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Showing MRPL12 — MRPL7 is a alias.

MRPL12

Large ribosomal subunit protein bL12m · UniProt P52815

Length
198 aa
Mass
21.3 kDa
Annotated
2026-06-10
15 papers in source corpus 11 papers cited in narrative 11 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

MRPL12 is a mitochondrial large ribosomal subunit protein that couples mitochondrial translation to the regulation of mitochondrial gene expression and metabolic output (PMID:8626705, PMID:23603806). Its N-terminal 49 residues direct mitochondrial targeting, after which it integrates into the large ribosomal subunit; loss of integration or expression of a dominant-negative truncation impairs mitochondrial translation and ATP production (PMID:8626705, PMID:23603806). A patient missense mutation (p.Ala181Val) destabilizes MRPL12, blocks its incorporation into the large subunit, and reduces synthesis of mtDNA-encoded COXI–III, linking MRPL12 directly to a human mitochondrial translation defect (PMID:23603806). Beyond the ribosome, MRPL12 acts as a regulator of mitochondrial transcription by binding the mitochondrial RNA polymerase POLRMT, and this interaction is tuned by post-translational modifications: tyrosine-60 phosphorylation (reversed by the phosphatase UBASH3B) and lysine-163 acetylation (written by TIP60, erased by SIRT5) each promote POLRMT binding and enhance OXPHOS, with these axes driving lung adenocarcinoma and clear-cell renal carcinoma phenotypes respectively (PMID:39343960, PMID:40858596). MRPL12 abundance is further set by ubiquitin-dependent turnover, including CUL3-mediated K63-linked ubiquitination at K150 and ING2-dependent regulation, and its expression is controlled transcriptionally by Nrf2 and by SQSTM1/p62 acting through p38–ATF2, and post-transcriptionally by the m6A reader YTHDC2 (PMID:32805647, PMID:33444714, PMID:34434929, PMID:37526061, PMID:38129673). MRPL12 additionally binds adenine nucleotide translocase ANT3 to stabilize the mitochondrial permeability transition pore, a non-ribosomal function controlling mitochondrial membrane homeostasis and apoptosis (PMID:37182101).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 1996 High

    Established that MRPL12 is a mitochondrial ribosome-associated protein whose function is required for mitochondrial energy production, defining its core cellular role.

    Evidence Immunofluorescence, cell fractionation, in vitro ribosome association, and dominant-negative truncation with ATP readout in human cells

    PMID:8626705

    Open questions at the time
    • Did not resolve the structural position of MRPL12 within the large subunit
    • No identification of direct ribosomal or elongation-factor contacts
  2. 2005 High

    Placed MRPL12 in a growth-control pathway, showing CycD/Cdk4-driven cell growth requires mRpL12-dependent mitochondrial activity acting with Hph.

    Evidence Loss-of-function genetic screen and epistasis with cdk4-null and hph mutants in Drosophila

    PMID:15692573

    Open questions at the time
    • Molecular mechanism linking CycD/Cdk4 to mRpL12 not defined
    • Conservation of the pathway in mammals not tested
  3. 2013 High

    Connected MRPL12 to human disease by showing a missense mutation impairs ribosome integration and mitochondrial translation, demonstrating MRPL12 is required for large-subunit assembly.

    Evidence Patient fibroblast analysis with ribosome fractionation and [35S]-methionine mitochondrial translation labeling

    PMID:23603806

    Open questions at the time
    • Predicted elongation-factor interface at Ala181 not biochemically confirmed
    • Full clinical-genetic causality across families not established
  4. 2020 Medium

    Identified upstream transcriptional control of MRPL12, showing SQSTM1/p62 drives its expression through p38–ATF2 to regulate mtDNA expression under stress.

    Evidence ATF2 promoter binding, p38 inhibition, p62 knockdown/overexpression, and TEC-specific knockout mice

    PMID:32805647

    Open questions at the time
    • Direct ATF2 occupancy not extended beyond renal cells
    • How mtDNA expression mechanistically follows MRPL12 induction not detailed
  5. 2021 Medium

    Expanded the regulatory inputs to MRPL12 by implicating Nrf2 transcriptional control and ING2-dependent ubiquitination in setting MRPL12 levels and OXPHOS.

