{"gene":"PDK2","run_date":"2026-06-10T05:19:53","timeline":{"discoveries":[{"year":2011,"finding":"Wild-type p53 directly represses transcription of PDK2, thereby reducing inactive phosphorylated pyruvate dehydrogenase complex (P-PDC) and limiting conversion of pyruvate to lactate (Warburg effect). Loss of p53 allows PDK2 elevation and promotes aerobic glycolysis.","method":"p53 knockdown/overexpression in cancer cells, Western blot for PDK2 and P-PDC, lactate measurement","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — defined transcriptional mechanism with functional metabolic readout, single lab with two orthogonal methods","pmids":["22123926"],"is_preprint":false},{"year":2003,"finding":"AZD7545, a small-molecule inhibitor of PDK2, activates PDH in vitro (EC50 ~5.2 nM in presence of PDK2) and in vivo, increasing the dephosphorylated (active) form of PDH in liver and skeletal muscle of rats and improving blood glucose control in obese Zucker rats.","method":"In vitro PDH activity assay with AZD7545 and PDK2; in vivo dosing in Wistar and obese Zucker rats; PDH activity measurement in tissue","journal":"Biochemical Society transactions","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro enzymatic inhibition assay with defined EC50, replicated in vivo in multiple animal models","pmids":["14641018"],"is_preprint":false},{"year":2012,"finding":"PDHK2 (PDK2) knockout in mice increases PDH complex activity and lowers blood glucose in the fed state. Double knockout of PDHK2 and PDHK4 causes hypoglycaemia, ketoacidosis and hypothermia during fasting, establishing that PDK2 is the dominant regulator of PDH complex in the fed state while PDK4 dominates in the fasted state.","method":"Single and double PDK2/PDK4 knockout mice; PDH complex activity assays; blood glucose, insulin, and ketone measurements; stable isotope flux analysis","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — genetic knockout with multiple orthogonal metabolic readouts in vivo, replicated across single and double KO conditions","pmids":["22360721"],"is_preprint":false},{"year":2017,"finding":"PDK2 phosphorylates the mitochondrial rhomboid protease PARL, regulating its N-terminal autocatalytic β-cleavage. PDK2-mediated phosphorylation of PARL negatively regulates PINK1/PARKIN-mediated mitophagy by controlling production of the less-active PARL cleavage product PACT, integrating mitochondrial metabolism with mitochondrial quality control.","method":"Co-IP; phosphorylation assays; mitochondrial stress assays; PARL cleavage Western blot; mitophagy reporters","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct phosphorylation substrate identified with functional mitophagy readout, single lab with multiple orthogonal methods","pmids":["28178523"],"is_preprint":false},{"year":2008,"finding":"PDK2 binds the L2 lipoyl domain (E2 subunit of PDC) via a site stimulated by K+ ions at a site distinct from the ATP active site. Phosphate (Pi) is required for ADP, ATP, or pyruvate to interfere with PDK2 binding to L2 and promotes PDK2 tetramer formation. The acetyl-lipoate analog Nov3r inhibits E2-activated PDK2 (IC50 ~7.8 nM) by occupying the lipoyl-group binding site and preventing PDK2 binding to E2.","method":"Biochemical binding assays (PDHK2 and GST-L2 interaction), kinase activity assays, gel filtration for oligomeric state","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with kinetic characterization, mutagenesis/ligand competition, defined binding sites","pmids":["18220415"],"is_preprint":false},{"year":2020,"finding":"Crystal structures of PDK2 in complex with inhibitor compound 8c (at the lipoyl-binding site) and novel 4,5-diarylisoxazole derivatives GM10030/GM67520 (at the ATP-binding site) reveal remote conformational coupling between the lipoyl-binding pocket and the ATP-binding pocket, and demonstrate an unprecedented asymmetric dimer conformation of PDK2.","method":"X-ray crystallography of PDK2 co-crystal structures; isothermal titration calorimetry for binding affinity","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structures with ITC binding validation, multiple compounds confirming two binding sites","pmids":["32444142"],"is_preprint":false},{"year":2024,"finding":"PDK2 directly phosphorylates the transcription factor FOXK2 at Thr13 and Ser30 via interaction with the FOXK2 forkhead-associated (FHA) domain, enhancing FOXK2 transcriptional activity. FOXK2 in turn transcriptionally upregulates PDK2, creating a positive feedback loop that sustains glycolysis in ovarian cancer cells.","method":"Co-IP, in vitro kinase assay, site-directed mutagenesis of FOXK2 phosphorylation sites, luciferase reporter for PDK2 promoter, xenograft assay","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — direct substrate phosphorylation identified with mutagenesis and co-IP, positive feedback loop confirmed by reporter assay, single lab","pmids":["38734828"],"is_preprint":false},{"year":2024,"finding":"OGT-catalyzed O-GlcNAc modification of c-Myc at Ser415 stabilizes c-Myc protein, which transcriptionally upregulates PDK2 expression. Elevated PDK2 then phosphorylates the E1α subunit of the pyruvate dehydrogenase complex (PDH), inhibiting PDH activity, reducing mitochondrial pyruvate metabolism, suppressing ROS, and promoting xenograft tumor growth.","method":"OGT depletion, c-Myc glycosylation site mutagenesis (S415A), ChIP, PDH phosphorylation assays, xenograft models","journal":"Cell death and differentiation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multi-step pathway placed by genetic and biochemical methods, site-directed mutagenesis and ChIP, single lab","pmids":["38778217"],"is_preprint":false},{"year":2023,"finding":"Glucocorticoid receptor (GR) directly binds the PDK2 promoter and stimulates PDK2 transcription in neurons in response to elevated glucocorticoids (GCs). Elevated PDK2 phosphorylates and inhibits PDH, reducing mitochondrial oxidative phosphorylation and TCA cycle flux. Silencing PDK2 abrogated glucocorticoid-induced PDH inhibition and restored neuronal oxidative phosphorylation.","method":"ChIP of GR at PDK2 promoter, PDK2 shRNA/siRNA knockdown, PDH