Affinage

RPP14

Ribonuclease P protein subunit p14 · UniProt O95059

Length
124 aa
Mass
13.7 kDa
Annotated
2026-06-10
19 papers in source corpus 9 papers cited in narrative 9 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

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).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 1999 Medium

    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

    PMID:10024167

    Open questions at the time
    • Does not define Rpp14's catalytic or structural contribution within the complex
    • Single lab; reciprocal but not structurally resolved
  2. 1999 Medium

    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

    PMID:10444065

    Open questions at the time
    • The specific subunit(s) mediating piggyback transport not identified
    • No structural basis for the targeting dependence
  3. 2001 Low

    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

    PMID:11158571

    Open questions at the time
    • Single method without biochemical validation of specific partners
    • No functional consequence established for any extra-complex interaction
  4. 2002 High

    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)

    PMID:11929972

    Open questions at the time
    • Whether the activity is intrinsic to Rpp14 or to OIP2 not resolved here
    • Phosphorolytic exosome-like assignment relies on crude complex behavior
  5. 2004 Medium

    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

    PMID:15096576

    Open questions at the time
    • Single interaction method without stoichiometry or structure
    • Does not distinguish RNase P from RNase MRP context
  6. 2006 Medium

    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

    PMID:16723659

    Open questions at the time
    • Does not exclude minor or transient RNase MRP association
    • No functional readout of the partitioning
  7. 2007 High

    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

    PMID:17898086

    Open questions at the time
    • Mechanism of translation of the second ORF not detailed
    • Functional coupling, if any, between RNA processing and mitochondrial fatty acid synthesis unknown
  8. 2017 Medium

    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)

    PMID:28432356

    Open questions at the time
    • Negative imaging result does not exclude indirect DNA-damage roles
    • Single assay and cell context
  9. 2023 High

    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

    PMID:37831743

    Open questions at the time
    • Atomic-resolution structure of the active site not determined
    • Mechanistic coordination with the tRNA splicing complex and RNase Z not fully resolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • 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.
  • 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

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016787 hydrolase activity 3 GO:0005198 structural molecule activity 2 GO:0140098 catalytic activity, acting on RNA 2
Localization
GO:0005730 nucleolus 1 GO:0005739 mitochondrion 1
Pathway
R-HSA-8953854 Metabolism of RNA 2 R-HSA-1430728 Metabolism 1
Partners
OIP2
Complex memberships
RNase MRPRNase P

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1999 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. cDNA cloning, immunoprecipitation of catalytically active RNase P with anti-Rpp14 antibodies RNA (New York, N.Y.) Medium 10024167
1999 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. Immunofluorescence microscopy, reporter protein localization assays in tissue-culture cells, biochemical fractionation The Journal of cell biology Medium 10444065
2001 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. Yeast two-hybrid system with HeLa cell cDNA library Proceedings of the National Academy of Sciences of the United States of America Low 11158571
2002 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. In vitro exoribonuclease assay with recombinant proteins, immunoprecipitation of RNase P complex, substrate (pre-tRNA) processing assays Proceedings of the National Academy of Sciences of the United States of America High 11929972
2004 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. GST pull-down assays mapping pairwise protein-protein and protein-RNA interactions among RNase MRP/P subunits Nucleic acids research Medium 15096576
2006 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. Glycerol gradient sedimentation and coimmunoprecipitation with VSV-epitope-tagged subunits RNA (New York, N.Y.) Medium 16723659
2007 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). cDNA library rescue of yeast htd2 mutant, sequence analysis, mitochondrial localization by microscopy/fractionation, in vitro hydratase activity assay with recombinant protein FASEB journal : official publication of the Federation of American Societies for Experimental Biology High 17898086
2017 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. Live-cell laser microirradiation and fluorescence imaging (negative result for Rpp14 recruitment) Scientific reports Medium 28432356
2023 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. Biochemical assays (exonuclease activity with purified/reconstituted complexes), reverse genetic analysis (RNAi knockdown), in-cell and in-extract pre-tRNA processing assays Proceedings of the National Academy of Sciences of the United States of America High 37831743

Source papers

Stage 0 corpus · 19 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2008 Mitochondrial fatty acid synthesis type II: more than just fatty acids. The Journal of biological chemistry 135 19028688
2004 Mutual interactions between subunits of the human RNase MRP ribonucleoprotein complex. Nucleic acids research 86 15096576
1999 Localization in the nucleolus and coiled bodies of protein subunits of the ribonucleoprotein ribonuclease P. The Journal of cell biology 77 10444065
2009 Mitochondrial fatty acid synthesis--an adopted set of enzymes making a pathway of major importance for the cellular metabolism. Progress in lipid research 66 19686777
2006 Inventory and analysis of the protein subunits of the ribonucleases P and MRP provides further evidence of homology between the yeast and human enzymes. Nucleic acids research 60 16998185
2007 An ancient genetic link between vertebrate mitochondrial fatty acid synthesis and RNA processing. FASEB journal : official publication of the Federation of American Societies for Experimental Biology 52 17898086
2001 Protein-protein interactions with subunits of human nuclear RNase P. Proceedings of the National Academy of Sciences of the United States of America 51 11158571
1999 Rpp14 and Rpp29, two protein subunits of human ribonuclease P. RNA (New York, N.Y.) 48 10024167
2002 Purification and characterization of Rpp25, an RNA-binding protein subunit of human ribonuclease P. RNA (New York, N.Y.) 47 12003489
2006 Differential association of protein subunits with the human RNase MRP and RNase P complexes. RNA (New York, N.Y.) 44 16723659
2017 A role of human RNase P subunits, Rpp29 and Rpp21, in homology directed-repair of double-strand breaks. Scientific reports 26 28432356
2014 PXK locus in systemic lupus erythematosus: fine mapping and functional analysis reveals novel susceptibility gene ABHD6. Annals of the rheumatic diseases 23 24534757
2017 Detecting novel micro RNAs in rheumatoid arthritis with gene-based association testing. Clinical and experimental rheumatology 22 28134081
2002 A protein subunit of human RNase P, Rpp14, and its interacting partner, OIP2, have 3'-->5' exoribonuclease activity. Proceedings of the National Academy of Sciences of the United States of America 19 11929972
2022 Deregulated molecules and pathways in the predisposition and dissemination of breast cancer cells to bone. Computational and structural biotechnology journal 15 35685372
2023 Human RNase P exhibits and controls distinct ribonucleolytic activities required for ordered maturation of tRNA. Proceedings of the National Academy of Sciences of the United States of America 7 37831743
2020 Learning-induced mRNA alterations in olfactory bulb mitral cells in neonatal rats. Learning & memory (Cold Spring Harbor, N.Y.) 3 32295841
1999 [Infiltration of monocytes/macrophages and expression of monocyte chemoattractant protein-1 in gingival tissues from patients with rapidly progressive periodontitis]. Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology 2 11776908
2025 Ribonuclease P/MRP subunit RPP40 coordinates the transcription of pre-rRNA and ribosomal protein genes to promote Hepatocellular carcinoma malignancy. Gene 1 40517827

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