{"gene":"MRPL12","run_date":"2026-04-28T18:30:28","timeline":{"discoveries":[{"year":1996,"finding":"MRPL12 localizes predominantly to mitochondria (confirmed by immunofluorescence and cell fractionation), associates with ribosomal structures in vitro, and expression of a dominant-negative truncated form reduces cell growth by inhibiting mitochondrial ATP production.","method":"Immunofluorescence, cell fractionation, in vitro ribosome co-fractionation, dominant-negative overexpression with ATP production assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (localization, fractionation, functional loss-of-function) in a single foundational study","pmids":["8626705"],"is_preprint":false},{"year":2005,"finding":"In Drosophila, mRpL12 is required for CycD/Cdk4-driven cell growth; mRpL12 loss-of-function suppresses CycD/Cdk4-induced overgrowth, reduces mitochondrial activity, and places mRpL12 in a common pathway with CycD/Cdk4 and Hif-1 prolyl hydroxylase (Hph) that controls cell growth via mitochondrial activity.","method":"Genetic loss-of-function screen, epistasis analysis, mitochondrial activity assays in Drosophila eye","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 — genetic epistasis with multiple alleles and functional readouts, replicated in vivo","pmids":["15692573"],"is_preprint":false},{"year":2013,"finding":"The p.Ala181Val mutation in MRPL12 decreases steady-state MRPL12 protein levels, impairs integration of MRPL12 into the mitochondrial large ribosomal subunit, and causes an overall mitochondrial translation defect with significant reduction of COXI, COXII, and COXIII synthesis; modeling places Ala181 at a predicted interface with elongation factors.","method":"Patient mutation analysis, ribosome subunit fractionation, mitochondrial translation assay (radiolabeling), structural modeling","journal":"Biochimica et biophysica acta","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (ribosome fractionation, translation assay, structural modeling) with patient-derived cells","pmids":["23603806"],"is_preprint":false},{"year":2020,"finding":"SQSTM1/p62 upregulates MRPL12 via p38-ATF2 signaling; ATF2 directly binds the MRPL12 promoter, and p62-induced mtDNA expression and mitochondrial OXPHOS are mediated through MRPL12 in renal tubular epithelial cells.","method":"Promoter binding assay (ATF2 binding site identification), p38 inhibition, MRPL12 knockdown/overexpression, OXPHOS assay, TECs-specific p62 knockout mice","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 — promoter binding, epistasis via KO, but single laboratory","pmids":["32805647"],"is_preprint":false},{"year":2021,"finding":"Nrf2 acts as a transcription factor for MRPL12; Nrf2 and MRPL12 levels correlate in diabetic kidney disease and Nrf2 regulates MRPL12-dependent mitochondrial OXPHOS in proximal tubular epithelial cells.","method":"Co-immunofluorescence, overexpression/knockdown, OXPHOS assay, proteomics","journal":"Free radical biology & medicine","confidence":"Medium","confidence_rationale":"Tier 3 — co-localization and correlative data; direct Nrf2-MRPL12 promoter binding inferred but not definitively proven by ChIP in this paper","pmids":["33444714"],"is_preprint":false},{"year":2021,"finding":"ING2 regulates MRPL12 ubiquitination, modulating MRPL12 protein stability and abundance, thereby controlling mitochondrial respiration and mtDNA transcription in renal tubular epithelial cells.","method":"Co-immunoprecipitation, Western blot, PCR, oxygen consumption rate assay, overexpression/knockdown, in vivo IRI model","journal":"Frontiers in cell and developmental biology","confidence":"Medium","confidence_rationale":"Tier 2/3 — co-IP demonstrating ING2-MRPL12 interaction, functional rescue, single laboratory","pmids":["34434929"],"is_preprint":false},{"year":2023,"finding":"CUL3 E3 ubiquitin ligase directly interacts with MRPL12 and induces K63-linked ubiquitination at K150, leading to mitochondrial biosynthesis dysfunction; CUL3 knockdown stabilizes MRPL12 and protects mitochondrial biosynthesis under high-glucose conditions.","method":"Co-immunoprecipitation, ubiquitination assay, site-directed mutagenesis (K150), CUL3 knockdown, mitochondrial biosynthesis assay","journal":"The FEBS journal","confidence":"High","confidence_rationale":"Tier 1–2 — direct interaction by Co-IP, specific ubiquitination site identified by mutagenesis, functional consequence demonstrated","pmids":["37526061"],"is_preprint":false},{"year":2023,"finding":"MRPL12 specifically binds ANT3 (adenosine nucleotide translocase 3) under normal conditions to stabilize the mitochondrial permeability transition