phosphorylation Western blot, U-13C glucose isotope tracing, in vivo GR/PDK2 silencing with behavioral readout","journal":"Molecular psychiatry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct promoter binding by ChIP, isotope flux analysis, genetic loss-of-function, single lab","pmids":["37188779"],"is_preprint":false},{"year":2019,"finding":"PDK2 mediates alternative pre-mRNA splicing of Bnip3 in cancer cells: inhibition of PDK2 in Panc-1 cells rapidly shifts Bnip3 isoform balance from the survival truncated Bnip3Δex3 toward the pro-death full-length Bnip3FL, inducing mitochondrial perturbations and cell death, coupling the glycolytic phenotype to hypoxia resistance.","method":"PDK2 inhibition (siRNA/DCA), RT-PCR isoform analysis, mitochondrial membrane potential assay, cell death assays","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined molecular splicing readout, single lab with two methods","pmids":["26416963"],"is_preprint":false},{"year":2020,"finding":"PDK2 deficiency (genetic knockout and pharmacological inhibition with AZD7545) suppresses osteoclast differentiation by reducing phosphorylation of CREB and c-FOS, and consequent NFATc1 transcription downstream of RANKL signaling, thereby preventing ovariectomy-induced bone loss in mice.","method":"PDK2 knockout mice, PDK2 inhibitor AZD7545, ovariectomy model, CREB/c-FOS/NFATc1 Western blot, osteoclast differentiation assays from bone marrow cells","journal":"Journal of bone and mineral research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO and pharmacological inhibition with defined signaling pathway readout, single lab","pmids":["33125772"],"is_preprint":false},{"year":2021,"finding":"PDK2 inhibition in ischemia/reperfusion injury increases PDH activity through the PDK2-PDH-Nrf2 axis: DCA-mediated PDK2 inhibition activates PDH, promotes glycolytic flux into the TCA cycle, and elevates Nrf2 and HO-1 antioxidant proteins, reducing oxidative stress and blood-brain barrier damage.","method":"MCAO mouse model, OGD in vitro model, DCA treatment, Western blot for PDK2/PDH/Nrf2/HO-1, Nrf2-specific inhibitor ML385 rescue experiment","journal":"Oxidative medicine and cellular longevity","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological inhibition with genetic inhibitor rescue in vivo and in vitro, single lab, multiple orthogonal readouts","pmids":["34712383"],"is_preprint":false},{"year":2023,"finding":"Oroxylin A (OA) disrupts the SIRT1/PDK2/PARL axis, inhibiting mitochondrial fusion; this synergizes with GLUT1 inhibition to break mitochondrial metabolic plasticity and sensitize hepatocellular carcinoma cells to glucose restriction.","method":"Pharmacological treatment with OA, mitochondrial fusion assays, spare respiratory capacity measurement, Western blot for SIRT1/PDK2/PARL","journal":"Biomedicine & pharmacotherapy","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pathway placement inferred from pharmacological compound without direct PDK2 biochemical validation, single lab","pmids":["37633053"],"is_preprint":false},{"year":2012,"finding":"In C. elegans, PDHK-2 (PDK2 ortholog) expression is regulated by DAF-16 and NHR-49 transcription factors and is induced during long-term starvation and dauer state. PDHK-2 deficiency preserves fat stores by reducing lipase (ATGL, HSL) expression, extending dauer survival under nutrient restriction.","method":"C. elegans genetic mutants (pdhk-2 loss-of-function alleles), fat staining, lipase gene expression, survival assays, genetic epistasis with daf-2","journal":"PloS one","confidence":"Low","confidence_rationale":"Tier 3 / Weak — C. elegans ortholog with genetic epistasis, single lab, lipase connection indirect","pmids":["22848591"],"is_preprint":false},{"year":2011,"finding":"Chronic cigarette smoke extract (CSE) treatment upregulates PDK2 expression in oral keratinocytes, decreasing PDH activity and increasing pyruvate and lactate production. This promotes HIF1α accumulation; ROS scavengers abolish PDK2 and HIF1α induction, and PDK2 inhibition with DCA reduces HIF1α and cell proliferation.","method":"PDK2 expression by qRT-PCR/Western blot, PDH activity assay, lactate/pyruvate measurement, HIF1α Western blot, DCA and N-acetylcysteine treatment, HIF1α inhibitor","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological inhibition plus enzymatic activity assay with multiple metabolic readouts, single lab","pmids":["21283817"],"is_preprint":false},{"year":2019,"finding":"PDK2 promotes cisplatin resistance in lung adenocarcinoma via transcriptional upregulation of CNNM3. PDK2 knockdown reduces CNNM3 expression and restores cisplatin sensitivity in vitro and in vivo.","method":"PDK2 overexpression/knockdown, CNNM3 luciferase reporter, cisplatin resistance assays, xenograft models","journal":"Journal of drug targeting","confidence":"Low","confidence_rationale":"Tier 3 / Weak — transcriptional regulation inferred from reporter and KD, mechanism of PDK2 acting as transcriptional regulator not fully characterized, single lab","pmids":["30457021"],"is_preprint":false},{"year":2020,"finding":"PDK2 overexpression in thyroid-associated ophthalmopathy (TAO) orbital fibroblasts enhances glycolysis (increased lactate, decreased oxygen consumption) and promotes fibroblast proliferation. PDK2 knockdown reduces cytoplasmic Akt levels and proliferation in TAO cells, placing PDK2 upstream of Akt signaling in this context.","method":"PDK2 siRNA knockdown, lactate production assay, oxygen consumption assay, Akt/pAkt308 quantification by capillary Western, EdU/BrdU proliferation assays","journal":"Journal of molecular endocrinology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — KD with metabolic and proliferation readouts, Akt link is correlative, single lab","pmids":["33086191"],"is_preprint":false}],"current_model":"PDK2 (pyruvate dehydrogenase kinase isoform 2) is a mitochondrial kinase that phosphorylates and inactivates the E1α subunit of the pyruvate dehydrogenase complex (PDC), reducing conversion of pyruvate to acetyl-CoA and promoting aerobic glycolysis; its activity is stimulated by E2-subunit lipoyl domain binding (regulated by K⁺ and Pi), inhibited by compounds occupying either the ATP-binding or lipoyl-group binding site, transcriptionally induced by p53 loss, glucocorticoid receptor, and c-Myc O-GlcNAcylation; it also phosphorylates non-PDC substrates including PARL (regulating mitophagy) and FOXK2 (sustaining a glycolytic positive feedback loop), and genetic knockout in mice establishes PDK2 as the dominant PDH complex regulator in the fed state."