| DLST | |
|---|---|
| Gene Symbol | DLST |
| Full Name | Dihydrolipoamide Succinyltransferase |
| Chromosomal Location | 14q24.3 |
| NCBI Gene ID | [1727](https://www.ncbi.nlm.nih.gov/gene/1727) |
| OMIM | [608835](https://www.omim.org/entry/608835) |
| Ensembl ID | ENSG00000135842 |
| UniProt ID | [P36957](https://www.uniprot.org/uniprot/P36957) |
| Associated Diseases | [Parkinson's Disease](/diseases/parkinsons-disease), [Alzheimer's Disease](/diseases/alzheimers-disease), Mitochondrial Disorders |
DLST (Dihydrolipoamide Succinyltransferase) encodes the E2 (dihydrolipoamide succinyltransferase, also known as oxoglutarate dehydrogenase complex subunit E2) component of the alpha-ketoglutarate dehydrogenase complex (α-KGDH), which is a key rate-limiting enzyme in the citric acid cycle (TCA cycle, also known as Krebs cycle). The α-KGDH complex catalyzes the oxidative decarboxylation of α-ketoglutarate to succinyl-CoA, producing NADH and CO2. This reaction is one of the three irreversible steps in the TCA cycle and represents a critical node linking carbon metabolism to oxidative phosphorylation. DLST has been implicated in Parkinson's disease through genome-wide association studies (GWAS), and α-KGDH dysfunction has been strongly linked to neurodegeneration due to its roles in mitochondrial energy production, reactive oxygen species (ROS) generation, and α-ketoglutarate signaling[1][2].
DLST encodes the E2 subunit of the alpha-ketoglutarate dehydrogenase complex (α-KGDH), a pivotal mitochondrial enzyme that catalyzes the third step of the TCA cycle. α-KGDH is widely recognized as a sensitive marker of mitochondrial dysfunction and is implicated in the pathogenesis of Parkinson's disease, Alzheimer's disease, and other neurodegenerative disorders. GWAS have identified DLST variants associated with increased PD risk, highlighting its relevance to disease susceptibility. The enzyme's function is particularly important in energy-demanding dopaminergic neurons of the substantia nigra, which are selectively lost in PD. α-KGDH deficiency leads to impaired energy metabolism, increased oxidative stress, and disrupted α-ketoglutarate signaling, all of which contribute to neuronal death[3][4].
The α-ketoglutarate dehydrogenase complex (α-KGDH) is a large multienzyme complex located in the mitochondrial matrix:
The overall reaction:
α-ketoglutarate + CoA + NAD+ → succinyl-CoA + NADH + CO2
DLST protein properties:
α-KGDH functions in several critical metabolic pathways:
α-KGDH is crucial for mitochondrial ATP production:
The enzyme impacts ROS through:
α-Ketoglutarate serves as:
DLST is genetically and functionally linked to PD:
GWAS associations: DLST variants have been associated with increased PD risk in multiple studies[1:1][5]
Mitochondrial dysfunction: Dopaminergic neurons have high energy demands and are particularly vulnerable to α-KGDH deficiency
α-Synuclein interaction: Impaired α-KGDH may increase neuronal vulnerability to α-synuclein toxicity
Complex I connection: α-KGDH dysfunction compounds complex I deficiency in PD
Therapeutic targeting: Enhancing α-KGDH activity is explored as a neuroprotective strategy[6]
α-KGDH dysfunction in AD:
Energy metabolism deficits: Reduced α-KGDH activity in AD brain contributes to neuronal bioenergetic failure
Oxidative stress: Impaired enzyme function leads to increased oxidative damage
Tau pathology: α-Ketoglutarate-dependent demethylases may affect tau pathology
Amyloid interaction: Aβ may directly inhibit α-KGDH activity
DLST is expressed in most tissues with high energy demands:
In the central nervous system:
| Partner | Relationship | Function |
|---|---|---|
| OGDH (E1) | Complex component | α-ketoglutarate dehydrogenase activity |
| DLDB (E3) | Complex component | Dihydrolipoamide dehydrogenase |
| CoA | Substrate | Co-factor for succinyl-CoA formation |
| NAD+ | Co-substrate | Electron acceptor for NADH production |
| α-Ketoglutarate | Substrate | Primary substrate |
| ATP | Regulator | Allosteric inhibitor |
| ADP | Regulator | Allosteric activator |
Dopaminergic neurons in the substantia nigra pars compacta (SNc) are particularly vulnerable to α-KGDH dysfunction due to several factors[@calingan1999]:
Beyond its role in energy metabolism, α-ketoglutarate serves as an essential co-substrate for:
This positions α-KGDH as a metabolic integrator of cellular state and gene expression[13].