pore (MPTP); during AKI, decreased MRPL12 reduces MRPL12-ANT3 interaction, causing ANT3 conformational change, MPTP opening, and apoptosis; MRPL12 overexpression prevents MPTP opening.","method":"Co-immunoprecipitation, MRPL12 overexpression/knockdown, MPTP opening assay, hypoxia/reoxygenation model, apoptosis assay","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 — reciprocal Co-IP, functional rescue by overexpression, single laboratory","pmids":["37182101"],"is_preprint":false},{"year":2023,"finding":"YTHDC2 (m6A reader) binds m6A-modified MRPL12 mRNA and destabilizes MRPL12 expression in an m6A-dependent manner, suppressing lung adenocarcinoma tumorigenesis.","method":"Methylated RNA immunoprecipitation (MeRIP), YTHDC2 overexpression/knockdown, MRPL12 rescue experiments, in vivo mouse LUAD model","journal":"Molecular biotechnology","confidence":"Medium","confidence_rationale":"Tier 2 — MeRIP showing m6A on MRPL12 mRNA, functional epistasis, single laboratory","pmids":["38129673"],"is_preprint":false},{"year":2024,"finding":"MRPL12 is phosphorylated at tyrosine 60 (Y60); phospho-Y60 promotes binding of MRPL12 to POLRMT (mitochondrial RNA polymerase), upregulating mitochondrial OXPHOS and LUAD progression; UBASH3B dephosphorylates MRPL12 Y60, reducing POLRMT binding and inhibiting LUAD.","method":"Mass spectrometry (PTM identification), co-immunoprecipitation, Y60 mutagenesis, LUAD mouse models (Tp53fl/fl;KrasG12D), patient-derived organoids, in vitro and in vivo functional assays","journal":"Journal of experimental & clinical cancer research","confidence":"High","confidence_rationale":"Tier 1–2 — MS-identified PTM, mutagenesis of key site, co-IP demonstrating MRPL12-POLRMT interaction, multiple in vivo models","pmids":["39343960"],"is_preprint":false},{"year":2025,"finding":"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; K163 acetylation is downregulated in ccRCC and its restoration inhibits ccRCC progression.","method":"Co-immunoprecipitation (TIP60, SIRT5, POLRMT binding), acetylation site mutagenesis (K163), in vitro and in vivo ccRCC models, metabolic assays","journal":"Cell death & disease","confidence":"High","confidence_rationale":"Tier 1–2 — specific acetylation site identified, writer/eraser identified, mechanism via POLRMT binding demonstrated by Co-IP and mutagenesis","pmids":["40858596"],"is_preprint":false}],"current_model":"MRPL12 is a mitochondrial large ribosomal subunit protein that functions as a translational and transcriptional regulator of mitochondrial gene expression: it associates with the mitoribosome to support translation of respiratory chain subunits, directly binds the mitochondrial RNA polymerase POLRMT to promote mtDNA transcription, and its activity is regulated by post-translational modifications (phosphorylation at Y60 by upstream kinases/dephosphorylated by UBASH3B, K63-linked ubiquitination at K150 by CUL3, and acetylation at K163 by TIP60/SIRT5), with additional roles in stabilizing the mitochondrial permeability transition pore via interaction with ANT3."},"narrative":{"teleology":[{"year":1996,"claim":"Establishing that MRPL12 is a mitochondrial ribosomal protein whose disruption impairs mitochondrial ATP production resolved its subcellular assignment and linked it to energy metabolism.","evidence":"Immunofluorescence, cell fractionation, in vitro ribosome co-fractionation, and dominant-negative overexpression with ATP assay in mammalian cells","pmids":["8626705"],"confidence":"High","gaps":["Direct role in translation versus ribosome assembly not distinguished","No identification of specific mitoribosome contacts"]},{"year":2005,"claim":"Genetic epistasis in Drosophila revealed that mRpL12 operates downstream of CycD/Cdk4 and in concert with Hph to drive cell growth through mitochondrial activity, placing mitoribosomal function within a growth-control signaling axis.","evidence":"Loss-of-function screen and epistasis analysis with mitochondrial activity readouts in Drosophila eye","pmids":["15692573"],"confidence":"High","gaps":["Whether CycD/Cdk4 regulation of MRPL12 is direct or transcriptional was not resolved","Conservation of this pathway in mammals not tested"]},{"year":2013,"claim":"Patient-derived p.Ala181Val mutation demonstrated that MRPL12 integrity is required for mitoribosome incorporation and mitochondrial translation of respiratory chain subunits, establishing MRPL12 as a disease gene for combined OXPHOS deficiency.","evidence":"Patient mutation analysis, ribosome subunit fractionation, radiolabeled mitochondrial translation assay, and structural modeling","pmids":["23603806"],"confidence":"High","gaps":["Structural