Affinage

PCCA

Propionyl-CoA carboxylase alpha chain, mitochondrial · UniProt P05165

Length
728 aa
Mass
80.1 kDa
Annotated
2026-06-10
40 papers in source corpus 15 papers cited in narrative 15 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 8/8 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PCCA encodes the alpha subunit of mitochondrial propionyl-CoA carboxylase (PCC), a biotin-dependent enzyme that carboxylates propionyl-CoA in the catabolism of branched-chain amino acids, odd-chain fatty acids, cholesterol, and related metabolites (PMID:3460076, PMID:10502773). The alpha subunit carries the covalently bound biotin prosthetic group, identified by the conserved Ala-Met-Lys-Met biotin-binding motif in PCCA cDNA (PMID:3460076). PCCA assembles with the beta subunit (PCCB) into a heteromeric holoenzyme, and the alpha subunit is required to stabilize this complex: in PCCA-deficient patients PCCB is rapidly degraded and both subunits are absent, while re-expression of PCCA alone restores propionate flux in deficient fibroblasts (PMID:3687944, PMID:8434582, PMID:10502773). Most disease-causing missense and in-frame deletion mutations destabilize the protein and accelerate its turnover, indicating structural alterations incompatible with assembly into a stable, active oligomer (PMID:12385775, PMID:19157943). Loss of PCCA propagates beyond toxic propionyl-CoA accumulation to broad mitochondrial dysfunction, impairing oxidative phosphorylation, membrane potential, and distal TCA cycle flux (PMID:29159707). PCCA expression is shaped post-transcriptionally by a constitutive 84-bp cryptic pseudoexon whose inclusion introduces in-frame stop codons; a deep-intronic variant driving constitutive pseudoexon inclusion abolishes PCC activity and is correctable by antisense oligonucleotides that restore productive splicing (PMID:9887338, PMID:42028575). PCC-dependent catabolism is further modulated through partner binding: PPDPF and the lncRNA lncBADR each interfere with PCCA-mediated substrate degradation to elevate methionine/SAM or BCAA levels respectively (PMID:39694223, PMID:41013574), and PCCA additionally interacts with the Listeria monocytogenes phospholipase PlcB to restrict bacterial proliferation (PMID:38727222). Mutations and large genomic deletions in PCCA cause propionic acidemia (PMID:19157943, PMID:42028575).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 1986 High

    Established that PCCA is the gene for the alpha subunit of propionyl-CoA carboxylase and the carrier of the biotin prosthetic group, fixing its molecular identity.

    Evidence cDNA cloning with sequence identification of the conserved biotin-binding motif and somatic cell hybrid chromosomal mapping

    PMID:3460076

    Open questions at the time
    • No structural model of the holoenzyme
    • Catalytic mechanism inferred from family motif rather than directly assayed
  2. 1987 High

    Showed the alpha subunit is required to stabilize the beta subunit, establishing subunit interdependence as central to PCC assembly.

    Evidence Northern blot and pulse-labeling/immunoprecipitation across PCCA-deficient patient fibroblast strains

    PMID:3687944

    Open questions at the time
    • Stoichiometry of alpha/beta assembly not defined
    • Mechanism of PCCB degradation not identified
  3. 1993 High

    Demonstrated PCCA alone is sufficient to rescue the propionate-flux defect, and that its expression level does not normally limit holoenzyme activity.

    Evidence cDNA gene transfer into deficient fibroblasts with propionate flux and holoenzyme activity assays

    PMID:8434582

    Open questions at the time
    • Did not address rate-limiting steps under physiological conditions
    • Partial rescue limited by transfection efficiency
  4. 1999 High

    Resolved that loss of PCCA destabilizes the entire assembled complex and identified a constitutive cryptic pseudoexon that modulates productive mRNA, linking genotype to protein loss and to a splicing-based regulatory feature.