The disruption of α-KGDH creates a metabolic bottleneck:
Multiple large-scale GWAS have identified DLST variants associated with Parkinson's disease risk[1:3][5:2]:
| Study | Population | Effect Size | Risk Allele |
|---|---|---|---|
| Nalls et al. 2013 | European | OR = 1.12 | rs11240572 |
| Koshy et al. 2018 | European | OR = 1.08 | rs7535082 |
Rare DLST variants cause severe neurological disease[14][10:1]:
DLST and α-KGDH activity serve as biomarkers:
Multiple approaches target α-KGDH[13:1][15][16]:
| Enzyme | Gene | Association | Evidence |
|---|---|---|---|
| α-KGDH (E1) | OGDH | PD, AD | Strong[2:2] |
| α-KGDH (E2) | DLST | PD, AD | Strong[1:4] |
| α-KGDH (E3) | DLDB | PD | Moderate |
| PDH | PDHA1 | PD, Leigh syndrome | Strong |
| IDH | IDH1/2 | Glioma, AD | IDH1 in AD |
Dopaminergic neurons of the substantia nigra pars compacta (SNc) face an "energy crisis" that makes them particularly vulnerable to α-KGDH dysfunction. These neurons have high baseline energy demands due to their pacemaking activity, which requires continuous calcium cycling and ATP-dependent ion pumping. The combination of high energy demand and limited compensatory capacity creates a vulnerability threshold[6:2].
When α-KGDH activity is reduced:
Beyond energy production, α-ketoglutarate serves crucial signaling roles:
Epigenetic Regulation:
DNA Methylation:
HIF Regulation:
α-KGDH dysfunction intersects with multiple neurodegenerative pathways:
Protein Aggregation:
Neuroinflammation:
Excitotoxicity:
Rare cases of DLST mutations cause severe neurological disease[10:2]:
Clinical Features:
Biochemical Findings:
Patients with DLST risk variants may represent a distinct PD subgroup:
Characteristics:
Metabolic Support:
Mitochondrial Protectors:
Symptomatic Treatment:
Enzyme Activation:
Substrate Augmentation:
DLST encodes the E2 subunit of α-ketoglutarate dehydrogenase complex, a pivotal enzyme linking TCA cycle function to neuronal survival. GWAS and biochemical studies confirm its role in Parkinson's disease susceptibility and progression. The enzyme's position as a metabolic hub makes it an attractive therapeutic target, though significant work remains to translate these insights into effective treatments.
Nalls MA, et al. Imputation of variants from the 1000 Genomes Project refines GWAS signals and reveals novel loci in Parkinson's disease. Nature Genetics. 2013. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Shi Q, et al. Alpha-ketoglutarate dehydrogenase complex in neurodegenerative disease. Free Radical Biology and Medicine. 2009. ↩︎ ↩︎ ↩︎
Gibson GE, et al. alpha-Ketoglutarate dehydrogenase complex in brain and aging. Journal of Neurochemistry. 2002. ↩︎ ↩︎
Bjoerke ML, et al. Mitochondrial dysfunction in neurodegenerative disease. Biochimica et Biophysica Acta. 2015. ↩︎ ↩︎
Koshy C, et al. DLST variants and Parkinson's disease risk in European populations. Movement Disorders. 2018. ↩︎ ↩︎ ↩︎
Schapira AHV. Mitochondrial dysfunction in Parkinson's disease. Neurochemical Research. 2019. ↩︎ ↩︎ ↩︎
Koike M, et al. alpha-Ketoglutarate dehydrogenase is a novel therapeutic target for neurodegeneration. Journal of Neuroscience. 2012. ↩︎
Tretter L, et al. Alpha-ketoglutarate dehydrogenase complex deficiency in neurodegenerative diseases. Journal of Neural Transmission. 2001. ↩︎
Calingasan NY, et al. Alpha-ketoglutarate dehydrogenase complex in substantia nigra in Parkinson's disease. Journal of Neuropathology & Experimental Neurology. 1999. ↩︎
Postler T, et al. DLST mutations and mitochondrial encephalopathy. Neurology. 2022. ↩︎ ↩︎ ↩︎
Bubber P, et al. Mitochondrial enzymes in Alzheimer's disease. Journal of Neurochemistry. 2005. ↩︎
Kumar MJ, et al. alpha-KGDH and the pathogenesis of neurodegeneration. Brain Research Reviews. 2008. ↩︎
Ma L, et al. Alpha-ketoglutarate dehydrogenase: a target and biomarker for neurodegeneration. CNS Drugs. 2019. ↩︎ ↩︎
Blazquez A, et al. alpha-KGDH deficiency as a cause of severe neurological disease. Human Molecular Genetics. 2019. ↩︎
Patel MS, et al. Alpha-ketoglutarate dehydrogenase: from metabolic enzyme to therapeutic target. Neurochemistry International. 2014. ↩︎ ↩︎
McDonald TS, et al. Alpha-ketoglutarate dehydrogenase: a pivotal mitochondrial enzyme in health and disease. Current Drug Targets. 2017. ↩︎ ↩︎
Chuang JL, et al. Structural basis for the function of DLST in alpha-KGDH complex. Journal of Biological Chemistry. 2004. ↩︎