basis of Ala181-mediated elongation factor interaction not resolved at atomic level","No rescue experiment to confirm causality of the single mutation"]},{"year":2020,"claim":"Identification of ATF2 as a direct transcriptional activator of the MRPL12 promoter, downstream of p62/p38 signaling, established how upstream stress pathways regulate MRPL12 expression to control mitochondrial gene expression.","evidence":"Promoter binding assay, p38 inhibition, MRPL12 knockdown/overexpression, OXPHOS assay, and tissue-specific p62 knockout mice in renal tubular epithelial cells","pmids":["32805647"],"confidence":"Medium","gaps":["Single laboratory study","Whether ATF2 binding is sufficient or requires co-activators not tested","Generalizability beyond renal epithelium unclear"]},{"year":2021,"claim":"Discovery that ING2 regulates MRPL12 ubiquitination and protein stability connected protein turnover mechanisms to MRPL12-dependent mitochondrial respiration and mtDNA transcription.","evidence":"Co-immunoprecipitation, oxygen consumption assay, knockdown/overexpression, and in vivo ischemia-reperfusion injury model","pmids":["34434929"],"confidence":"Medium","gaps":["The E3 ligase identity was not determined in this study","Ubiquitination sites on MRPL12 not mapped","Single laboratory"]},{"year":2023,"claim":"CUL3 was identified as the E3 ubiquitin ligase that K63-ubiquitinates MRPL12 at K150, and MRPL12 was shown to bind ANT3 to stabilize the mitochondrial permeability transition pore, expanding MRPL12's roles beyond translation/transcription to pore regulation.","evidence":"Co-IP, ubiquitination assays with K150 mutagenesis, CUL3 knockdown (for ubiquitination); reciprocal Co-IP, MPTP opening assay, hypoxia/reoxygenation model (for ANT3 interaction)","pmids":["37526061","37182101"],"confidence":"High","gaps":["Adaptor protein linking CUL3 to MRPL12 not identified","Whether K63-ubiquitination affects MRPL12 localization or only stability is unclear","ANT3 interaction site on MRPL12 not mapped"]},{"year":2024,"claim":"Phosphorylation at Y60 was shown to be the switch controlling MRPL12-POLRMT interaction and thus mitochondrial transcription, with UBASH3B identified as the opposing phosphatase, directly linking a specific post-translational modification to the transcriptional function of MRPL12.","evidence":"Mass spectrometry PTM identification, Y60 mutagenesis, Co-IP for POLRMT binding, Kras-driven LUAD mouse models, and patient-derived organoids","pmids":["39343960"],"confidence":"High","gaps":["The kinase that phosphorylates Y60 was not identified","Whether Y60 phosphorylation also affects ribosomal integration is untested"]},{"year":2025,"claim":"Acetylation at K163 by TIP60 (erased by SIRT5) was identified as a second PTM that enhances MRPL12-POLRMT binding and mitochondrial biosynthesis, revealing that two distinct modifications on MRPL12 converge on the same transcriptional interaction.","evidence":"Co-IP for TIP60, SIRT5, and POLRMT; K163 mutagenesis; in vitro and in vivo ccRCC models; metabolic assays","pmids":["40858596"],"confidence":"High","gaps":["Interplay between Y60 phosphorylation and K163 acetylation not examined","Structural basis for how K163 acetylation enhances POLRMT binding unknown"]},{"year":null,"claim":"The kinase responsible for MRPL12 Y60 phosphorylation, the structural basis of the MRPL12-POLRMT interface, and whether MRPL12's ribosomal versus extra-ribosomal (POLRMT-binding, ANT3-binding) pools are independently regulated remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["Y60 kinase identity unknown","No high-resolution structure of MRPL12-POLRMT complex","Relative contributions of ribosomal vs. extra-ribosomal MRPL12 to OXPHOS not quantified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[9,10]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,2,7]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,2]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[9,10]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[1,3,10]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[2]}],"complexes":["mitochondrial large ribosomal subunit (39S)"],"partners":["POLRMT","ANT3","CUL3","UBASH3B","TIP60","SIRT5","ING2"],"other_free_text":[]},"mechanistic_narrative":"MRPL12 is a component of the mitochondrial large ribosomal subunit that serves as a central regulator of both mitochondrial translation and transcription, coupling ribosome function with mtDNA-encoded gene expression to control oxidative phosphorylation. MRPL12 integrates into the mitoribosome to support synthesis of respiratory chain subunits, and its loss or mutation (e.g., p.Ala181Val) impairs mitoribosome assembly and mitochondrial translation [PMID:8626705, PMID:23603806]. Independent of its ribosomal role, MRPL12 directly binds the mitochondrial RNA polymerase POLRMT to stimulate mtDNA transcription, an interaction regulated by phosphorylation at Y60 (opposed by the phosphatase UBASH3B), acetylation at K163 (written by TIP60, erased by SIRT5), and K63-linked ubiquitination at K150 (mediated by CUL3) [PMID:39343960, PMID:40858596, PMID:37526061]. Biallelic MRPL12 mutations cause combined oxidative phosphorylation deficiency through defective mitoribosome incorporation and reduced synthesis of respiratory chain complexes [PMID:23603806]."