OGDHL

OGDHL is a rate-limiting component of the α-ketoglutarate dehydrogenase complex (OGDHC) whose loss reduces OGDHC activity, raising the α-ketoglutarate:citrate ratio and driving reductive carboxylation of glutamine-derived αKG, which activates mTORC1-dependent de novo lipogenesis (PMID:31899205). Its catalytic role supports normal mitochondrial respiration, and loss-of-function impairs oxygen consumption in epithelial and neuronal cells (PMID:29669943, PMID:34800363). Bi-allelic OGDHL variants cause a Mendelian neurodevelopmental disorder: pan-neuronal knockout of the Drosophila ortholog produces lethality and Krebs cycle defects rescued by wild-type cDNA, while human patient missense variants segregate into severe loss-of-function and hypomorphic alleles by complementation in fly and zebrafish models (PMID:34800363, PMID:38031187). As a metabolic gatekeeper, OGDHL loss reprograms tumor metabolism along several axes: accumulation of L-2-hydroxyglutarate inhibits prolyl hydroxylases to stabilize HIF-1α and drive EMT and metastasis (PMID:36000493); suppression by FTO-mediated m6A demethylation stabilizes TFAP2A to transcriptionally activate FASN and promote lipid accumulation and ERK signaling (PMID:37626053); and forced expression elevates ROS to engage caspase-3, downregulating AKT and NF-κB signaling (PMID:23152800). OGDHL physically interacts with PDHB, stabilizing it to sustain pyruvate oxidative decarboxylation and acetyl-CoA/ATP production (PMID:41420718). An extra-mitochondrial role is also evident: in prostate cancer OGDHL supports nucleotide synthesis and neuroendocrine lineage plasticity independently of mitochondrial localization (PMID:41591383).

1. 2012 Medium

   Established that OGDHL can act as a tumor suppressor by linking its expression to a ROS-driven apoptotic signaling cascade, the first functional handle beyond presumed metabolic activity.

   Evidence Overexpression and shRNA knockdown in cervical cancer cells with ROS, caspase-3, and phospho-AKT/NF-κB readouts plus inhibitor rescue

   PMID:23152800

   Open questions at the time

   • Mechanism connecting OGDHL enzymatic activity to ROS generation not defined
   • Single cancer cell context
   • No in vitro reconstitution of the proposed pathway
2. 2018 Medium

   Demonstrated that OGDHL is required for normal mitochondrial respiration, grounding its cellular role in oxidative metabolism.

   Evidence shRNA knockdown in esophageal epithelial cells and patient fibroblasts with respirometry

   PMID:29669943

   Open questions at the time

   • Limited mechanistic depth
   • Does not resolve which respiratory step is affected
   • Single lab
3. 2019 High

   Defined the core metabolic consequence of OGDHL loss: reduced OGDHC activity raises the αKG:citrate ratio, driving reductive glutamine carboxylation and mTORC1-dependent lipogenesis.

   Evidence Overexpression/knockdown in hepatoma cells and xenografts with OGDHC activity assays, isotope tracing, metabolite profiling and pathway immunoblotting

   PMID:31899205

   Open questions at the time

   • Direct enzymatic kinetics of OGDHL not characterized
   • Tissue specificity of the mTORC1 link unclear
4. 2021 High

   Established OGDHL as a Mendelian neurodevelopmental disease gene and confirmed allele-specific severity through cross-species rescue.

   Evidence CRISPR knockout of Drosophila dOgdh with cDNA rescue, patient variant mutagenesis, and human neuronal knockout respirometry across multiple families

   PMID:34800363

   Open questions at the time

   • Biochemical defect of individual variants not measured directly
   • Neuronal cell-type vulnerability not resolved
5. 2021 Low

   Probed whether OGDHL is neuroprotective in neurodegeneration models, linking it to Wnt/β-catenin signaling.

   Evidence OGDHL overexpression in 3×Tg-AD mice with histology, behavior, and Wnt7B expression in vitro

   PMID:34798170

   Open questions at the time

   • Single pathway marker per readout, mechanism not established
   • Causal link between OGDHL and Wnt signaling unproven
   • Not independently confirmed
6. 2022 Low

   Attempted to link a common OGDHL variant to brain glutamate accumulation via predicted cofactor-binding disruption.

   Evidence Whole-exome sequencing with computational conformational modeling of the transketolase domain and brain imaging

   PMID:35370858

   Open questions at the time

   • No in vitro validation of altered TPP binding
   • Causality between variant and phenotype not demonstrated
   • Mechanism purely computational
7. 2023 Medium

   Connected OGDHL loss to oncogenic metabolic rewiring through distinct mechanisms: HIF-1α stabilization via L-2-HG and FASN induction via TFAP2A under FTO/m6A control.

   Evidence OGDHL OE/KD in HCC and ccRCC with L-2-HG measurement, HIF-1α stability assays, MeRIP, ChIP, luciferase, ubiquitination and in vivo metastasis models

   PMID:36000493 PMID:37626053

   Open questions at the time

   • Each axis shown in a single cancer type
   • Direct demonstration that OGDHC activity loss produces L-2-HG not fully resolved
   • Single lab per mechanism
8. 2023 Medium

   Clarified paralog compensation and allele-specific enzyme function among OGDHL, OGDH, and DHTKD1, refining genotype–phenotype interpretation.

   Evidence CRISPR zebrafish knockouts of ogdhl and paralogs with human patient-variant cDNA complementation and developmental phenotyping

   PMID:38031187

   Open questions at the time

   • Degree of redundancy in human tissues unknown
   • Enzyme-level kinetics inferred, not directly measured
9. 2025 Medium

   Identified PDHB as a direct physical partner of OGDHL, extending its influence to pyruvate oxidative decarboxylation.

   Evidence Co-IP in gastric cancer cells with PDHB stability, acetyl-CoA/ATP measurement and in vivo tumor models

   PMID:41420718

   Open questions at the time

   • Single Co-IP without reciprocal validation
   • Mechanism of PDHB stabilization undefined
   • Single cancer context
10. 2025 Medium

    Revealed an extra-mitochondrial function for OGDHL in supporting nucleotide synthesis and neuroendocrine lineage plasticity, decoupling some roles from its canonical mitochondrial localization.

    Evidence OGDHL knockdown in prostate cancer cells and xenografts with nucleotide profiling, γH2AX, neuroendocrine markers, and mitochondrial localization mutant constructs

    PMID:41591383

    Open questions at the time

    • Molecular basis of the extra-mitochondrial activity unknown
    • Direct biochemical substrate in this context not identified
    • Single lab

• How OGDHL is targeted to mitochondria versus retained for extra-mitochondrial functions, and the direct biochemical activity underlying its non-canonical roles, remain unresolved.
• No structural model of human OGDHL enzyme validated experimentally
• Mechanism of subcellular partitioning unestablished
• Direct kinetic characterization of OGDHL catalysis absent from the corpus