    Evidence Proteomics, co-immunofluorescence, overexpression rescue (Nrf2); co-IP and OCR assays with ischemic kidney models (ING2)

    PMID:33444714 PMID:34434929

    Open questions at the time
    • Direct Nrf2 binding to the MRPL12 promoter not shown by ChIP
    • ING2 ubiquitin ligase mechanism and target lysines not defined
  6. 2023 Medium

    Defined post-translational and post-transcriptional control of MRPL12 abundance via CUL3-mediated K63 ubiquitination and YTHDC2-mediated mRNA destabilization.

    Evidence Co-IP, K150 site-directed mutagenesis and K63 ubiquitination assays (CUL3); MeRIP and mRNA stability assays with tumor model (YTHDC2)

    PMID:37526061 PMID:38129673

    Open questions at the time
    • Whether K63 ubiquitination signals degradation versus another fate not resolved
    • Findings each from a single lab without reciprocal validation
  7. 2023 Medium

    Revealed a non-ribosomal function for MRPL12 in binding ANT3 to stabilize the permeability transition pore and prevent apoptosis.

    Evidence Reciprocal co-IP, MPTP opening and membrane potential assays, overexpression rescue in H/R model

    PMID:37182101

    Open questions at the time
    • Structural basis of MRPL12-ANT3 binding and its relation to ribosomal pool unknown
    • Single-lab evidence
  8. 2024 Medium

    Showed that MRPL12-POLRMT interaction governing mitochondrial metabolism is controlled by Y60 phosphorylation, reversibly tuned by UBASH3B.

    Evidence MS phosphosite mapping, co-IP for UBASH3B and POLRMT, Y60 mutagenesis, LUAD mouse and patient-derived organoid models

    PMID:39343960

    Open questions at the time
    • Kinase writing Y60 phosphorylation not identified
    • Single-lab evidence
  9. 2025 Medium

    Established a second PTM axis controlling POLRMT binding, with TIP60-mediated K163 acetylation enhancing and SIRT5 reversing mitochondrial biosynthesis in renal cancer.

    Evidence Co-IP identifying TIP60, SIRT5, and POLRMT; K163 mutagenesis; metabolic flux and in vivo ccRCC models

    PMID:40858596

    Open questions at the time
    • Interplay between K163 acetylation and Y60 phosphorylation on POLRMT binding not tested
    • Single-lab evidence

Open questions

Synthesis pass · forward-looking unresolved questions
  • How MRPL12's ribosomal role, its POLRMT-regulatory function, and its ANT3/MPTP role are partitioned within a single protein pool remains unresolved.
  • No structural model integrating ribosomal and transcription-regulatory functions
  • No demonstration of which modification states route MRPL12 to each role

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005198 structural molecule activity 2 GO:0140110 transcription regulator activity 2
Localization
GO:0005840 ribosome 2 GO:0005739 mitochondrion 1
Pathway
R-HSA-1430728 Metabolism 3 R-HSA-8953854 Metabolism of RNA 2
Partners
ANT3CUL3ING2POLRMTSIRT5TIP60UBASH3BYTHDC2
Complex memberships
mitochondrial large ribosomal subunit (mt-LSU)