},"prefetch_data":{"uniprot":{"accession":"P52815","full_name":"Large ribosomal subunit protein bL12m","aliases":["39S ribosomal protein L12, mitochondrial","L12mt","MRP-L12","5c5-2"],"length_aa":198,"mass_kda":21.3,"function":"As a component of the mitochondrial large ribosomal subunit, plays a role in mitochondrial translation (PubMed:23603806). When present in mitochondria as a free protein not associated with the ribosome, associates with mitochondrial RNA polymerase POLRMT to activate transcription (PubMed:22003127). Required for POLRMT stability (PubMed:26586915)","subcellular_location":"Mitochondrion matrix","url":"https://www.uniprot.org/uniprotkb/P52815/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MRPL12","classification":"Not Classified","n_dependent_lines":627,"n_total_lines":1208,"dependency_fraction":0.5190397350993378},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"HDAC2","stoichiometry":4.0},{"gene":"CALM2","stoichiometry":0.2},{"gene":"CALM3","stoichiometry":0.2},{"gene":"LSM14A","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/MRPL12","total_profiled":1310},"omim":[{"mim_id":"618951","title":"COMBINED OXIDATIVE PHOSPHORYLATION DEFICIENCY 45; COXPD45","url":"https://www.omim.org/entry/618951"},{"mim_id":"617228","title":"COMBINED OXIDATIVE PHOSPHORYLATION DEFICIENCY 31; COXPD31","url":"https://www.omim.org/entry/617228"},{"mim_id":"614919","title":"NITRIC OXIDE-ASSOCIATED PROTEIN 1; NOA1","url":"https://www.omim.org/entry/614919"},{"mim_id":"610822","title":"SOLUTE CARRIER FAMILY 25, MEMBER 41; SLC25A41","url":"https://www.omim.org/entry/610822"},{"mim_id":"609060","title":"COMBINED OXIDATIVE PHOSPHORYLATION DEFICIENCY 1; COXPD1","url":"https://www.omim.org/entry/609060"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Mitochondria","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/MRPL12"},"hgnc":{"alias_symbol":["MRPL7/L12","MRPL7","bL12m"],"prev_symbol":["RPML12"]},"alphafold":{"accession":"P52815","domains":[{"cath_id":"3.30.1390.10","chopping":"130-198","consensus_level":"high","plddt":87.7938,"start":130,"end":198}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P52815","model_url":"https://alphafold.ebi.ac.uk/files/AF-P52815-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P52815-F1-predicted_aligned_error_v6.png","plddt_mean":66.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MRPL12","jax_strain_url":"https://www.jax.org/strain/search?query=MRPL12"},"sequence":{"accession":"P52815","fasta_url":"https://rest.uniprot.org/uniprotkb/P52815.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P52815/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P52815"}},"corpus_meta":[{"pmid":"23603806","id":"PMC_23603806","title":"Mutations in mitochondrial ribosomal protein MRPL12 leads to growth retardation, neurological deterioration and mitochondrial translation deficiency.","date":"2013","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/23603806","citation_count":80,"is_preprint":false},{"pmid":"15692573","id":"PMC_15692573","title":"The Drosophila mitochondrial ribosomal protein mRpL12 is required for Cyclin D/Cdk4-driven growth.","date":"2005","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/15692573","citation_count":64,"is_preprint":false},{"pmid":"8626705","id":"PMC_8626705","title":"A delayed-early response nuclear gene encoding MRPL12, the mitochondrial homologue to the bacterial translational regulator L7/L12 protein.","date":"1996","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/8626705","citation_count":31,"is_preprint":false},{"pmid":"33444714","id":"PMC_33444714","title":"Transcription of MRPL12 regulated by Nrf2 contributes to the mitochondrial dysfunction in diabetic kidney disease.","date":"2021","source":"Free radical biology & medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33444714","citation_count":29,"is_preprint":false},{"pmid":"32805647","id":"PMC_32805647","title":"SQSTM1/p62 