Affinage

PTCD1

Pentatricopeptide repeat-containing protein 1, mitochondrial · UniProt O75127

Length
700 aa
Mass
78.9 kDa
Annotated
2026-06-10
12 papers in source corpus 8 papers cited in narrative 8 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/5 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PTCD1 is a mitochondrial matrix pentatricopeptide repeat (PPR) RNA-binding protein that governs mitochondrial gene expression by acting on both mitochondrial tRNAs and rRNA (PMID:19651879, PMID:29617655). It binds mitochondrial leucine tRNAs and their precursor RNAs and negatively regulates their abundance and 3′-end processing, such that PTCD1 depletion raises leucine tRNA levels while overexpression lowers them (PMID:19651879, PMID:21857155). In parallel, PTCD1 binds 16S rRNA and is essential for its stability, pseudouridylation, and correct assembly of the mitochondrial large ribosomal subunit; its loss collapses mt-LSU biogenesis, abolishes mitochondrial translation, impairs electron transport chain assembly and oxidative phosphorylation, and forces a shift toward glycolysis (PMID:29617655, PMID:30948477). In vivo, tissue-specific knockout causes severe cardiomyopathy and premature death and triggers retrograde mTOR pathway activation with upregulated cytoplasmic protein synthesis, while reduced PTCD1 in neurons lowers ATP and dampens synaptic activity (PMID:29617655, PMID:30948477). PTCD1 levels are set by multiple inputs: leucine starvation lowers PTCD1 protein post-transcriptionally despite raising its mRNA (PMID:24710704), ZBTB16 transcriptionally activates PTCD1 through promoter binding (PMID:41482827), and mitochondrially localized FOXM1 directly binds PTCD1 protein to increase its levels and restrain respiration (PMID:32348194).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 2009 High

    Established PTCD1 as a matrix RNA-binding protein and a negative regulator of mitochondrial leucine tRNA levels, linking it directly to mitochondrial translation capacity.

    Evidence Subcellular fractionation, RNA immunoprecipitation, reciprocal RNAi/overexpression with RNA, protein and Complex IV readouts in 143B cells

    PMID:19651879

    Open questions at the time
    • Did not define the structural basis of tRNA recognition
    • Mechanism by which tRNA binding alters abundance not resolved
  2. 2011 Medium

    Placed PTCD1 in the mitochondrial tRNA maturation machinery by showing it influences 3′-end processing, distinct from the 5′ processing factors MRPP1/MRPP3 and partially overlapping ELAC2.

    Evidence Deep sequencing of mitochondrial transcript 5′/3′ ends in cells with manipulated PTCD1 levels

    PMID:21857155

    Open questions at the time
    • Single-lab sequencing inference without biochemical reconstitution
    • Whether PTCD1 acts directly or via processing enzymes unclear
  3. 2014 Medium

    Connected PTCD1 to nutrient sensing by showing leucine deprivation lowers PTCD1 protein post-transcriptionally, modulating leucine tRNA stability with amino acid availability.

    Evidence RT-qPCR, Western blot and RNAi in HepG2 cells under leucine starvation

    PMID:24710704

    Open questions at the time
    • Post-transcriptional mechanism lowering PTCD1 protein not identified
    • Physiological consequence of starvation response untested in vivo
  4. 2018 High

    Demonstrated a second, rRNA-centered function essential for mt-LSU biogenesis and showed loss of PTCD1 abolishes mitochondrial translation in vivo and triggers retrograde mTOR signalling.

    Evidence Tissue-specific CRISPR/Cas9 knockout mouse with rRNA binding, pseudouridylation mapping, ribosome assembly, translation and mTOR analyses

    PMID:29617655

    Open questions at the time
    • How a single protein both destabilizes tRNAs and stabilizes rRNA not mechanistically reconciled
    • Direct role in pseudouridylation versus permissive scaffolding unresolved
  5. 2019 High

    Generalized the rRNA/ribosome assembly role to bioenergetics and neuronal function, and linked an AD-associated variant to failure of energy production under stress.

    Evidence Knockdown/knockout cells with rRNA quantification, ribosome assembly, respiration, metabolic flux and primary neuron electrophysiology

    PMID:30948477

    Open questions at the time
    • Mechanism by which the AD variant impairs function not defined
    • Causal role of PTCD1 variant in disease not established by genetics
  6. 2020 Medium

    Identified mitochondrial FOXM1 as a direct protein partner that elevates PTCD1 and thereby suppresses ETC complexes and respiration, defining an upstream control of PTCD1 abundance.