},"narrative":{"mechanistic_narrative":"PDK2 is a mitochondrial kinase that phosphorylates and inactivates the E1α subunit of the pyruvate dehydrogenase complex (PDC), throttling conversion of pyruvate to acetyl-CoA and shifting cells toward aerobic glycolysis [PMID:38778217]. Genetic knockout studies establish PDK2 as the dominant regulator of PDC activity in the fed state, with loss raising PDC activity and lowering blood glucose, while combined PDK2/PDK4 deletion produces fasting hypoglycaemia and ketoacidosis [PMID:22360721]. Its kinase activity is allosterically governed by binding to the L2 lipoyl domain of the PDC E2 subunit, a site stimulated by K+ ions and dependent on inorganic phosphate, which also promotes PDK2 tetramerization and renders the enzyme sensitive to lipoyl-site occupancy; pharmacological and structural work defines two distinct druggable pockets—an ATP-binding active site (AZD7545, diarylisoxazoles) and a lipoyl-group binding site (Nov3r, compound 8c)—that are conformationally coupled across an asymmetric PDK2 dimer [PMID:14641018, PMID:18220415, PMID:32444142]. PDK2 expression is transcriptionally elevated by loss of wild-type p53, by glucocorticoid receptor binding to the PDK2 promoter, and by O-GlcNAc-stabilized c-Myc, in each case suppressing PDH-driven oxidative metabolism in cancer cells and neurons [PMID:22123926, PMID:38778217, PMID:37188779]. Beyond the PDC, PDK2 phosphorylates the mitochondrial rhomboid protease PARL to restrain PINK1/PARKIN-dependent mitophagy [PMID:28178523] and phosphorylates the transcription factor FOXK2 at Thr13/Ser30 via its FHA domain, establishing a FOXK2–PDK2 positive feedback loop that sustains glycolysis [PMID:38734828]. Through these activities PDK2 couples mitochondrial pyruvate flux to redox balance and pathological phenotypes, including tumor growth, ischemia/reperfusion injury via a PDK2-PDH-Nrf2 antioxidant axis, and RANKL-driven osteoclast differentiation and bone loss [PMID:33125772, PMID:34712383].","teleology":[{"year":2003,"claim":"Established PDK2 as a tractable pharmacological target whose inhibition reactivates PDH and improves systemic glucose handling, defining the enzyme's metabolic switch role in vivo.","evidence":"In vitro PDH activity assay with the inhibitor AZD7545 (EC50 ~5.2 nM) and in vivo dosing in Wistar and obese Zucker rats","pmids":["14641018"],"confidence":"High","gaps":["Does not resolve isoform selectivity of AZD7545 across PDK1-4","No structural basis for inhibition provided at this stage"]},{"year":2008,"claim":"Defined the allosteric architecture of PDK2 regulation by showing lipoyl-domain (L2/E2) binding, K+ and phosphate dependence, and a distinct lipoyl-group inhibitory pocket separate from the ATP site.","evidence":"Biochemical binding assays of PDHK2 with GST-L2, kinase activity assays, gel filtration for oligomeric state, ligand competition with Nov3r (IC50 ~7.8 nM)","pmids":["18220415"],"confidence":"High","gaps":["Atomic structure of the two binding sites not yet resolved here","Physiological trigger for tetramer formation in vivo unclear"]},{"year":2011,"claim":"Connected PDK2 to tumor metabolism by identifying wild-type p53 as a direct transcriptional repressor whose loss elevates PDK2 and drives the Warburg effect.","evidence":"p53 knockdown/overexpression in cancer cells, Western blot for PDK2 and phospho-PDC, lactate measurement","pmids":["22123926"],"confidence":"Medium","gaps":["Direct p53 binding element on PDK2 promoter not mapped","Single-lab transcriptional mechanism"]},{"year":2011,"claim":"Placed PDK2 in a redox-responsive feed-forward loop with HIF1α, showing carcinogen-induced ROS upregulates PDK2 to sustain glycolysis and HIF1α accumulation.","evidence":"PDK2 qRT-PCR/Western blot, PDH activity and lactate/pyruvate assays, HIF1α blots, DCA and N-acetylcysteine treatment in oral keratinocytes","pmids":["21283817"],"confidence":"Medium","gaps":["Whether ROS acts on PDK2 transcription directly or via an intermediate is unresolved","Single cell-type context"]},{"year":2012,"claim":"Genetic knockout established PDK2 as the dominant physiological regulator of PDC in the fed state, distinguishing its role from PDK4's fasting dominance.","evidence":"Single and double PDK2/PDK4 knockout mice; PDC activity assays; blood glucose, insulin, ketone, and stable-isotope flux measurements","pmids":["22360721"],"confidence":"High","gaps":["Tissue-specific contributions not dissected","Does not address non-PDC substrate functions in vivo"]},{"year":2017,"claim":"Extended PDK2 substrate scope beyond the PDC by identifying PARL phosphorylation as a link between mitochondrial metabolism and mitophagy.","evidence":"Co-IP, phosphorylation assays, PARL cleavage Western blot, mitophagy reporters under mitochondrial stress","pmids":["28178523"],"confidence":"Medium","gaps":["Phosphosite on PARL not pinpointed","Single-lab finding without reciprocal validation"]},{"year":2019,"claim":"Implicated PDK2 in coupling glycolytic phenotype to hypoxia/apoptosis resistance through Bnip3 alternative splicing.","evidence":"PDK2 inhibition (siRNA/DCA), RT-PCR isoform analysis, mitochondrial membrane potential and cell-death assays in Panc-1 cells","pmids":["26416963"],"confidence":"Medium","gaps":["Mechanism linking a mitochondrial kinase to nuclear splicing not defined","No direct splicing-factor target identified"]},{"year":2020,"claim":"Provided structural proof of two coupled drug-binding pockets and an asymmetric PDK2 dimer, rationalizing allosteric inhibition.","evidence":"X-ray co-crystal structures with compound 8c (lipoyl site) and diarylisoxazoles GM10030/GM67520 (ATP site); ITC binding validation","pmids":["32444142"],"confidence":"High","gaps":["Conformational