Controls mtDNA Expression and Participates in Mitochondrial Energetic Adaption via MRPL12.","date":"2020","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/32805647","citation_count":20,"is_preprint":false},{"pmid":"37182101","id":"PMC_37182101","title":"MRPL12-ANT3 interaction involves in acute kidney injury via regulating MPTP of tubular epithelial cells.","date":"2023","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/37182101","citation_count":17,"is_preprint":false},{"pmid":"9169145","id":"PMC_9169145","title":"Expression and human chromosomal localization to 17q25 of the growth-regulated gene encoding the mitochondrial ribosomal protein MRPL12.","date":"1997","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/9169145","citation_count":15,"is_preprint":false},{"pmid":"39343960","id":"PMC_39343960","title":"UBASH3B-mediated MRPL12 Y60 dephosphorylation inhibits LUAD development by driving mitochondrial metabolism reprogramming.","date":"2024","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/39343960","citation_count":12,"is_preprint":false},{"pmid":"38977138","id":"PMC_38977138","title":"Role of mitochondrial ribosomal protein L7/L12 (MRPL12) in diabetic ischemic heart disease.","date":"2024","source":"Free radical biology & medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38977138","citation_count":11,"is_preprint":false},{"pmid":"38129673","id":"PMC_38129673","title":"The m6A Reader YTHDC2 Suppresses Lung Adenocarcinoma Tumorigenesis by Destabilizing MRPL12.","date":"2023","source":"Molecular biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/38129673","citation_count":10,"is_preprint":false},{"pmid":"37526061","id":"PMC_37526061","title":"CUL3 induces mitochondrial dysfunction via MRPL12 ubiquitination in renal tubular epithelial cells.","date":"2023","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/37526061","citation_count":9,"is_preprint":false},{"pmid":"34434929","id":"PMC_34434929","title":"ING2 Controls Mitochondrial Respiration via Modulating MRPL12 Ubiquitination in Renal Tubular Epithelial Cells.","date":"2021","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/34434929","citation_count":6,"is_preprint":false},{"pmid":"34761064","id":"PMC_34761064","title":"Co-immunofluorescence of MRPL12 and Nrf2 in HK2 Cells.","date":"2021","source":"Bio-protocol","url":"https://pubmed.ncbi.nlm.nih.gov/34761064","citation_count":5,"is_preprint":false},{"pmid":"40967941","id":"PMC_40967941","title":"High MRPL12 expression drives esophageal cancer proliferation, invasion and migration.","date":"2025","source":"Bulletin du cancer","url":"https://pubmed.ncbi.nlm.nih.gov/40967941","citation_count":0,"is_preprint":false},{"pmid":"40858596","id":"PMC_40858596","title":"MRPL12 K163 acetylation inhibits ccRCC via driving mitochondrial metabolic reprogramming.","date":"2025","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/40858596","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8464,"output_tokens":2741,"usd":0.033253},"stage2":{"model":"claude-opus-4-6","input_tokens":6072,"output_tokens":2396,"usd":0.13539},"total_usd":0.168643,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1996,\n      \"finding\": \"MRPL12 localizes predominantly to mitochondria (confirmed by immunofluorescence and cell fractionation), associates with ribosomal structures in vitro, and expression of a dominant-negative truncated form reduces cell growth by inhibiting mitochondrial ATP production.\",\n      \"method\": \"Immunofluorescence, cell fractionation, in vitro ribosome co-fractionation, dominant-negative overexpression with ATP production assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (localization, fractionation, functional loss-of-function) in a single foundational study\",\n      \"pmids\": [\"8626705\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"In Drosophila, mRpL12 is required for CycD/Cdk4-driven cell growth; mRpL12 loss-of-function suppresses CycD/Cdk4-induced overgrowth, reduces mitochondrial activity, and places mRpL12 in a common pathway with CycD/Cdk4 and Hif-1 prolyl hydroxylase (Hph) that controls cell growth via mitochondrial activity.\",\n      \"method\": \"Genetic loss-of-function screen, epistasis analysis, mitochondrial activity assays in Drosophila eye\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with multiple alleles and functional readouts, replicated in vivo\",\n      \"pmids\": [\"15692573\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"The p.Ala181Val mutation in MRPL12 decreases steady-state MRPL12 protein levels, impairs integration of MRPL12 into the mitochondrial large ribosomal subunit, and causes an overall mitochondrial translation defect with significant reduction of COXI, COXII, and COXIII synthesis; modeling places Ala181 at a predicted interface with elongation factors.