    Evidence Western blot, RT-PCR and complementation across patient cohorts plus RT-PCR/sequencing characterization of the 84-bp pseudoexon

    PMID:10502773 PMID:9887338

    Open questions at the time
    • Trans-factors regulating pseudoexon inclusion not identified
    • Physiological role of low-level pseudoexon inclusion unclear
  5. 2002 High

    Defined the dominant mechanism by which missense/in-frame mutations cause disease: protein destabilization and accelerated turnover preventing stable oligomer assembly.

    Evidence Expression of 11 mutations in deficient fibroblasts and cell-free systems with activity and stability assays

    PMID:12385775

    Open questions at the time
    • Degradation pathway/protease not identified
    • No structural rationale for individual destabilizing mutations
  6. 2009 Medium

    Identified large genomic deletions as a frequent pathogenic mechanism and confirmed an exon 3-4 in-frame deletion abolishes activity.

    Evidence MLPA, long-PCR, and eukaryotic expression with PCC activity assay

    PMID:19157943

    Open questions at the time
    • Repeat-mediated deletion mechanism inferred from sequence context, not directly demonstrated
  7. 2017 High

    Showed that PCCA deficiency causes broad mitochondrial energetic failure beyond precursor toxicity, reframing propionic acidemia as a mitochondrial disorder.

    Evidence C. elegans pcca-1 deletion with polarography, in vivo mitochondrial physiology, and 13C metabolic flux analysis

    PMID:29159707

    Open questions at the time
    • Mechanistic link between propionyl-CoA accumulation and OXPHOS impairment not fully resolved
    • Mammalian confirmation of all phenotypes pending
  8. 2021 Medium

    Established aberrant pre-mRNA splicing as a distinct pathogenic mechanism, including for synonymous and missense variants.

    Evidence Minigene splicing assays with RT-PCR/sequencing for 24 variants

    PMID:33923806

    Open questions at the time
    • Minigene context may not fully reflect endogenous splicing
    • Protein-level consequences predicted rather than measured
  9. 2024 Medium

    Revealed PCCA as a node controlled by protein and RNA partners and engaged in host-pathogen defense, expanding its biology beyond canonical metabolism.

    Evidence Mass spectrometry/Co-IP identifying PPDPF blocking PCCA-PCCB interaction; Co-IP/colocalization with Listeria PlcB plus knockdown/overexpression proliferation assays; metabolite profiling

    PMID:38727222 PMID:39694223

    Open questions at the time
    • Structural basis of partner interactions not defined
    • Single-lab findings without reciprocal/independent validation
    • Whether PlcB interaction depends on PCC catalytic function unknown
  10. 2024 Medium

    Demonstrated that dietary and metabolic state modulate the disease phenotype independent of residual enzyme activity, via substrate supply.

    Evidence Pcca-/-(A138T) propionic acidemia mouse model with metabolite profiling and PCC activity measurement during fasting

    PMID:38811689

    Open questions at the time
    • Microbiome contribution inferred, not directly manipulated
    • Translation to patient dietary management not established
  11. 2025 Medium

    Showed lncBADR directly binds PCCA to suppress BCAA catabolism in T cells, coupling PCCA metabolic activity to mTOR-Stat1 immune signaling.

    Evidence T cell-specific lncBADR knockout mice, RNA binding assays, metabolite profiling, and high-BCAA rescue feeding

    PMID:41013574

    Open questions at the time
    • Detailed lncBADR-PCCA binding interface not characterized
    • Single-lab finding
  12. 2026 High

    Provided a therapeutic proof-of-concept by correcting pseudoexon-driven loss of function, validating the cryptic exon as a splice-modulation target.

    Evidence Patient fibroblast analysis of a deep-intronic variant and antisense oligonucleotide rescue with enzymatic activity and protein expression readouts across cell lines

    PMID:42028575

    Open questions at the time
    • In vivo/clinical efficacy not established
    • Applicability limited to lines with residual activity >1%