coupling shown structurally but not kinetically dissected","Dimer asymmetry functional consequence in vivo unknown"]},{"year":2020,"claim":"Linked PDK2 activity to RANKL-driven osteoclastogenesis and bone homeostasis, broadening its physiological role beyond glucose metabolism.","evidence":"PDK2 knockout mice and AZD7545 inhibition, ovariectomy model, CREB/c-FOS/NFATc1 blots, osteoclast differentiation assays","pmids":["33125772"],"confidence":"Medium","gaps":["How PDH/metabolic flux feeds into CREB/c-FOS signaling not mechanistically resolved","Single-lab study"]},{"year":2021,"claim":"Defined a PDK2-PDH-Nrf2 antioxidant axis governing oxidative stress and blood-brain barrier integrity in ischemia/reperfusion.","evidence":"MCAO and OGD models, DCA inhibition, Nrf2/HO-1 blots, ML385 Nrf2-inhibitor rescue","pmids":["34712383"],"confidence":"Medium","gaps":["Reliance on pharmacological DCA rather than genetic PDK2 loss","Direct vs metabolic-flux-mediated Nrf2 induction not separated"]},{"year":2023,"claim":"Identified glucocorticoid receptor as a direct transcriptional driver of PDK2 in neurons, suppressing oxidative phosphorylation in response to glucocorticoids.","evidence":"ChIP of GR at PDK2 promoter, PDK2 knockdown, PDH phosphorylation blots, U-13C glucose tracing, in vivo silencing with behavioral readout","pmids":["37188779"],"confidence":"Medium","gaps":["GR binding element sequence not defined","Single-lab neuronal context"]},{"year":2024,"claim":"Revealed a c-Myc–PDK2 transcriptional input controlled by O-GlcNAcylation, linking nutrient-sensing post-translational modification to PDH suppression and tumor growth.","evidence":"OGT depletion, c-Myc S415A glycosylation-site mutagenesis, ChIP, PDH phosphorylation assays, xenograft models","pmids":["38778217"],"confidence":"Medium","gaps":["Direct c-Myc occupancy element on PDK2 promoter not mapped beyond ChIP","Single-lab pathway"]},{"year":2024,"claim":"Identified FOXK2 as a direct PDK2 phosphorylation substrate forming a glycolytic positive feedback loop, the first transcription-factor substrate establishing reciprocal PDK2 regulation.","evidence":"Co-IP, in vitro kinase assay, FOXK2 Thr13/Ser30 mutagenesis, PDK2 promoter luciferase reporter, xenograft assay in ovarian cancer","pmids":["38734828"],"confidence":"Medium","gaps":["Structural basis of FHA-domain recognition not solved","Loop dynamics in non-cancer cells untested"]},{"year":null,"claim":"How PDK2's distinct activities—PDC inactivation versus non-canonical substrate phosphorylation (PARL, FOXK2) and reported transcriptional/proliferative effects—are coordinated, and which are druggable independently, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model reconciling mitochondrial kinase activity with apparent transcriptional/splicing influence","Substrate phosphosite specificity determinants undefined","Isoform-selective therapeutic exploitation not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[3,6,7]},{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[1,4,7]},{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[4,5]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[3,7]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[1,2,7]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[3]}],"complexes":[],"partners":["PDHA1","PARL","FOXK2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q15119","full_name":"[Pyruvate dehydrogenase (acetyl-transferring)] kinase isozyme 2, mitochondrial","aliases":["Pyruvate dehydrogenase kinase isoform 2","PDH kinase 2","PDKII"],"length_aa":407,"mass_kda":46.2,"function":"Kinase that plays a key role in the regulation of glucose and fatty acid metabolism and homeostasis via phosphorylation of the pyruvate dehydrogenase subunits PDHA1 and PDHA2. This inhibits pyruvate dehydrogenase activity, and thereby regulates metabolite flux through the tricarboxylic acid cycle, down-regulates aerobic respiration and inhibits the formation of acetyl-coenzyme A from pyruvate. Inhibition of pyruvate dehydrogenase decreases glucose utilization and increases fat metabolism. Mediates cellular responses to insulin. Plays an important role in maintaining normal blood glucose levels and in metabolic adaptation to nutrient availability. Via its regulation of pyruvate dehydrogenase activity, plays an important role in maintaining normal blood pH and in preventing the accumulation of ketone bodies under starvation. Plays a role in the regulation of cell proliferation and in resistance to apoptosis under oxidative stress. Plays a role in p53/TP53-mediated apoptosis","subcellular_location":"Mitochondrion matrix","url":"https://www.uniprot.org/uniprotkb/Q15119/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PDK2","classification":"Not Classified","n_dependent_lines":144,"n_total_lines":1208,"dependency_fraction":0.11920529801324503},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/PDK2","total_profiled":1310},"omim":[{"mim_id":"618713","title":"CYSTIN 1; CYS1","url":"https://www.omim.org/entry/618713"},{"mim_id":"604683","title":"KINESIN FAMILY MEMBER 3A; KIF3A","url":"https://www.omim.org/entry/604683"},{"mim_id":"602958","title":"SERUM/GLUCOCORTICOID-REGULATED KINASE 1; SGK1","url":"https://www.omim.org/entry/602958"},{"mim_id":"602527","title":"PYRUVATE DEHYDROGENASE KINASE, ISOENZYME 4; PDK4","url":"https://www.omim.org/entry/602527"},{"mim_id":"602525","title":"PYRUVATE DEHYDROGENASE KINASE, ISOENZYME 2; PDK2","url":"https://www.omim.org/entry/602525"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Mitochondria","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"skeletal muscle","ntpm":202.5},{"tissue":"tongue","ntpm":265.8}],"url":"https://www.proteinatlas.org/search/PDK2"},"hgnc":{"alias_symbol":["PDHK2"],"prev_symbol":[]},"alphafold":{"accession":"Q15119","domains":[{"cath_id":"1.20.140.20","chopping":"1-189","consensus_level":"medium","plddt":90.1367,"start":1,"end":189},{"cath_id":"3.30.565.10","chopping":"191-360","consensus_level":"high","plddt":91.8619,"start":191,"end":360}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q15119","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q15119-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q15119-F1-predicted_aligned_error_v6.png","plddt_mean":90.