether this cloned protein is physically and functionally part of the tRNA-processing enzyme.","evidence":"cDNA cloning and immunoprecipitation of catalytically active RNase P with anti-Rpp14 antibodies in HeLa cells","pmids":["10024167"],"confidence":"Medium","gaps":["Does not define Rpp14's catalytic or structural contribution within the complex","Single lab; reciprocal but not structurally resolved"]},{"year":1999,"claim":"Defining how Rpp14 reaches the nucleolus showed it lacks autonomous subnucleolar targeting and depends on other subunits, framing it as an assembly-dependent rather than independently localizing component.","evidence":"Immunofluorescence, reporter localization assays, and biochemical fractionation in tissue-culture cells","pmids":["10444065"],"confidence":"Medium","gaps":["The specific subunit(s) mediating piggyback transport not identified","No structural basis for the targeting dependence"]},{"year":2001,"claim":"A two-hybrid screen raised the possibility that Rpp14 has interaction partners beyond the core RNase P complex, hinting at functions outside the holoenzyme.","evidence":"Yeast two-hybrid screening against a HeLa cDNA library","pmids":["11158571"],"confidence":"Low","gaps":["Single method without biochemical validation of specific partners","No functional consequence established for any extra-complex interaction"]},{"year":2002,"claim":"Identifying a 3' exoribonuclease activity for Rpp14 with its partner OIP2 answered whether Rpp14 contributes catalysis beyond the endonucleolytic core, linking it to 3'-end pre-tRNA processing.","evidence":"In vitro exoribonuclease and pre-tRNA processing assays with recombinant proteins plus immunoprecipitation of crude vs purified RNase P (negative control)","pmids":["11929972"],"confidence":"High","gaps":["Whether the activity is intrinsic to Rpp14 or to OIP2 not resolved here","Phosphorolytic exosome-like assignment relies on crude complex behavior"]},{"year":2004,"claim":"Mapping pairwise interactions positioned Rpp14 within an assembly model of the RNase MRP/P subunit network, establishing its direct structural contacts.","evidence":"GST pull-down assays across multiple Rpp subunit combinations","pmids":["15096576"],"confidence":"Medium","gaps":["Single interaction method without stoichiometry or structure","Does not distinguish RNase P from RNase MRP context"]},{"year":2006,"claim":"Showing preferential association with RNase P over RNase MRP clarified which complex Rpp14 predominantly functions in.","evidence":"Glycerol gradient sedimentation and coimmunoprecipitation with VSV-tagged subunits","pmids":["16723659"],"confidence":"Medium","gaps":["Does not exclude minor or transient RNase MRP association","No functional readout of the partitioning"]},{"year":2007,"claim":"Discovery that the RPP14 transcript is bicistronic answered an unexpected question of gene organization, assigning a second mitochondrial fatty-acid-synthesis enzyme (HsHTD2) to the same mRNA.","evidence":"Yeast htd2-mutant complementation, sequence/conservation analysis, mitochondrial localization, and in vitro (3R)-hydratase activity assay","pmids":["17898086"],"confidence":"High","gaps":["Mechanism of translation of the second ORF not detailed","Functional coupling, if any, between RNA processing and mitochondrial fatty acid synthesis unknown"]},{"year":2017,"claim":"A negative recruitment result distinguished Rpp14 from Rpp29/Rpp21, establishing it does not participate in the RNase P-linked DNA double-strand break repair function.","evidence":"Live-cell laser microirradiation and fluorescence imaging (negative for Rpp14)","pmids":["28432356"],"confidence":"Medium","gaps":["Negative imaging result does not exclude indirect DNA-damage roles","Single assay and cell context"]},{"year":2023,"claim":"Defining Rpp14 as the carrier of a Mg²⁺-dependent processive 3'→5' exonuclease that degrades the excised 5' pre-tRNA leader, and showing its knockdown disrupts ordered maturation, fixed Rpp14's catalytic role and its position in the tRNA processing pathway.","evidence":"Exonuclease assays with purified/reconstituted complexes, RNAi knockdown, and in-cell/in-extract pre-tRNA processing assays","pmids":["37831743"],"confidence":"High","gaps":["Atomic-resolution structure of the active site not determined","Mechanistic coordination with the tRNA splicing complex and RNase Z not fully resolved"]},{"year":null,"claim":"How Rpp14's exoribonuclease activity is structurally integrated with the RNase P endonucleolytic core and coordinated with downstream RNase Z and the tRNA splicing machinery remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No high-resolution structure of Rpp14 within active RNase