    Evidence Site-directed mutagenesis restricting FOXM1 to mitochondria, co-immunoprecipitation with PTCD1, respiration/ETC assays

    PMID:32348194

    Open questions at the time
    • Single Co-IP without reciprocal structural validation
    • How FOXM1 binding stabilizes PTCD1 not determined
  7. 2020 Medium

    Showed that reduced PTCD1 dosage reprograms whole-body metabolism, with Akt-driven compensatory mitochondrial biogenesis conferring tissue-specific protection and harm under dietary stress.

    Evidence Haploinsufficient Ptcd1 mice on high-fat diet with tolerance tests, histology, biogenesis and Akt pathway analyses

    PMID:33024056

    Open questions at the time
    • Mechanism linking reduced mitochondrial translation to Akt activation unclear
    • Tissue-specificity of compensation not explained
  8. 2026 Medium

    Positioned PTCD1 downstream of ZBTB16 transcriptional control in a pathway maintaining Schwann cell mitochondrial integrity.

    Evidence Dual-luciferase promoter binding assay and PTCD1 siRNA epistasis in high-glucose-treated Schwann cells

    PMID:41482827

    Open questions at the time
    • Single-lab promoter and knockdown study
    • Whether ZBTB16-PTCD1 axis operates beyond Schwann cells untested

Open questions

Synthesis pass · forward-looking unresolved questions
  • How one PPR protein executes opposing fates on its RNA targets — destabilizing leucine tRNAs while stabilizing and promoting pseudouridylation of 16S rRNA — remains mechanistically unresolved.
  • No structural model of PTCD1 bound to tRNA versus rRNA
  • Direct enzymatic versus scaffolding contribution to pseudouridylation undefined
  • Coordination of PTCD1's transcriptional and post-translational regulation not integrated

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003723 RNA binding 4
Localization
GO:0005739 mitochondrion 2
Pathway
R-HSA-8953854 Metabolism of RNA 3 R-HSA-1430728 Metabolism 2
Partners
FOXM1
Complex memberships
mitochondrial large ribosomal subunit (mt-LSU)

Evidence

Reading pass · 8 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2009 PTCD1 is a mitochondrial matrix protein that associates with leucine tRNAs and precursor RNAs containing leucine tRNAs; knockdown increases leucine tRNA and precursor RNA abundance while overexpression reduces them, identifying PTCD1 as a negative regulator of mitochondrial leucine tRNA levels and hence mitochondrial translation. Subcellular fractionation (mitochondrial matrix localization), RNA immunoprecipitation, RNAi knockdown and overexpression in 143B cells with RT-qPCR and Western blot readouts, Complex IV activity assay Nucleic acids research High 19651879
2011 PTCD1 affects the 3′ end processing of mitochondrial tRNAs (distinct from MRPP1/MRPP3 which process 5′ ends and ELAC2 which also affects 3′ ends), as determined by deep sequencing of mitochondrial transcript ends in cells with altered PTCD1 levels. Deep sequencing (RNA-seq) of 5′ and 3′ ends of mitochondrial transcripts in cells with manipulated PTCD1 levels Cell cycle (Georgetown, Tex.) Medium 21857155
2014 PTCD1 protein levels are regulated post-transcriptionally during leucine starvation: leucine deprivation increases PTCD1 mRNA but decreases PTCD1 protein, and RNAi-mediated knockdown of PTCD1 stabilises mitochondrial leucine tRNAs (tRNA-Leu(CUN) and tRNA-Leu(UUR)), suggesting PTCD1 protein concentration modulates leucine tRNA stability in response to amino acid availability. RT-qPCR, Western blot, RNAi knockdown in HepG2 cells under leucine starvation conditions Amino acids Medium 24710704
2018 PTCD1 binds 16S rRNA and is essential for its stability, pseudouridylation, and correct biogenesis of the mitochondrial large ribosomal subunit (mt-LSU); CRISPR/Cas9 knockout in heart and skeletal muscle causes loss of mt-LSU assembly, abolishes mitochondrial translation, and leads to severe cardiomyopathy and premature death. Loss of PTCD1 also triggers retrograde signalling via transcriptional activation of the mTOR pathway and upregulation of cytoplasmic protein synthesis. CRISPR/Cas9 tissue-specific knockout mouse, transcriptome-wide RNA analysis, ribosome profiling/assembly assays, pseudouridylation mapping, mitochondrial translation assays, mTOR pathway analysis Cell reports High 29617655
2019 PTCD1 is required for normal mitochondrial 16S rRNA levels and proper assembly of the mitochondrial ribosome, mitochondrial translation, and electron transport chain assembly; loss of PTCD1 impairs oxidative phosphorylation, forcing cells to rely on glycolysis. In neurons, reduced PTCD1 expression lowers ATP levels and reduces spontaneous synaptic activity. An AD-associated PTCD1 variant fails to sustain energy production under metabolic stress. Knockdown/knockout cell lines, mitochondrial rRNA quantification, ribosome assembly assays, mitochondrial translation assay, oxygen consumption measurement, metabolic flux analysis, primary neuron electrophysiology The Journal of neuroscience High 30948477
2020 Mitochondrial FOXM1 directly binds PTCD1 protein and increases its levels, thereby inhibiting leucine-rich electron transport chain complexes and reducing mitochondrial respiration; this was shown using site-directed mutagenesis to restrict FOXM1 to mitochondria and co-immunoprecipitation/binding assays. Site-directed mutagenesis of FOXM1 (mitochondria-targeting vs. nuclear), co-immunoprecipitation of FOXM1 with PTCD1, mitochondrial respiration and ETC activity assays Molecular biology of the cell Medium 32348194
2020 Haploinsufficient Ptcd1 mice (reduced mitochondrial protein synthesis) fed a high-fat diet are protected from excessive weight gain through Akt-stimulated upregulation of mitochondrial biogenesis, resulting in improved glucose and insulin tolerance and reduced hepatic lipid accumulation, but inflammation of white adipose tissue and early skeletal muscle fibrosis are exacerbated; demonstrating tissue-specific recovery of OXPHOS via Akt/mitochondrial stress response. Haploinsufficient Ptcd1 mouse model, high-fat diet feeding, glucose and insulin tolerance tests, histology, mitochondrial biogenesis assays, Akt pathway analysis Aging Medium 33024056
2026 ZBTB16 transcriptionally activates PTCD1 by binding its promoter (confirmed by dual-luciferase assay); knockdown of PTCD1 abolishes ZBTB16's protective effects on Schwann cell differentiation and mitochondrial function, placing PTCD1 downstream of ZBTB16 in a pathway maintaining mitochondrial integrity in Schwann cells. Dual-luciferase reporter assay (ZBTB16 binding to PTCD1 promoter), PTCD1 siRNA knockdown in high-glucose-treated Schwann cells, mitochondrial function assays FASEB journal Medium 41482827