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1996 MRPL12 protein localizes predominantly to mitochondria (confirmed by immunofluorescence microscopy and cell fractionation), associates with ribosomal structures in vitro, and its NH2-terminal 49 amino acids are necessary and sufficient for mitochondrial targeting. Expression of a dominant-negative truncated MRPL12 severely reduced cell growth by inhibiting mitochondrial ATP production. Immunofluorescence microscopy, cell fractionation, in vitro association assay, dominant-negative truncation overexpression with ATP production readout The Journal of biological chemistry High 8626705
2005 In Drosophila, mRpL12 is required downstream of CycD/Cdk4 for cell growth and mitochondrial activity. Genetic epistasis showed that CycD/Cdk4-stimulated mitochondrial activity is mRpL12-dependent, and that the CycD/Cdk4 effector Hph (HIF-1 prolyl hydroxylase) also requires mRpL12 dosage, placing mRpL12 in a common CycD/Cdk4–mRpL12–Hph pathway controlling growth via mitochondrial activity. Loss-of-function genetic screen in Drosophila eye, homozygous mutant cell analysis, mitochondrial activity assays, genetic epistasis with cdk4 null and hph mutants The EMBO journal High 15692573
2013 A missense mutation p.Ala181Val in MRPL12 reduces its steady-state protein level, impairs integration into the large mitochondrial ribosomal subunit, and causes an overall mitochondrial translation defect with significant reduction of COXI, COXII, and COXIII synthesis. This indicates MRPL12 is required for proper mitochondrial ribosome assembly and translation, with Ala181 predicted to lie at an interface for elongation factor interaction. Patient fibroblast analysis, MRPL12 protein level quantification, ribosomal subunit fractionation/integration assay, [35S]-methionine mitochondrial translation assay Biochimica et biophysica acta High 23603806
2020 SQSTM1/p62 regulates mitochondrial DNA (mtDNA) expression via p38-dependent upregulation of MRPL12 in renal tubular epithelial cells. ATF2, a downstream effector of p38, directly binds to the MRPL12 promoter to drive its transcription. MRPL12 mediates SQSTM1/p62-induced mtDNA expression during serum deprivation and hypoxia. Promoter binding assay (direct binding site for ATF2 in MRPL12 promoter), p38 inhibition, SQSTM1/p62 knockdown/overexpression, mtDNA expression assays, TEC-specific knockout mice iScience Medium 32805647
2021 Nrf2 acts as a transcription factor for MRPL12: Nrf2 levels correlate with MRPL12 expression, and MRPL12 positively controls mitochondrial oxidative phosphorylation (OXPHOS) and mtDNA copy number. Overexpression of MRPL12 alleviates OXPHOS impairment induced by high glucose in proximal tubular epithelial cells. Mass spectrometry-based proteomics, immunohistochemistry, MRPL12 overexpression with OXPHOS functional assays, co-immunofluorescence of MRPL12 and Nrf2 Free radical biology & medicine Medium 33444714
2021 ING2 modulates mitochondrial respiration in renal tubular epithelial cells by regulating the ubiquitination of MRPL12, thereby controlling its cellular stability and abundance; this in turn affects mtDNA transcription and mitochondrial respiration. Western blot, PCR, immunofluorescence, co-immunoprecipitation, oxygen consumption rate assay, in vitro and in vivo ischemic kidney injury models Frontiers in cell and developmental biology Medium 34434929
2023 CUL3 (an E3 ubiquitin ligase) directly interacts with MRPL12 and induces K63-linked ubiquitination at K150, resulting in mitochondrial biosynthesis dysfunction. Under high-glucose conditions, CUL3 is upregulated and CUL3-mediated MRPL12 ubiquitination is increased; CUL3 knockdown stabilizes MRPL12 and protects mitochondrial biosynthesis. Co-immunoprecipitation, site-directed mutagenesis of K150, ubiquitination assay (K63-linked), CUL3 knockdown, mitochondrial biosynthesis functional assays The FEBS journal Medium 37526061
2023 MRPL12 specifically binds to adenosine nucleotide translocase 3 (ANT3) under normal physiological conditions, stabilizing the mitochondrial permeability transition pore (MPTP) and maintaining mitochondrial membrane homeostasis. During AKI, reduced MRPL12 expression leads to decreased MRPL12-ANT3 interaction, ANT3 conformational change, abnormal MPTP opening, and cell apoptosis. MRPL12 overexpression protects tubular epithelial cells from MPTP opening and apoptosis during hypoxia/reoxygenation. Co-immunoprecipitation (MRPL12-ANT3 interaction), MPTP opening assay, mitochondrial membrane potential measurement, MRPL12 overexpression in H/R model, cell apoptosis assays iScience Medium 37182101
2023 The m6A reader YTHDC2 binds to m6A-modified MRPL12 mRNA and destabilizes it, thereby reducing MRPL12 protein levels and suppressing lung adenocarcinoma tumorigenesis. Methylated RNA immunoprecipitation (MeRIP), YTHDC2 overexpression/knockdown, MRPL12 mRNA stability assay, in vivo tumor model Molecular biotechnology Medium 38129673
2024 UBASH3B binds to MRPL12 and dephosphorylates it at tyrosine 60 (Y60). Y60 phosphorylation promotes MRPL12 binding to POLRMT (mitochondrial RNA polymerase), upregulating mitochondrial metabolism/OXPHOS and driving LUAD progression. Dephosphorylation at Y60 by UBASH3B impedes MRPL12-POLRMT interaction and reduces mitochondrial metabolism. Mass spectrometry for phosphorylation site identification, Co-immunoprecipitation (MRPL12-UBASH3B and MRPL12-POLRMT), site-directed mutagenesis of Y60, in vivo mouse LUAD model, patient-derived organoids Journal of experimental & clinical cancer research Medium 39343960
2025 MRPL12 is acetylated at lysine 163 (K163) by acetyltransferase TIP60 and deacetylated by SIRT5. K163 acetylation enhances MRPL12 binding to POLRMT, promoting mitochondrial biosynthesis and metabolism while suppressing glycolysis. This acetylation is downregulated in ccRCC, and restoring K163 acetylation inhibits ccRCC progression in vitro and in vivo. Co-immunoprecipitation (TIP60-MRPL12, SIRT5-MRPL12, MRPL12-POLRMT), site-directed mutagenesis of K163, in vitro and in vivo ccRCC models, metabolic flux assays Cell death & disease Medium 40858596