P","Mechanism coupling leader degradation to ordered tRNA maturation incompletely defined","Functional significance of extra-complex interactions and the bicistronic HsHTD2 ORF unconnected to RNase P function"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[3,8]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[3,8,6]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,4]}],"localization":[{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[1]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[6]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[3,8]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[6]}],"complexes":["RNase P","RNase MRP"],"partners":["OIP2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O95059","full_name":"Ribonuclease P protein subunit p14","aliases":[],"length_aa":124,"mass_kda":13.7,"function":"Component of ribonuclease P, a ribonucleoprotein complex that generates mature tRNA molecules by cleaving their 5'-ends","subcellular_location":"Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/O95059/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/RPP14","classification":"Common Essential","n_dependent_lines":1167,"n_total_lines":1208,"dependency_fraction":0.9660596026490066},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"RPP30","stoichiometry":4.0},{"gene":"SSB","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/RPP14","total_profiled":1310},"omim":[{"mim_id":"620769","title":"HYDROXYACYL-THIOESTER DEHYDRATASE, TYPE 2; HTD2","url":"https://www.omim.org/entry/620769"},{"mim_id":"606117","title":"RIBONUCLEASE P/MRP SUBUNIT p40; RPP40","url":"https://www.omim.org/entry/606117"},{"mim_id":"606116","title":"RIBONUCLEASE P/MRP SUBUNIT p38; RPP38","url":"https://www.omim.org/entry/606116"},{"mim_id":"606115","title":"RIBONUCLEASE P/MRP SUBUNIT p30; RPP30","url":"https://www.omim.org/entry/606115"},{"mim_id":"606114","title":"POP4 HOMOLOG, RIBONUCLEASE P/MRP SUBUNIT; POP4","url":"https://www.omim.org/entry/606114"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"skeletal muscle","ntpm":38.1},{"tissue":"tongue","ntpm":36.4}],"url":"https://www.proteinatlas.org/search/RPP14"},"hgnc":{"alias_symbol":["P14"],"prev_symbol":[]},"alphafold":{"accession":"O95059","domains":[{"cath_id":"3.30.70.3250","chopping":"32-107","consensus_level":"high","plddt":85.1018,"start":32,"end":107}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95059","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95059-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95059-F1-predicted_aligned_error_v6.png","plddt_mean":79.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RPP14","jax_strain_url":"https://www.jax.org/strain/search?query=RPP14"},"sequence":{"accession":"O95059","fasta_url":"https://rest.uniprot.org/uniprotkb/O95059.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95059/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95059"}},"corpus_meta":[{"pmid":"19028688","id":"PMC_19028688","title":"Mitochondrial 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of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/11158571","citation_count":51,"is_preprint":false},{"pmid":"10024167","id":"PMC_10024167","title":"Rpp14 and Rpp29, two protein subunits of human ribonuclease P.","date":"1999","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/10024167","citation_count":48,"is_preprint":false},{"pmid":"12003489","id":"PMC_12003489","title":"Purification and characterization of Rpp25, an RNA-binding protein subunit of human ribonuclease P.","date":"2002","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/12003489","citation_count":47,"is_preprint":false},{"pmid":"16723659","id":"PMC_16723659","title":"Differential association of protein subunits with the human RNase MRP and RNase P complexes.","date":"2006","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/16723659","citation_count":44,"is_preprint":false},{"pmid":"28432356","id":"PMC_28432356","title":"A role of human 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\"journal\": \"RNA (New York, N.Y.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal immunoprecipitation of active enzyme, single lab, two orthogonal methods (biochemical + immunological)\",\n      \"pmids\": [\"10024167\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Rpp14 localizes to the dense fibrillar component of the nucleolus, but unlike Rpp29 and Rpp38, it lacks an autonomous subnucleolar localization domain and appears to reach the nucleolus via a piggyback mechanism dependent on other RNase P subunits.