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PDK2","jax_strain_url":"https://www.jax.org/strain/search?query=PDK2"},"sequence":{"accession":"Q15119","fasta_url":"https://rest.uniprot.org/uniprotkb/Q15119.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q15119/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q15119"}},"corpus_meta":[{"pmid":"10191262","id":"PMC_10191262","title":"Activation of serum- and glucocorticoid-regulated protein kinase by agonists that activate phosphatidylinositide 3-kinase is mediated by 3-phosphoinositide-dependent protein kinase-1 (PDK1) and PDK2.","date":"1999","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/10191262","citation_count":496,"is_preprint":false},{"pmid":"10722653","id":"PMC_10722653","title":"Akt/protein kinase B is regulated by autophosphorylation at the hypothetical PDK-2 site.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10722653","citation_count":420,"is_preprint":false},{"pmid":"10226025","id":"PMC_10226025","title":"PDK1 acquires PDK2 activity in the presence of a synthetic peptide derived from the carboxyl terminus of PRK2.","date":"1999","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/10226025","citation_count":384,"is_preprint":false},{"pmid":"22123926","id":"PMC_22123926","title":"p53 negatively regulates transcription of the pyruvate dehydrogenase kinase Pdk2.","date":"2011","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/22123926","citation_count":207,"is_preprint":false},{"pmid":"16014356","id":"PMC_16014356","title":"PDK2: the missing piece in the receptor tyrosine kinase signaling pathway puzzle.","date":"2005","source":"American journal of physiology. 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Osteoclastogenesis.","date":"2020","source":"Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research","url":"https://pubmed.ncbi.nlm.nih.gov/33125772","citation_count":22,"is_preprint":false},{"pmid":"28225870","id":"PMC_28225870","title":"PDK2 promotes chondrogenic differentiation of mesenchymal stem cells by upregulation of Sox6 and activation of JNK/MAPK/ERK pathway.","date":"2017","source":"Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas","url":"https://pubmed.ncbi.nlm.nih.gov/28225870","citation_count":21,"is_preprint":false},{"pmid":"36474273","id":"PMC_36474273","title":"PDK1- and PDK2-mediated metabolic reprogramming contributes to the TGFβ1-promoted stem-like properties in head and neck cancer.","date":"2022","source":"Cancer & 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lipoyl group-binding site inhibitor, Nov3r.","date":"2008","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18220415","citation_count":12,"is_preprint":false},{"pmid":"36016966","id":"PMC_36016966","title":"Inhibition of pyruvate dehydrogenase kinase improves carbohydrate utilization in Nile tilapia by regulating PDK2/4-PDHE1α axis and insulin sensitivity.","date":"2022","source":"Animal nutrition (Zhongguo xu mu shou yi xue hui)","url":"https://pubmed.ncbi.nlm.nih.gov/36016966","citation_count":11,"is_preprint":false},{"pmid":"33086191","id":"PMC_33086191","title":"PDK2-enhanced glycolysis promotes fibroblast proliferation in thyroid-associated ophthalmopathy.","date":"2020","source":"Journal of molecular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/33086191","citation_count":9,"is_preprint":false},{"pmid":"33817300","id":"PMC_33817300","title":"Circ_0091579 enhances the malignancy of hepatocellular carcinoma via miR-1287/PDK2 axis.","date":"2021","source":"Open 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in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/40018034","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":27817,"output_tokens":4394,"usd":0.07468,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12488,"output_tokens":4312,"usd":0.08512,"stage2_stop_reason":"end_turn"},"total_usd":0.1598,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"Wild-type p53 directly represses transcription of PDK2, thereby reducing inactive phosphorylated pyruvate dehydrogenase complex (P-PDC) and limiting conversion of pyruvate to lactate (Warburg effect). Loss of p53 allows PDK2 elevation and promotes aerobic glycolysis.\",\n      \"method\": \"p53 knockdown/overexpression in cancer cells, Western blot for PDK2 and P-PDC, lactate measurement\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — defined transcriptional mechanism with functional metabolic readout, single lab with two orthogonal methods\",\n      \"pmids\": [\"22123926\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"AZD7545, a small-molecule inhibitor of PDK2, activates PDH in vitro (EC50 ~5.2 nM in presence of PDK2) and in vivo, increasing the dephosphorylated (active) form of PDH in liver and skeletal muscle of rats and improving blood glucose control in obese Zucker rats.\",\n      \"method\": \"In vitro PDH activity assay with AZD7545 and PDK2; in vivo dosing in Wistar and obese Zucker rats; PDH activity measurement in tissue\",\n      \"journal\": \"Biochemical Society transactions\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro enzymatic inhibition assay with defined EC50, replicated in vivo in multiple animal models\",\n      \"pmids\": [\"14641018\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"PDHK2 (PDK2) knockout in mice increases PDH complex activity and lowers blood glucose in the fed state. Double knockout of PDHK2 and PDHK4 causes hypoglycaemia, ketoacidosis and hypothermia during fasting, establishing that PDK2 is the dominant regulator of PDH complex in the fed state while PDK4 dominates in the fasted state.\",\n      \"method\": \"Single and double PDK2/PDK4 knockout mice; PDH complex activity assays; blood glucose, insulin, and ketone measurements; stable isotope flux analysis\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — genetic knockout with multiple orthogonal metabolic readouts in vivo, replicated across single and double KO conditions\",\n      \"pmids\": [\"22360721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"PDK2 phosphorylates the mitochondrial rhomboid protease PARL, regulating its N-terminal autocatalytic β-cleavage. PDK2-mediated phosphorylation of PARL negatively regulates PINK1/PARKIN-mediated mitophagy by controlling production of the less-active PARL cleavage product PACT, integrating mitochondrial metabolism with mitochondrial quality control.