Source papers

Stage 0 corpus · 15 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2013 Mutations in mitochondrial ribosomal protein MRPL12 leads to growth retardation, neurological deterioration and mitochondrial translation deficiency. Biochimica et biophysica acta 80 23603806
2005 The Drosophila mitochondrial ribosomal protein mRpL12 is required for Cyclin D/Cdk4-driven growth. The EMBO journal 64 15692573
1996 A delayed-early response nuclear gene encoding MRPL12, the mitochondrial homologue to the bacterial translational regulator L7/L12 protein. The Journal of biological chemistry 31 8626705
2021 Transcription of MRPL12 regulated by Nrf2 contributes to the mitochondrial dysfunction in diabetic kidney disease. Free radical biology & medicine 29 33444714
2020 SQSTM1/p62 Controls mtDNA Expression and Participates in Mitochondrial Energetic Adaption via MRPL12. iScience 22 32805647
2023 MRPL12-ANT3 interaction involves in acute kidney injury via regulating MPTP of tubular epithelial cells. iScience 17 37182101
1997 Expression and human chromosomal localization to 17q25 of the growth-regulated gene encoding the mitochondrial ribosomal protein MRPL12. Genomics 15 9169145
2024 UBASH3B-mediated MRPL12 Y60 dephosphorylation inhibits LUAD development by driving mitochondrial metabolism reprogramming. Journal of experimental & clinical cancer research : CR 12 39343960
2024 Role of mitochondrial ribosomal protein L7/L12 (MRPL12) in diabetic ischemic heart disease. Free radical biology & medicine 11 38977138
2023 CUL3 induces mitochondrial dysfunction via MRPL12 ubiquitination in renal tubular epithelial cells. The FEBS journal 11 37526061
2023 The m6A Reader YTHDC2 Suppresses Lung Adenocarcinoma Tumorigenesis by Destabilizing MRPL12. Molecular biotechnology 10 38129673
2021 ING2 Controls Mitochondrial Respiration via Modulating MRPL12 Ubiquitination in Renal Tubular Epithelial Cells. Frontiers in cell and developmental biology 6 34434929
2021 Co-immunofluorescence of MRPL12 and Nrf2 in HK2 Cells. Bio-protocol 5 34761064
2025 MRPL12 K163 acetylation inhibits ccRCC via driving mitochondrial metabolic reprogramming. Cell death & disease 1 40858596
2025 High MRPL12 expression drives esophageal cancer proliferation, invasion and migration. Bulletin du cancer 0 40967941

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