\",\n      \"method\": \"Immunofluorescence microscopy, reporter protein localization assays in tissue-culture cells, biochemical fractionation\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment with functional consequence (piggyback dependence), single lab, multiple imaging and biochemical methods\",\n      \"pmids\": [\"10444065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Rpp14 has strong protein-protein interactions with non-RNase P proteins encoded in a HeLa cell cDNA library, as identified by yeast two-hybrid screening, suggesting it has interaction partners outside the core RNase P complex.\",\n      \"method\": \"Yeast two-hybrid system with HeLa cell cDNA library\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single method (yeast two-hybrid), no biochemical validation of specific Rpp14 partner reported in this abstract\",\n      \"pmids\": [\"11158571\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Rpp14, together with its interacting partner OIP2, possesses 3'→5' exoribonuclease activity with a phosphorolytic mechanism that processes the 3' terminus of precursor tRNA; immunoprecipitates of crude RNase P complex can process both 5' and 3' ends of pre-tRNA, but purified RNase P alone lacks this exonuclease activity, indicating Rpp14/OIP2 may function as part of an exosome-like activity.\",\n      \"method\": \"In vitro exoribonuclease assay with recombinant proteins, immunoprecipitation of RNase P complex, substrate (pre-tRNA) processing assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro biochemical reconstitution of enzymatic activity with defined substrates, single lab but multiple orthogonal assays (immunoprecipitation + in vitro activity + purified RNase P negative control)\",\n      \"pmids\": [\"11929972\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Rpp14 participates in direct protein-protein interactions with multiple other subunits of the human RNase MRP/RNase P complexes, as determined by GST pull-down experiments; specific pairwise interactions between Rpp14 and other Rpp subunits were identified, contributing to a structural model of RNase MRP assembly.\",\n      \"method\": \"GST pull-down assays mapping pairwise protein-protein and protein-RNA interactions among RNase MRP/P subunits\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — GST pull-down (single method) but tested systematically across 10 subunits with multiple pairwise combinations, single lab\",\n      \"pmids\": [\"15096576\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Rpp14 preferentially associates with RNase P rather than RNase MRP; coimmunoprecipitation with VSV-tagged subunits showed that Rpp14 co-sediments with RNase P RNA in 12S fractions and is not substantially found in RNase MRP complexes.\",\n      \"method\": \"Glycerol gradient sedimentation and coimmunoprecipitation with VSV-epitope-tagged subunits\",\n      \"journal\": \"RNA (New York, N.Y.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two orthogonal methods (sedimentation + coIP), single lab\",\n      \"pmids\": [\"16723659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"The RPP14 transcript in humans is bicistronic: it encodes both the RPP14 subunit of RNase P and, in a second 3' open reading frame, a mitochondrial 3-hydroxyacyl-thioester dehydratase (HsHTD2) involved in mitochondrial fatty acid synthesis. The HsHTD2 protein was localized to mitochondria and the recombinant enzyme showed (3R)-specific hydratase 2 activity. This bicistronic arrangement is conserved in vertebrates from fish to humans (~400 million years).\",\n      \"method\": \"cDNA library rescue of yeast htd2 mutant, sequence analysis, mitochondrial localization by microscopy/fractionation, in vitro hydratase activity assay with recombinant protein\",\n      \"journal\": \"FASEB journal : official publication of the Federation of American Societies for Experimental Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — functional complementation in yeast, enzymatic activity reconstitution in vitro, subcellular localization, and evolutionary conservation all established in one study\",\n      \"pmids\": [\"17898086\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Rpp14 is NOT recruited to laser-microirradiated (DNA damage) sites, in contrast to RNase P subunits Rpp29 and Rpp21, establishing that Rpp14 does not participate in the double-strand break repair function attributed to those subunits.