\",\n      \"method\": \"Co-IP; phosphorylation assays; mitochondrial stress assays; PARL cleavage Western blot; mitophagy reporters\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct phosphorylation substrate identified with functional mitophagy readout, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"28178523\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"PDK2 binds the L2 lipoyl domain (E2 subunit of PDC) via a site stimulated by K+ ions at a site distinct from the ATP active site. Phosphate (Pi) is required for ADP, ATP, or pyruvate to interfere with PDK2 binding to L2 and promotes PDK2 tetramer formation. The acetyl-lipoate analog Nov3r inhibits E2-activated PDK2 (IC50 ~7.8 nM) by occupying the lipoyl-group binding site and preventing PDK2 binding to E2.\",\n      \"method\": \"Biochemical binding assays (PDHK2 and GST-L2 interaction), kinase activity assays, gel filtration for oligomeric state\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with kinetic characterization, mutagenesis/ligand competition, defined binding sites\",\n      \"pmids\": [\"18220415\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Crystal structures of PDK2 in complex with inhibitor compound 8c (at the lipoyl-binding site) and novel 4,5-diarylisoxazole derivatives GM10030/GM67520 (at the ATP-binding site) reveal remote conformational coupling between the lipoyl-binding pocket and the ATP-binding pocket, and demonstrate an unprecedented asymmetric dimer conformation of PDK2.\",\n      \"method\": \"X-ray crystallography of PDK2 co-crystal structures; isothermal titration calorimetry for binding affinity\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structures with ITC binding validation, multiple compounds confirming two binding sites\",\n      \"pmids\": [\"32444142\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PDK2 directly phosphorylates the transcription factor FOXK2 at Thr13 and Ser30 via interaction with the FOXK2 forkhead-associated (FHA) domain, enhancing FOXK2 transcriptional activity. FOXK2 in turn transcriptionally upregulates PDK2, creating a positive feedback loop that sustains glycolysis in ovarian cancer cells.\",\n      \"method\": \"Co-IP, in vitro kinase assay, site-directed mutagenesis of FOXK2 phosphorylation sites, luciferase reporter for PDK2 promoter, xenograft assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — direct substrate phosphorylation identified with mutagenesis and co-IP, positive feedback loop confirmed by reporter assay, single lab\",\n      \"pmids\": [\"38734828\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"OGT-catalyzed O-GlcNAc modification of c-Myc at Ser415 stabilizes c-Myc protein, which transcriptionally upregulates PDK2 expression. Elevated PDK2 then phosphorylates the E1α subunit of the pyruvate dehydrogenase complex (PDH), inhibiting PDH activity, reducing mitochondrial pyruvate metabolism, suppressing ROS, and promoting xenograft tumor growth.\",\n      \"method\": \"OGT depletion, c-Myc glycosylation site mutagenesis (S415A), ChIP, PDH phosphorylation assays, xenograft models\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multi-step pathway placed by genetic and biochemical methods, site-directed mutagenesis and ChIP, single lab\",\n      \"pmids\": [\"38778217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Glucocorticoid receptor (GR) directly binds the PDK2 promoter and stimulates PDK2 transcription in neurons in response to elevated glucocorticoids (GCs). Elevated PDK2 phosphorylates and inhibits PDH, reducing mitochondrial oxidative phosphorylation and TCA cycle flux. Silencing PDK2 abrogated glucocorticoid-induced PDH inhibition and restored neuronal oxidative phosphorylation.\",\n      \"method\": \"ChIP of GR at PDK2 promoter, PDK2 shRNA/siRNA knockdown, PDH phosphorylation Western blot, U-13C glucose isotope tracing, in vivo GR/PDK2 silencing with behavioral readout\",\n      \"journal\": \"Molecular psychiatry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct promoter binding by ChIP, isotope flux analysis, genetic loss-of-function, single lab\",\n      \"pmids\": [\"37188779\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PDK2 mediates alternative pre-mRNA splicing of Bnip3 in cancer cells: inhibition of PDK2 in Panc-1 cells rapidly shifts Bnip3 isoform balance from the survival truncated Bnip3Δex3 toward the pro-death full-length Bnip3FL, inducing mitochondrial perturbations and cell death, coupling the glycolytic phenotype to hypoxia resistance.\",\n      \"method\": \"PDK2 inhibition (siRNA/DCA), RT-PCR isoform analysis, mitochondrial membrane potential assay, cell death assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined molecular splicing readout, single lab with two methods\",\n      \"pmids\": [\"26416963\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PDK2 deficiency (genetic knockout and pharmacological inhibition with AZD7545) suppresses osteoclast differentiation by reducing phosphorylation of CREB and c-FOS, and consequent NFATc1 transcription downstream of RANKL signaling, thereby preventing ovariectomy-induced bone loss in mice.\",\n      \"method\": \"PDK2 knockout mice, PDK2 inhibitor AZD7545, ovariectomy model, CREB/c-FOS/NFATc1 Western blot, osteoclast differentiation assays from bone marrow cells\",\n      \"journal\": \"Journal of bone and mineral research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO and pharmacological inhibition with defined signaling pathway readout, single lab\",\n      \"pmids\": [\"33125772\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PDK2 inhibition in ischemia/reperfusion injury increases PDH activity through the PDK2-PDH-Nrf2 axis: DCA-mediated PDK2 inhibition activates PDH, promotes glycolytic flux into the TCA cycle, and elevates Nrf2 and HO-1 antioxidant proteins, reducing oxidative stress and blood-brain barrier damage.