Open questions

Synthesis pass · forward-looking unresolved questions
  • The structural basis of alpha/beta holoenzyme assembly and how diverse partner interactions (PPDPF, lncBADR, PlcB) mechanistically reroute substrate flux remain unresolved.
  • No high-resolution structure of human PCC in the timeline
  • Partner-binding interfaces and competitive mechanisms only partially mapped
  • Causal link between propionyl-CoA accumulation and broad mitochondrial dysfunction not fully defined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016874 ligase activity 3 GO:0016829 lyase activity 1 GO:0140657 ATP-dependent activity 1
Localization
GO:0005739 mitochondrion 2
Pathway
R-HSA-1430728 Metabolism 3
Complex memberships
propionyl-CoA carboxylase (PCC) holoenzyme

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1986 PCCA encodes the alpha subunit of propionyl-CoA carboxylase (PCC), a biotin-dependent enzyme. The alpha subunit contains the covalently bound biotin prosthetic group and the biotin-binding domain, as confirmed by the presence of the Ala-Met-Lys-Met sequence (biotin binding site conserved across biotin-dependent carboxylases) in PCCA cDNA clones. The PCCA gene was chromosomally mapped to chromosome 13 using somatic mouse-human hybrid panels. cDNA cloning, oligonucleotide probing, somatic cell hybrid panel mapping, Northern blot Proceedings of the National Academy of Sciences of the United States of America High 3460076
1987 In pccA complementation group patients (PCCA-deficient), alpha-chain mRNA is absent in most fibroblast strains, while beta-chain mRNA is present. The beta subunit (PCCB) is rapidly degraded in the absence of the alpha subunit, indicating that alpha-beta subunit interaction is required for stabilization of the beta chain. This confirms that PCCA encodes the alpha subunit of PCC. Northern blot with PCCA and PCCB cDNA probes, isotope-tracer labeling and immunoprecipitation of fibroblast extracts American journal of human genetics High 3687944
1993 Full-length PCCA cDNA, when expressed by DNA-mediated gene transfer in pccA-deficient fibroblasts, reconstitutes propionate flux to normal levels, confirming that PCCA alone is sufficient to rescue the enzymatic defect. Maximum PCC holoenzyme activity upon PCCA expression reached only 10-20% of normal controls (corresponding to transfected cell fraction), indicating PCCA expression level does not normally limit PCC holoenzyme activity or propionate flux. cDNA expression (gene transfer), propionate flux assay, PCC holoenzyme activity measurement in fibroblasts American journal of human genetics High 8434582
1999 PCCA is a mitochondrial heteropolymeric enzyme composed of alpha and beta subunits (encoded by PCCA and PCCB genes, respectively), involved in catabolism of branched-chain amino acids, odd-chain fatty acids, cholesterol, and other metabolites. In PCCA patients, combined absence of both alpha and beta subunits is observed by Western blot, indicating that the alpha subunit is required for stability of the assembled complex. Western blot, complementation assay, Northern blot, RT-PCR of patient fibroblasts Human mutation High 10502773
1999 The PCCA pre-mRNA contains a constitutive 84-bp cryptic (pseudo)exon derived from an intron between nucleotides 1209 and 1210. This cryptic exon is normally present at very low levels in all cells but becomes relatively detectable when the normal-length mRNA is destabilized by nonsense or frameshift mutations (R288X, 700del5, 1115del4, 1671IVS+5G->C). Incorporation of the 84-bp insertion causes translation termination via two in-frame stop codons. RT-PCR, sequencing, comparative analysis of patient and normal fibroblast cell lines Human molecular genetics High 9887338
2001 The PCCA gene spans more than 360 kb, consists of 24 exons (37–335 bp each), and the translation initiation codon is located 75 nucleotides upstream of the previously accepted site. The 5'-flanking region contains a putative CpG island (extending into exon 1 and part of intron 1), lacks a TATA box, but contains AP-1 sites and a consensus Sp1 (GC box) binding sequence in the proximal promoter. EST analysis, RT-PCR, genomic sequencing, promoter sequence analysis Molecular genetics and metabolism Medium 11592820
2002 Eleven PCCA missense mutations and one in-frame deletion, when expressed in patient fibroblasts and in a cell-free in vitro system, result in reduced PCC enzyme activity and increased protein turnover/instability. Most mutant proteins show an increased rate of degradation, indicating structural alterations incompatible with normal assembly into a stable, functional PCC oligomer. Expression in deficient fibroblasts, cell-free in vitro expression, PCC activity assay, protein stability assessment Biochimica et biophysica acta High 12385775