\",\n      \"method\": \"Live-cell laser microirradiation and fluorescence imaging (negative result for Rpp14 recruitment)\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct live-cell imaging experiment, single lab; negative result for Rpp14 specifically established by the same method that yielded positive results for Rpp29/Rpp21\",\n      \"pmids\": [\"28432356\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Rpp14 carries a 3'→5' exoribonucleolytic activity within the RNase P holoenzyme that degrades the excised 5' leader sequence of precursor tRNA after endonucleolytic cleavage; this activity is magnesium ion-dependent and processive, and is not present in reconstituted or purified RNase P lacking Rpp14. Knockdown of Rpp14 by RNAi broadly inhibits cleavage of flanking and intervening sequences of multiple pre-tRNA species in extracts and in cells, indicating Rpp14 controls tRNA splicing complex and RNase Z for ordered tRNA maturation.\",\n      \"method\": \"Biochemical assays (exonuclease activity with purified/reconstituted complexes), reverse genetic analysis (RNAi knockdown), in-cell and in-extract pre-tRNA processing assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro biochemical reconstitution plus mutagenesis-level reverse genetics plus in-cell functional assays, all in one rigorous study establishing catalytic mechanism and pathway position\",\n      \"pmids\": [\"37831743\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RPP14 is a subunit of human nuclear RNase P that localizes to the dense fibrillar component of the nucleolus via a piggyback mechanism; it harbors an intrinsic Mg²⁺-dependent, processive 3'→5' exoribonuclease activity that degrades the excised 5' leader of pre-tRNA and, together with its partner OIP2, processes the 3' terminus of pre-tRNA, while its knockdown broadly inhibits ordered pre-tRNA maturation in cells; the RPP14 transcript is also bicistronic, encoding a second mitochondrial 3-hydroxyacyl-thioester dehydratase (HsHTD2) in a vertebrate-conserved arrangement linking RNA processing to mitochondrial fatty acid synthesis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RPP14 (Rpp14) is a protein subunit of human nuclear RNase P that participates in precursor tRNA maturation [#0, #8]. It co-purifies with catalytically active RNase P holoenzyme and engages in direct pairwise protein-protein contacts with other Rpp subunits of the RNase MRP/P system, preferentially partitioning into RNase P rather than RNase MRP complexes [#0, #4, #5]. Within the holoenzyme, Rpp14 contributes an intrinsic, Mg\\u00b2\\u207a-dependent and processive 3'\\u21925' exoribonuclease activity that degrades the excised 5' leader of pre-tRNA following endonucleolytic cleavage; this activity is absent from RNase P reconstituted or purified without Rpp14, and its depletion broadly impairs ordered cleavage of flanking and intervening pre-tRNA sequences in cells and extracts [#3, #8]. Together with its partner OIP2, Rpp14 also processes the 3' terminus of pre-tRNA through a phosphorolytic exonucleolytic mechanism [#3]. Rpp14 localizes to the dense fibrillar component of the nucleolus, reaching this compartment by a piggyback mechanism dependent on other RNase P subunits rather than an autonomous targeting domain [#1]. Unlike the Rpp29 and Rpp21 subunits, Rpp14 is not recruited to DNA double-strand break sites, distinguishing it from the DNA-repair role of those subunits [#7]. Independently, the human RPP14 transcript is bicistronic: a second 3' open reading frame encodes a mitochondrial 3-hydroxyacyl-thioester dehydratase (HsHTD2) with (3R)-specific hydratase 2 activity in mitochondrial fatty acid synthesis, an arrangement conserved across vertebrates [#6].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Establishing that Rpp14 is a bona fide subunit of human RNase P answered whether this cloned protein is physically and functionally part of the tRNA-processing enzyme.\",\n      \"evidence\": \"cDNA cloning and immunoprecipitation of catalytically active RNase P with anti-Rpp14 antibodies in HeLa cells\",\n      \"pmids\": [\"10024167\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not define Rpp14's catalytic or structural contribution within the complex\", \"Single lab; reciprocal but not structurally resolved\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Defining how Rpp14 reaches the nucleolus showed it lacks autonomous subnucleolar targeting and depends on other subunits, framing it as an assembly-dependent rather than independently localizing component.\",\n      \"evidence\": \"Immunofluorescence, reporter localization assays, and biochemical fractionation in tissue-culture cells\",\n      \"pmids\": [\"10444065\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The specific subunit(s) mediating piggyback transport not identified\", \"No structural basis for the targeting dependence\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"A two-hybrid screen raised the possibility that Rpp14 has interaction partners beyond the core RNase P complex, hinting at functions outside the holoenzyme.