\",\n      \"method\": \"Patient mutation analysis, ribosome subunit fractionation, mitochondrial translation assay (radiolabeling), structural modeling\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (ribosome fractionation, translation assay, structural modeling) with patient-derived cells\",\n      \"pmids\": [\"23603806\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SQSTM1/p62 upregulates MRPL12 via p38-ATF2 signaling; ATF2 directly binds the MRPL12 promoter, and p62-induced mtDNA expression and mitochondrial OXPHOS are mediated through MRPL12 in renal tubular epithelial cells.\",\n      \"method\": \"Promoter binding assay (ATF2 binding site identification), p38 inhibition, MRPL12 knockdown/overexpression, OXPHOS assay, TECs-specific p62 knockout mice\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — promoter binding, epistasis via KO, but single laboratory\",\n      \"pmids\": [\"32805647\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Nrf2 acts as a transcription factor for MRPL12; Nrf2 and MRPL12 levels correlate in diabetic kidney disease and Nrf2 regulates MRPL12-dependent mitochondrial OXPHOS in proximal tubular epithelial cells.\",\n      \"method\": \"Co-immunofluorescence, overexpression/knockdown, OXPHOS assay, proteomics\",\n      \"journal\": \"Free radical biology & medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — co-localization and correlative data; direct Nrf2-MRPL12 promoter binding inferred but not definitively proven by ChIP in this paper\",\n      \"pmids\": [\"33444714\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ING2 regulates MRPL12 ubiquitination, modulating MRPL12 protein stability and abundance, thereby controlling mitochondrial respiration and mtDNA transcription in renal tubular epithelial cells.\",\n      \"method\": \"Co-immunoprecipitation, Western blot, PCR, oxygen consumption rate assay, overexpression/knockdown, in vivo IRI model\",\n      \"journal\": \"Frontiers in cell and developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — co-IP demonstrating ING2-MRPL12 interaction, functional rescue, single laboratory\",\n      \"pmids\": [\"34434929\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CUL3 E3 ubiquitin ligase directly interacts with MRPL12 and induces K63-linked ubiquitination at K150, leading to mitochondrial biosynthesis dysfunction; CUL3 knockdown stabilizes MRPL12 and protects mitochondrial biosynthesis under high-glucose conditions.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, site-directed mutagenesis (K150), CUL3 knockdown, mitochondrial biosynthesis assay\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — direct interaction by Co-IP, specific ubiquitination site identified by mutagenesis, functional consequence demonstrated\",\n      \"pmids\": [\"37526061\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MRPL12 specifically binds ANT3 (adenosine nucleotide translocase 3) under normal conditions to stabilize the mitochondrial permeability transition pore (MPTP); during AKI, decreased MRPL12 reduces MRPL12-ANT3 interaction, causing ANT3 conformational change, MPTP opening, and apoptosis; MRPL12 overexpression prevents MPTP opening.\",\n      \"method\": \"Co-immunoprecipitation, MRPL12 overexpression/knockdown, MPTP opening assay, hypoxia/reoxygenation model, apoptosis assay\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP, functional rescue by overexpression, single laboratory\",\n      \"pmids\": [\"37182101\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"YTHDC2 (m6A reader) binds m6A-modified MRPL12 mRNA and destabilizes MRPL12 expression in an m6A-dependent manner, suppressing lung adenocarcinoma tumorigenesis.\",\n      \"method\": \"Methylated RNA immunoprecipitation (MeRIP), YTHDC2 overexpression/knockdown, MRPL12 rescue experiments, in vivo mouse LUAD model\",\n      \"journal\": \"Molecular biotechnology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — MeRIP showing m6A on MRPL12 mRNA, functional epistasis, single laboratory\",\n      \"pmids\": [\"38129673\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MRPL12 is phosphorylated at tyrosine 60 (Y60); phospho-Y60 promotes binding of MRPL12 to POLRMT (mitochondrial RNA polymerase), upregulating mitochondrial OXPHOS and LUAD progression; UBASH3B dephosphorylates MRPL12 Y60, reducing POLRMT binding and inhibiting LUAD.