2009 Large genomic deletions in the PCCA gene (including frequent deletions of exons 3-4 and exon 23) cause propionic acidemia. A deletion of exons 3 and 4 results in an in-frame deletion of 39 amino acids; this in-frame deletion was expressed in a eukaryotic system and confirmed as pathogenic (loss of PCC activity). The high frequency of large deletions may be due to the abundance of intronic repetitive elements in the PCCA gene. MLPA, long-PCR, eukaryotic expression system, PCC activity assay Molecular genetics and metabolism Medium 19157943
2017 In C. elegans, deletion of pcca-1 (ortholog of human PCCA) globally impairs mitochondrial energy metabolism: reduces mitochondrial oxidative phosphorylation capacity and efficiency, increases mitochondrial matrix oxidant burden, decreases mitochondrial membrane potential and content, and inhibits distal TCA cycle flux. These findings indicate that PCC/PCCA deficiency causes broader metabolic dysfunction beyond toxic propionyl-CoA precursor accumulation. C. elegans gene deletion, direct polarography of isolated mitochondria, in vivo mitochondrial physiology quantitation, UPLC amino acid profiling, GC/MS with 13C-glucose metabolic flux analysis Journal of inherited metabolic disease High 29159707
2021 Twenty-four variants in PCCA (and PCCB) genes predicted to affect splicing were tested by minigene splicing assay; 13 variants (including one missense and two synonymous variants) caused significant alteration of splicing with predicted loss-of-function at the protein level, confirming their pathogenic mechanism via aberrant PCCA pre-mRNA splicing. Minigene splicing assay, RT-PCR, sequencing International journal of molecular sciences Medium 33923806
2024 PCCA (mitochondrial carboxylase) physically interacts with and colocalizes with Listeria monocytogenes phospholipase PlcB within host cells. The amino acids 504–508 of PCCA are critical for this interaction. Overexpression of PCCA (via pCMV-N-HA-PCCA plasmid) reduces L. monocytogenes proliferation, while siRNA knockdown of PCCA increases bacterial proliferation, demonstrating an inverse correlation between PCCA levels and bacterial survival. L. monocytogenes infection does not significantly alter PCCA expression levels. Co-immunoprecipitation/colocalization, siRNA knockdown, plasmid overexpression, bacterial proliferation assay, mRNA/protein expression analysis in HeLa cells Applied and environmental microbiology Medium 38727222
2024 PPDPF (pancreatic progenitor cell differentiation and proliferation factor) interacts with PCCA (identified by mass spectrometry) and blocks the interaction between PCCA and its partner subunit PCCB, thereby inhibiting PCC-dependent methionine catabolism via the C-Vomit pathway. This leads to elevated intracellular methionine and S-adenosylmethionine (SAM) levels and promotes esophageal squamous cell carcinoma progression. Mass spectrometry interaction screen, co-immunoprecipitation, metabolite measurement (methionine, SAM), PPDPF knockdown in vivo and in vitro Cancer letters Medium 39694223
2025 lncBADR binds directly to PCCA (and Mccc1) in T cells, inhibiting BCAA degradation. Knockout of lncBADR in T cells restores PCCA-mediated BCAA catabolism, decreasing intracellular BCAA levels and reducing mTOR-Stat1 signaling and IFN-γ secretion. High-BCAA feeding partially reversed the protective effects of lncBADR knockout, confirming that lncBADR acts through PCCA-dependent BCAA metabolism. T cell-specific lncBADR knockout mice, RNA binding assays, metabolite profiling, mTOR-Stat1 pathway analysis, IFN-γ measurement, rescue experiment (high-BCAA feeding) Journal of neuroinflammation Medium 41013574
2024 In Pcca-/-(A138T) mice (a propionic acidemia model), fasting reduces propionylcarnitine, the C3/C2 ratio, ammonia, and methylcitrate. This is attributed to significant reduction in microbiome-produced propionate and increased fatty acid oxidation (decreasing propionyl-CoA synthesis and enhancing acetyl-CoA synthesis) during fasting. Fasting-induced gluconeogenesis further facilitates propionyl-CoA catabolism without changing propionyl-CoA carboxylase activity. Pcca mutant mouse model, metabolite profiling (propionylcarnitine, C3/C2, ammonia, methylcitrate), measurement of PCC enzymatic activity, assessment of microbiome-derived propionate Communications biology Medium 38811689
2026 A deep-intronic PCCA variant (c.1285-1358C>G) causes constitutive inclusion of the known 84-bp pseudoexon in PCCA mRNA, abolishing functional PCCA and PCCB protein expression and severely reducing PCC activity. Antisense oligonucleotides (ASOs) targeting this pseudoexon restore productive PCCA splicing, rescue PCCA protein expression, and markedly increase PCC activity above wild-type levels in patient fibroblasts. ASO treatment was also effective in other PA fibroblast lines with residual activity >1% of normal. Patient fibroblast analysis, RT-PCR/sequencing, ASO transfection, PCC enzymatic activity assay, protein expression analysis Molecular therapy. Nucleic acids High 42028575