Source papers

Stage 0 corpus · 12 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2014 Use of whole-exome sequencing to determine the genetic basis of multiple mitochondrial respiratory chain complex deficiencies. JAMA 292 25058219
2011 RNA processing in human mitochondria. Cell cycle (Georgetown, Tex.) 201 21857155
2009 Pentatricopeptide repeat domain protein 1 lowers the levels of mitochondrial leucine tRNAs in cells. Nucleic acids research 75 19651879
2018 PTCD1 Is Required for 16S rRNA Maturation Complex Stability and Mitochondrial Ribosome Assembly. Cell reports 56 29617655
2020 FOXM1 nuclear transcription factor translocates into mitochondria and inhibits oxidative phosphorylation. Molecular biology of the cell 36 32348194
2017 Accurate Breakpoint Mapping in Apparently Balanced Translocation Families with Discordant Phenotypes Using Whole Genome Mate-Pair Sequencing. PloS one 27 28072833
2019 PTCD1 Is Required for Mitochondrial Oxidative-Phosphorylation: Possible Genetic Association with Alzheimer's Disease. The Journal of neuroscience : the official journal of the Society for Neuroscience 26 30948477
2019 Mitochondria and Alzheimer's: Is PTCD1 the Smoking Gun? Trends in neurosciences 9 31421943
2014 Mitochondrial leucine tRNA level and PTCD1 are regulated in response to leucine starvation. Amino acids 8 24710704
2020 Reduced mitochondrial translation prevents diet-induced metabolic dysfunction but not inflammation. Aging 6 33024056
2025 Analysis of mRNA Pentatricopeptide Repeat Domain 1 as a prospective oncogene in clear cell renal cell carcinoma that accelerates tumor cells proliferation and invasion via the Akt/GSK3β/β-catenin pathway. Discover oncology 4 39779600
2026 ZBTB16 Improves Myelin Damage in Diabetic Peripheral Neuropathy by Inhibiting Schwann Cell Dedifferentiation. FASEB journal : official publication of the Federation of American Societies for Experimental Biology 0 41482827

Missed literature

Know a paper Affinage missed for PTCD1? Flag it for the maintainers and the community.

No submissions yet.