\",\n      \"method\": \"MCAO mouse model, OGD in vitro model, DCA treatment, Western blot for PDK2/PDH/Nrf2/HO-1, Nrf2-specific inhibitor ML385 rescue experiment\",\n      \"journal\": \"Oxidative medicine and cellular longevity\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological inhibition with genetic inhibitor rescue in vivo and in vitro, single lab, multiple orthogonal readouts\",\n      \"pmids\": [\"34712383\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Oroxylin A (OA) disrupts the SIRT1/PDK2/PARL axis, inhibiting mitochondrial fusion; this synergizes with GLUT1 inhibition to break mitochondrial metabolic plasticity and sensitize hepatocellular carcinoma cells to glucose restriction.\",\n      \"method\": \"Pharmacological treatment with OA, mitochondrial fusion assays, spare respiratory capacity measurement, Western blot for SIRT1/PDK2/PARL\",\n      \"journal\": \"Biomedicine & pharmacotherapy\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pathway placement inferred from pharmacological compound without direct PDK2 biochemical validation, single lab\",\n      \"pmids\": [\"37633053\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"In C. elegans, PDHK-2 (PDK2 ortholog) expression is regulated by DAF-16 and NHR-49 transcription factors and is induced during long-term starvation and dauer state. PDHK-2 deficiency preserves fat stores by reducing lipase (ATGL, HSL) expression, extending dauer survival under nutrient restriction.\",\n      \"method\": \"C. elegans genetic mutants (pdhk-2 loss-of-function alleles), fat staining, lipase gene expression, survival assays, genetic epistasis with daf-2\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — C. elegans ortholog with genetic epistasis, single lab, lipase connection indirect\",\n      \"pmids\": [\"22848591\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Chronic cigarette smoke extract (CSE) treatment upregulates PDK2 expression in oral keratinocytes, decreasing PDH activity and increasing pyruvate and lactate production. This promotes HIF1α accumulation; ROS scavengers abolish PDK2 and HIF1α induction, and PDK2 inhibition with DCA reduces HIF1α and cell proliferation.\",\n      \"method\": \"PDK2 expression by qRT-PCR/Western blot, PDH activity assay, lactate/pyruvate measurement, HIF1α Western blot, DCA and N-acetylcysteine treatment, HIF1α inhibitor\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological inhibition plus enzymatic activity assay with multiple metabolic readouts, single lab\",\n      \"pmids\": [\"21283817\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PDK2 promotes cisplatin resistance in lung adenocarcinoma via transcriptional upregulation of CNNM3. PDK2 knockdown reduces CNNM3 expression and restores cisplatin sensitivity in vitro and in vivo.\",\n      \"method\": \"PDK2 overexpression/knockdown, CNNM3 luciferase reporter, cisplatin resistance assays, xenograft models\",\n      \"journal\": \"Journal of drug targeting\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — transcriptional regulation inferred from reporter and KD, mechanism of PDK2 acting as transcriptional regulator not fully characterized, single lab\",\n      \"pmids\": [\"30457021\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PDK2 overexpression in thyroid-associated ophthalmopathy (TAO) orbital fibroblasts enhances glycolysis (increased lactate, decreased oxygen consumption) and promotes fibroblast proliferation. PDK2 knockdown reduces cytoplasmic Akt levels and proliferation in TAO cells, placing PDK2 upstream of Akt signaling in this context.\",\n      \"method\": \"PDK2 siRNA knockdown, lactate production assay, oxygen consumption assay, Akt/pAkt308 quantification by capillary Western, EdU/BrdU proliferation assays\",\n      \"journal\": \"Journal of molecular endocrinology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — KD with metabolic and proliferation readouts, Akt link is correlative, single lab\",\n      \"pmids\": [\"33086191\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PDK2 (pyruvate dehydrogenase kinase isoform 2) is a mitochondrial kinase that phosphorylates and inactivates the E1α subunit of the pyruvate dehydrogenase complex (PDC), reducing conversion of pyruvate to acetyl-CoA and promoting aerobic glycolysis; its activity is stimulated by E2-subunit lipoyl domain binding (regulated by K⁺ and Pi), inhibited by compounds occupying either the ATP-binding or lipoyl-group binding site, transcriptionally induced by p53 loss, glucocorticoid receptor, and c-Myc O-GlcNAcylation; it also phosphorylates non-PDC substrates including PARL (regulating mitophagy) and FOXK2 (sustaining a glycolytic positive feedback loop), and genetic knockout in mice establishes PDK2 as the dominant PDH complex regulator in the fed state.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PDK2 is a mitochondrial kinase that phosphorylates and inactivates the E1α subunit of the pyruvate dehydrogenase complex (PDC), throttling conversion of pyruvate to acetyl-CoA and shifting cells toward aerobic glycolysis [#7]. Genetic knockout studies establish PDK2 as the dominant regulator of PDC activity in the fed state, with loss raising PDC activity and lowering blood glucose, while combined PDK2/PDK4 deletion produces fasting hypoglycaemia and ketoacidosis [#2]. Its kinase activity is allosterically governed by binding to the L2 lipoyl domain of the PDC E2 subunit, a site stimulated by K+ ions and dependent on inorganic phosphate, which also promotes PDK2 tetramerization and renders the enzyme sensitive to lipoyl-site occupancy; pharmacological and structural work defines two distinct druggable pockets—an ATP-binding active site (AZD7545, diarylisoxazoles) and a lipoyl-group binding site (Nov3r, compound 8c)—that are conformationally coupled across an asymmetric PDK2 dimer [#1, #4, #5]. PDK2 expression is transcriptionally elevated by loss of wild-type p53, by glucocorticoid receptor binding to the PDK2 promoter, and by O-GlcNAc-stabilized c-Myc, in each case suppressing PDH-driven oxidative metabolism in cancer cells and neurons [#0, #7, #8]. Beyond the PDC, PDK2 phosphorylates the mitochondrial rhomboid protease PARL to restrain PINK1/PARKIN-dependent mitophagy [#3] and phosphorylates the transcription factor FOXK2 at Thr13/Ser30 via its FHA domain, establishing a FOXK2–PDK2 positive feedback loop that sustains glycolysis [#6]. Through these activities PDK2 couples mitochondrial pyruvate flux to redox balance and pathological phenotypes, including tumor growth, ischemia/reperfusion injury via a PDK2-PDH-Nrf2 antioxidant axis, and RANKL-driven osteoclast differentiation and bone loss [#10, #11].