Source papers

Stage 0 corpus · 40 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1986 Isolation of cDNA clones coding for the alpha and beta chains of human propionyl-CoA carboxylase: chromosomal assignments and DNA polymorphisms associated with PCCA and PCCB genes. Proceedings of the National Academy of Sciences of the United States of America 110 3460076
1999 Overview of mutations in the PCCA and PCCB genes causing propionic acidemia. Human mutation 70 10502773
2001 Structure of the PCCA gene and distribution of mutations causing propionic acidemia. Molecular genetics and metabolism 34 11592820
2002 Functional characterization of PCCA mutations causing propionic acidemia. Biochimica et biophysica acta 33 12385775
2004 Mutation spectrum of the PCCA and PCCB genes in Japanese patients with propionic acidemia. Molecular genetics and metabolism 31 15059621
1997 Three novel splice mutations in the PCCA gene causing identical exon skipping in propionic acidemia patients. Human genetics 27 9385377
1993 Cloning of functional alpha propionyl CoA carboxylase and correction of enzyme deficiency in pccA fibroblasts. American journal of human genetics 27 8434582
1999 Detection of a normally rare transcript in propionic acidemia patients with mRNA destabilizing mutations in the PCCA gene. Human molecular genetics 24 9887338
2009 High frequency of large genomic deletions in the PCCA gene causing propionic acidemia. Molecular genetics and metabolism 23 19157943
2016 Effect of Substitution on the Aniline Moiety of the GPR88 Agonist 2-PCCA: Synthesis, Structure-Activity Relationships, and Molecular Modeling Studies. ACS chemical neuroscience 19 27499251
2017 Generation and characterization of a human iPSC line from a patient with propionic acidemia due to defects in the PCCA gene. Stem cell research 18 28925364
2017 Propionyl-CoA carboxylase pcca-1 and pccb-1 gene deletions in Caenorhabditis elegans globally impair mitochondrial energy metabolism. Journal of inherited metabolic disease 17 29159707
1987 Propionicacidemia: absence of alpha-chain mRNA in fibroblasts from patients of the pccA complementation group. American journal of human genetics 16 3687944
2012 The GPR88 receptor agonist 2-PCCA does not alter the behavioral effects of methamphetamine in rats. European journal of pharmacology 15 23123351
2008 Array comparative genomic hybridization (aCGH) reveals the largest novel deletion in PCCA found in a Saudi family with propionic acidemia. European journal of medical genetics 14 18790721
2016 Frameshift mutations of OGDH, PPAT and PCCA genes in gastric and colorectal cancers. Neoplasma 13 27468871
2016 Seventeen Novel Mutations in PCCA and PCCB Genes in Indian Propionic Acidemia Patients, and Their Outcomes. Genetic testing and molecular biomarkers 11 27227689
1990 [Histology, immunocytochemistry and DNA cytophotometry of adrenal glandpheochromocytoma (PCC)--a morphologic clinal study of 64 tumors]. Verhandlungen der Deutschen Gesellschaft fur Pathologie 11 1708605
2024 Fasting alleviates metabolic alterations in mice with propionyl-CoA carboxylase deficiency due to Pcca mutation. Communications biology 10 38811689
2002 Transfection screening for defects in the PCCA and PCCB genes encoding propionyl-CoA carboxylase subunits. Molecular genetics and metabolism 8 11914040
2021 Functional Analysis of the PCCA and PCCB Gene Variants Predicted to Affect Splicing. International journal of molecular sciences 6 33923806