\",\n      \"method\": \"Mass spectrometry (PTM identification), co-immunoprecipitation, Y60 mutagenesis, LUAD mouse models (Tp53fl/fl;KrasG12D), patient-derived organoids, in vitro and in vivo functional assays\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — MS-identified PTM, mutagenesis of key site, co-IP demonstrating MRPL12-POLRMT interaction, multiple in vivo models\",\n      \"pmids\": [\"39343960\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"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; K163 acetylation is downregulated in ccRCC and its restoration inhibits ccRCC progression.\",\n      \"method\": \"Co-immunoprecipitation (TIP60, SIRT5, POLRMT binding), acetylation site mutagenesis (K163), in vitro and in vivo ccRCC models, metabolic assays\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — specific acetylation site identified, writer/eraser identified, mechanism via POLRMT binding demonstrated by Co-IP and mutagenesis\",\n      \"pmids\": [\"40858596\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MRPL12 is a mitochondrial large ribosomal subunit protein that functions as a translational and transcriptional regulator of mitochondrial gene expression: it associates with the mitoribosome to support translation of respiratory chain subunits, directly binds the mitochondrial RNA polymerase POLRMT to promote mtDNA transcription, and its activity is regulated by post-translational modifications (phosphorylation at Y60 by upstream kinases/dephosphorylated by UBASH3B, K63-linked ubiquitination at K150 by CUL3, and acetylation at K163 by TIP60/SIRT5), with additional roles in stabilizing the mitochondrial permeability transition pore via interaction with ANT3.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"MRPL12 is a component of the mitochondrial large ribosomal subunit that serves as a central regulator of both mitochondrial translation and transcription, coupling ribosome function with mtDNA-encoded gene expression to control oxidative phosphorylation. MRPL12 integrates into the mitoribosome to support synthesis of respiratory chain subunits, and its loss or mutation (e.g., p.Ala181Val) impairs mitoribosome assembly and mitochondrial translation [PMID:8626705, PMID:23603806]. Independent of its ribosomal role, MRPL12 directly binds the mitochondrial RNA polymerase POLRMT to stimulate mtDNA transcription, an interaction regulated by phosphorylation at Y60 (opposed by the phosphatase UBASH3B), acetylation at K163 (written by TIP60, erased by SIRT5), and K63-linked ubiquitination at K150 (mediated by CUL3) [PMID:39343960, PMID:40858596, PMID:37526061]. Biallelic MRPL12 mutations cause combined oxidative phosphorylation deficiency through defective mitoribosome incorporation and reduced synthesis of respiratory chain complexes [PMID:23603806].\",\n  \"teleology\": [\n    {\n      \"year\": 1996,\n      \"claim\": \"Establishing that MRPL12 is a mitochondrial ribosomal protein whose disruption impairs mitochondrial ATP production resolved its subcellular assignment and linked it to energy metabolism.\",\n      \"evidence\": \"Immunofluorescence, cell fractionation, in vitro ribosome co-fractionation, and dominant-negative overexpression with ATP assay in mammalian cells\",\n      \"pmids\": [\"8626705\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct role in translation versus ribosome assembly not distinguished\", \"No identification of specific mitoribosome contacts\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Genetic epistasis in Drosophila revealed that mRpL12 operates downstream of CycD/Cdk4 and in concert with Hph to drive cell growth through mitochondrial activity, placing mitoribosomal function within a growth-control signaling axis.\",\n      \"evidence\": \"Loss-of-function screen and epistasis analysis with mitochondrial activity readouts in Drosophila eye\",\n      \"pmids\": [\"15692573\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CycD/Cdk4 regulation of MRPL12 is direct or transcriptional was not resolved\", \"Conservation of this pathway in mammals not tested\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Patient-derived p.Ala181Val mutation demonstrated that MRPL12 integrity is required for mitoribosome incorporation and mitochondrial translation of respiratory chain subunits, establishing MRPL12 as a disease gene for combined OXPHOS deficiency.