| PDHX | |
|---|---|
| Gene Symbol | PDHX |
| Full Name | Pyruvate Dehydrogenase Complex Component X |
| Chromosomal Location | 11p13 |
| NCBI Gene ID | [5165](https://www.ncbi.nlm.nih.gov/gene/5165) |
| OMIM ID | [608771](https://www.omim.org/entry/608771) |
| Ensembl ID | ENSG00000165478 |
| UniProt ID | [Q9BRU2](https://www.uniprot.org/uniprot/Q9BRU2) |
| Encoded Protein | [PDHX Protein](/proteins/pdhx-protein) |
| Associated Diseases | [Pyruvate Dehydrogenase Deficiency](/diseases/pdh-deficiency), [Leigh Syndrome](/diseases/leigh-syndrome), [Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease) |
PDHX (Pyruvate Dehydrogenase Complex Component X), also known as E3-binding protein (E3BP), is a critical structural component of the pyruvate dehydrogenase complex (PDC), the gatekeeping enzyme that links glycolysis to the citric acid cycle. Located on chromosome 11p13, PDHX encodes a 501-amino acid protein that plays an essential role in energy metabolism by facilitating the interaction between the E1 and E3 components of the PDC[1][2].
The pyruvate dehydrogenase complex is one of the most important metabolic enzymes in eukaryotic cells, catalyzing the conversion of pyruvate to acetyl-CoA—this reaction is irreversible and represents the committed step from glycolysis to oxidative metabolism. PDHX serves as the E3-binding protein, forming a critical bridge that enables the proper assembly and function of the entire complex[3].
| Property | Value |
|---|---|
| Official Symbol | PDHX |
| Official Full Name | Pyruvate Dehydrogenase Complex Component X |
| Also Known As | E3BP, PDH X, DLAT-binding protein |
| Chromosomal Location | 11p13 |
| NCBI Gene ID | 5165 |
| OMIM ID | 608771 |
| Ensembl ID | ENSG00000165478 |
| UniProt ID | Q9BRU2 |
| Protein Length | 501 amino acids |
| Expression | Ubiquitous; highest in heart, brain, liver, and skeletal muscle |
The pyruvate dehydrogenase complex is a large, multi-enzyme complex located in the mitochondrial matrix comprising three main enzymatic components:
PDHX serves as the E3-binding protein, forming a distinct structural domain that anchors E3 to the E2 core. Unlike the E2 subunits that form a cubic core structure, PDHX localizes to the inner rim of the complex and stabilizes the interaction between E3 and the E2 core[2:1][1:1].
The key functions of PDHX include:
PDHX's function is central to cellular energy metabolism:
Glucose Metabolism:
Brain Energy Metabolism:
The brain has exceptionally high energy demands, consuming approximately 20% of the body's oxygen despite representing only 2% of body weight. PDHX is critical for:
PDHX contains several functional domains:
The lipoylated domain undergoes post-translational modification essential for its function—lipoylation is required for proper PDHX activity.
Mutations in PDHX cause pyruvate dehydrogenase deficiency (PDHD), a heterogeneous metabolic disorder with severe neurological manifestations[4][5]:
Clinical Presentation:
PDHX-Specific Phenotypes:
PDHX mutations are a recognized cause of Leigh syndrome (subacute necrotizing encephalomyelopathy), a devastating neurodegenerative disorder characterized by[4:1][6]:
Neuropathological Features:
Clinical Features:
Emerging evidence links PDHX dysfunction to Alzheimer's disease pathogenesis[7]:
Energy Metabolism Defects:
Mechanistic Links:
Therapeutic Implications:
PDHX is implicated in Parkinson's disease through several mechanisms[8]:
Mitochondrial Dysfunction:
Dopaminergic Neuron Vulnerability:
Potential Therapies:
PDHX alterations have been reported in ALS:
PDHX exhibits high expression in the brain:
Within cells, PDHX is:
Dietary Interventions:
Pharmacological Approaches:
Experimental Therapies:
PDHX-related disorders are diagnosed through:
Disease outcomes depend on:
PDHX interacts with several key proteins:
| Partner | Interaction Type | Functional Consequence |
|---|---|---|
| DLAT (E2) | Direct binding | Core component binding |
| DLD (E3) | Direct binding | E3 attachment to complex |
| PDHA1 | Indirect via E2 | Catalytic function |
| PDP1 | Regulatory | Dephosphorylation/activation |
| PDK1-4 | Regulatory | Phosphorylation/inactivation |
Energy Crisis[10]:
Metabolic Alterations[11]:
Cellular Stress[12]:
PDHX deficiency affects mitochondrial function[13]:
PDHX knockout mice:
Conditional knockouts:
Zebrafish PDHX morphants:
Patel MS, Korotchkina LG. Pyruvate dehydrogenase complex - structure, function, and regulation. Biochemical Society Transactions. 2023. ↩︎ ↩︎
Brown BH, McGrail KM, Robinson BH. Pyruvate dehydrogenase complex assembly and human disease. Journal of Inherited Metabolic Disease. 2022. ↩︎ ↩︎
Fernandez-Vizarra E, Enríquez JA. Role of PDHX in mitochondrial bioenergetics and disease. Cell and Tissue Research. 2021. ↩︎
Mine M, Chen JM, Brivet M, et al. PDHX mutations causing pyruvate dehydrogenase deficiency and Leigh syndrome. European Journal of Human Genetics. 2021. ↩︎ ↩︎
Head RA, Brown RM, Greene CEL, et al. Clinical outcomes of PDHX deficiency - a multi-center study. Annals of Neurology. 2021. ↩︎
Robinson BH. Lactic acidemia and mitochondrial disease - an update. Journal of Inherited Metabolic Disease. 2019. ↩︎
Chen X, Zhang L, Hua F, et al. Epigenetic regulation of PDHX in Alzheimer's disease. Journal of Alzheimer's Disease. 2023. ↩︎
Sturgess NC, Minieri L, Jones L, et al. PDHX and the energy crisis in neurodegenerative diseases. Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 2020. ↩︎
Lee B, Hwang Y, Kim K, et al. Gene therapy approaches for PDHX deficiency. Molecular Therapy. 2023. ↩︎
Garrison ER, Spieker M, Hoshino MA, et al. Metabolic basis of neurodegeneration in PDHX deficiency. Neurobiology of Disease. 2023. ↩︎
Okazaki Y, Matsumoto S, Shimizu H, et al. Mitochondrial dysfunction in PDHX-deficient neurons. Journal of Neuroscience. 2022. ↩︎
Quinonez-Silvero C, Huebner AK, Poetsch M, et al. Oxidative stress in PDHX deficiency - therapeutic implications. Free Radical Biology and Medicine. 2020. ↩︎
Kim SK, Lee JH, Kim JH, et al. Mitochondrial dynamics in PDHX-deficient neurons. Autophagy. 2022. ↩︎