2015 [Analysis of PCCA and PCCB gene mutations in patients with propionic acidemia]. Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 6 25636094
2021 Inhibition of selenoprotein synthesis by Zika virus may contribute to congenital Zika syndrome and microcephaly by mimicking SELENOP knockout and the genetic disease PCCA. BBA advances 5 34988542
2018 A Novel PCCA Mutation in a Patient With Late-Onset Propionic Acidemia Identified by Genetic Diagnosis Panel. Frontiers in pediatrics 4 30186825
2024 PCCA variant rs16957301 is a novel AKI risk genotype-specific for patients who receive ICI treatment: Real-world evidence from all of us cohort. European journal of cancer (Oxford, England : 1990) 3 39536432
2020 Case reports: three novel variants in PCCA and PCCB genes in Chinese patients with propionic acidemia. BMC medical genetics 3 32252659
2020 A novel delins (c.773_819+47delinsAA) mutation of the PCCA gene associated with neonatal-onset propionic acidemia: a case report. BMC medical genetics 2 32819290
2017 Physicochemical Stability of an Oral Suspension of Trimethoprim 20 mg/mL in Combination with Sulfadiazine 200 mg/mL in PCCA Base SuspendIt. International journal of pharmaceutical compounding 2 29216620
2025 Silencing PCCA Suppresses CRC Growth and Spread by Modulating EMT and M1 Macrophage Polarization. International journal of medical sciences 1 39744168
2025 Novel CRISPR-Cas9 iPSC knockouts for PCCA and PCCB genes: advancing propionic acidemia research. Human cell 1 40044943
2025 Stability Study of Pediatric Oral Suspensions Formulated with PCCA SuspendIt Vehicle Used for the Treatment of Cardiovascular Disease. International journal of pharmaceutical compounding 1 40961474
2025 LncBADR promotes T cell-mediated autoimmunity by binding Mccc1 and Pcca to regulate BCAAs degradation. Journal of neuroinflammation 1 41013574
2024 The mitochondrial carboxylase PCCA interacts with Listeria monocytogenes phospholipase PlcB to modulate bacterial survival. Applied and environmental microbiology 1 38727222
2023 Identification and characterization of the largest deletion in the PCCA gene causing severe acute early-onset form of propionic acidemia. Molecular genetics and genomics : MGG 1 37131081
2022 Sensitive detection of fusion transcripts with padlock probe-based continuous cascade amplification (P-CCA). The Analyst 1 35466330
2020 Propionic acidemia identified in twin siblings conceived by in vitro fertilization (IVF) with parents who were unknown carriers of a PCCA mutation. BMC pregnancy and childbirth 1 33183246
2026 From N-of-1 to versatility in propionic acidemia: Antisense oligonucleotide-mediated skipping of a constitutive PCCA pseudoexon. Molecular therapy. Nucleic acids 0 42028575
2024 PCCA variant rs16957301 is a novel AKI risk genotype-specific for patients who receive ICI treatment: Real-world evidence from All of Us cohort. medRxiv : the preprint server for health sciences 0 38946978
2024 PPDPF promotes esophageal squamous cell carcinoma progression by blocking PCCA binding to PCCB and inhibiting methionine catabolism. Cancer letters 0 39694223
2022 Development of simple and effective PCR based assay to detect PCCA mutation (c.425G > A) among Saudi carriers and functional study of the homozygous PCCA mutations. Saudi journal of biological sciences 0 36211601

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