\",\n      \"evidence\": \"Patient mutation analysis, ribosome subunit fractionation, radiolabeled mitochondrial translation assay, and structural modeling\",\n      \"pmids\": [\"23603806\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of Ala181-mediated elongation factor interaction not resolved at atomic level\", \"No rescue experiment to confirm causality of the single mutation\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identification of ATF2 as a direct transcriptional activator of the MRPL12 promoter, downstream of p62/p38 signaling, established how upstream stress pathways regulate MRPL12 expression to control mitochondrial gene expression.\",\n      \"evidence\": \"Promoter binding assay, p38 inhibition, MRPL12 knockdown/overexpression, OXPHOS assay, and tissue-specific p62 knockout mice in renal tubular epithelial cells\",\n      \"pmids\": [\"32805647\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single laboratory study\", \"Whether ATF2 binding is sufficient or requires co-activators not tested\", \"Generalizability beyond renal epithelium unclear\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Discovery that ING2 regulates MRPL12 ubiquitination and protein stability connected protein turnover mechanisms to MRPL12-dependent mitochondrial respiration and mtDNA transcription.\",\n      \"evidence\": \"Co-immunoprecipitation, oxygen consumption assay, knockdown/overexpression, and in vivo ischemia-reperfusion injury model\",\n      \"pmids\": [\"34434929\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The E3 ligase identity was not determined in this study\", \"Ubiquitination sites on MRPL12 not mapped\", \"Single laboratory\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"CUL3 was identified as the E3 ubiquitin ligase that K63-ubiquitinates MRPL12 at K150, and MRPL12 was shown to bind ANT3 to stabilize the mitochondrial permeability transition pore, expanding MRPL12's roles beyond translation/transcription to pore regulation.\",\n      \"evidence\": \"Co-IP, ubiquitination assays with K150 mutagenesis, CUL3 knockdown (for ubiquitination); reciprocal Co-IP, MPTP opening assay, hypoxia/reoxygenation model (for ANT3 interaction)\",\n      \"pmids\": [\"37526061\", \"37182101\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Adaptor protein linking CUL3 to MRPL12 not identified\", \"Whether K63-ubiquitination affects MRPL12 localization or only stability is unclear\", \"ANT3 interaction site on MRPL12 not mapped\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Phosphorylation at Y60 was shown to be the switch controlling MRPL12-POLRMT interaction and thus mitochondrial transcription, with UBASH3B identified as the opposing phosphatase, directly linking a specific post-translational modification to the transcriptional function of MRPL12.\",\n      \"evidence\": \"Mass spectrometry PTM identification, Y60 mutagenesis, Co-IP for POLRMT binding, Kras-driven LUAD mouse models, and patient-derived organoids\",\n      \"pmids\": [\"39343960\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The kinase that phosphorylates Y60 was not identified\", \"Whether Y60 phosphorylation also affects ribosomal integration is untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Acetylation at K163 by TIP60 (erased by SIRT5) was identified as a second PTM that enhances MRPL12-POLRMT binding and mitochondrial biosynthesis, revealing that two distinct modifications on MRPL12 converge on the same transcriptional interaction.\",\n      \"evidence\": \"Co-IP for TIP60, SIRT5, and POLRMT; K163 mutagenesis; in vitro and in vivo ccRCC models; metabolic assays\",\n      \"pmids\": [\"40858596\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Interplay between Y60 phosphorylation and K163 acetylation not examined\", \"Structural basis for how K163 acetylation enhances POLRMT binding unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The kinase responsible for MRPL12 Y60 phosphorylation, the structural basis of the MRPL12-POLRMT interface, and whether MRPL12's ribosomal versus extra-ribosomal (POLRMT-binding, ANT3-binding) pools are independently regulated remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Y60 kinase identity unknown\", \"No high-resolution structure of MRPL12-POLRMT complex\", \"Relative contributions of ribosomal vs. extra-ribosomal MRPL12 to OXPHOS not quantified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [9, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 2, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [9, 10]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [1, 3, 10]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [\n      \"mitochondrial large ribosomal subunit (39S)\"\n    ],\n    \"partners\": [\n      \"POLRMT\",\n      \"ANT3\",\n      \"CUL3\",\n      \"UBASH3B\",\n      \"TIP60\",\n      \"SIRT5\",\n      \"ING2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}