\",\n      \"evidence\": \"Yeast two-hybrid screening against a HeLa cDNA library\",\n      \"pmids\": [\"11158571\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single method without biochemical validation of specific partners\", \"No functional consequence established for any extra-complex interaction\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Identifying a 3' exoribonuclease activity for Rpp14 with its partner OIP2 answered whether Rpp14 contributes catalysis beyond the endonucleolytic core, linking it to 3'-end pre-tRNA processing.\",\n      \"evidence\": \"In vitro exoribonuclease and pre-tRNA processing assays with recombinant proteins plus immunoprecipitation of crude vs purified RNase P (negative control)\",\n      \"pmids\": [\"11929972\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the activity is intrinsic to Rpp14 or to OIP2 not resolved here\", \"Phosphorolytic exosome-like assignment relies on crude complex behavior\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Mapping pairwise interactions positioned Rpp14 within an assembly model of the RNase MRP/P subunit network, establishing its direct structural contacts.\",\n      \"evidence\": \"GST pull-down assays across multiple Rpp subunit combinations\",\n      \"pmids\": [\"15096576\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single interaction method without stoichiometry or structure\", \"Does not distinguish RNase P from RNase MRP context\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Showing preferential association with RNase P over RNase MRP clarified which complex Rpp14 predominantly functions in.\",\n      \"evidence\": \"Glycerol gradient sedimentation and coimmunoprecipitation with VSV-tagged subunits\",\n      \"pmids\": [\"16723659\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not exclude minor or transient RNase MRP association\", \"No functional readout of the partitioning\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Discovery that the RPP14 transcript is bicistronic answered an unexpected question of gene organization, assigning a second mitochondrial fatty-acid-synthesis enzyme (HsHTD2) to the same mRNA.\",\n      \"evidence\": \"Yeast htd2-mutant complementation, sequence/conservation analysis, mitochondrial localization, and in vitro (3R)-hydratase activity assay\",\n      \"pmids\": [\"17898086\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of translation of the second ORF not detailed\", \"Functional coupling, if any, between RNA processing and mitochondrial fatty acid synthesis unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"A negative recruitment result distinguished Rpp14 from Rpp29/Rpp21, establishing it does not participate in the RNase P-linked DNA double-strand break repair function.\",\n      \"evidence\": \"Live-cell laser microirradiation and fluorescence imaging (negative for Rpp14)\",\n      \"pmids\": [\"28432356\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Negative imaging result does not exclude indirect DNA-damage roles\", \"Single assay and cell context\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defining Rpp14 as the carrier of a Mg\\u00b2\\u207a-dependent processive 3'\\u21925' exonuclease that degrades the excised 5' pre-tRNA leader, and showing its knockdown disrupts ordered maturation, fixed Rpp14's catalytic role and its position in the tRNA processing pathway.\",\n      \"evidence\": \"Exonuclease assays with purified/reconstituted complexes, RNAi knockdown, and in-cell/in-extract pre-tRNA processing assays\",\n      \"pmids\": [\"37831743\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic-resolution structure of the active site not determined\", \"Mechanistic coordination with the tRNA splicing complex and RNase Z not fully resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How Rpp14's exoribonuclease activity is structurally integrated with the RNase P endonucleolytic core and coordinated with downstream RNase Z and the tRNA splicing machinery remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No high-resolution structure of Rpp14 within active RNase P\", \"Mechanism coupling leader degradation to ordered tRNA maturation incompletely defined\", \"Functional significance of extra-complex interactions and the bicistronic HsHTD2 ORF unconnected to RNase P function\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [3, 8]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [3, 8, 6]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [3, 8]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"complexes\": [\"RNase P\", \"RNase MRP\"],\n    \"partners\": [\"OIP2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}