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"Established PDK2 as a tractable pharmacological target whose inhibition reactivates PDH and improves systemic glucose handling, defining the enzyme's metabolic switch role in vivo.\",\n      \"evidence\": \"In vitro PDH activity assay with the inhibitor AZD7545 (EC50 ~5.2 nM) and in vivo dosing in Wistar and obese Zucker rats\",\n      \"pmids\": [\"14641018\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not resolve isoform selectivity of AZD7545 across PDK1-4\", \"No structural basis for inhibition provided at this stage\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defined the allosteric architecture of PDK2 regulation by showing lipoyl-domain (L2/E2) binding, K+ and phosphate dependence, and a distinct lipoyl-group inhibitory pocket separate from the ATP site.\",\n      \"evidence\": \"Biochemical binding assays of PDHK2 with GST-L2, kinase activity assays, gel filtration for oligomeric state, ligand competition with Nov3r (IC50 ~7.8 nM)\",\n      \"pmids\": [\"18220415\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic structure of the two binding sites not yet resolved here\", \"Physiological trigger for tetramer formation in vivo unclear\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Connected PDK2 to tumor metabolism by identifying wild-type p53 as a direct transcriptional repressor whose loss elevates PDK2 and drives the Warburg effect.\",\n      \"evidence\": \"p53 knockdown/overexpression in cancer cells, Western blot for PDK2 and phospho-PDC, lactate measurement\",\n      \"pmids\": [\"22123926\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct p53 binding element on PDK2 promoter not mapped\", \"Single-lab transcriptional mechanism\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Placed PDK2 in a redox-responsive feed-forward loop with HIF1α, showing carcinogen-induced ROS upregulates PDK2 to sustain glycolysis and HIF1α accumulation.\",\n      \"evidence\": \"PDK2 qRT-PCR/Western blot, PDH activity and lactate/pyruvate assays, HIF1α blots, DCA and N-acetylcysteine treatment in oral keratinocytes\",\n      \"pmids\": [\"21283817\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ROS acts on PDK2 transcription directly or via an intermediate is unresolved\", \"Single cell-type context\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Genetic knockout established PDK2 as the dominant physiological regulator of PDC in the fed state, distinguishing its role from PDK4's fasting dominance.\",\n      \"evidence\": \"Single and double PDK2/PDK4 knockout mice; PDC activity assays; blood glucose, insulin, ketone, and stable-isotope flux measurements\",\n      \"pmids\": [\"22360721\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Tissue-specific contributions not dissected\", \"Does not address non-PDC substrate functions in vivo\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Extended PDK2 substrate scope beyond the PDC by identifying PARL phosphorylation as a link between mitochondrial metabolism and mitophagy.\",\n      \"evidence\": \"Co-IP, phosphorylation assays, PARL cleavage Western blot, mitophagy reporters under mitochondrial stress\",\n      \"pmids\": [\"28178523\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Phosphosite on PARL not pinpointed\", \"Single-lab finding without reciprocal validation\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Implicated PDK2 in coupling glycolytic phenotype to hypoxia/apoptosis resistance through Bnip3 alternative splicing.\",\n      \"evidence\": \"PDK2 inhibition (siRNA/DCA), RT-PCR isoform analysis, mitochondrial membrane potential and cell-death assays in Panc-1 cells\",\n      \"pmids\": [\"26416963\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking a mitochondrial kinase to nuclear splicing not defined\", \"No direct splicing-factor target identified\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Provided structural proof of two coupled drug-binding pockets and an asymmetric PDK2 dimer, rationalizing allosteric inhibition.\",\n      \"evidence\": \"X-ray co-crystal structures with compound 8c (lipoyl site) and diarylisoxazoles GM10030/GM67520 (ATP site); ITC binding validation\",\n      \"pmids\": [\"32444142\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Conformational coupling shown structurally but not kinetically dissected\", \"Dimer asymmetry functional consequence in vivo unknown\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked PDK2 activity to RANKL-driven osteoclastogenesis and bone homeostasis, broadening its physiological role beyond glucose metabolism.\",\n      \"evidence\": \"PDK2 knockout mice and AZD7545 inhibition, ovariectomy model, CREB/c-FOS/NFATc1 blots, osteoclast differentiation assays\",\n      \"pmids\": [\"33125772\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How PDH/metabolic flux feeds into CREB/c-FOS signaling not mechanistically resolved\", \"Single-lab study\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined a PDK2-PDH-Nrf2 antioxidant axis governing oxidative stress and blood-brain barrier integrity in ischemia/reperfusion.\",\n      \"evidence\": \"MCAO and OGD models, DCA inhibition, Nrf2/HO-1 blots, ML385 Nrf2-inhibitor rescue\",\n      \"pmids\": [\"34712383\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Reliance on pharmacological DCA rather than genetic PDK2 loss\", \"Direct vs metabolic-flux-mediated Nrf2 induction not separated\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified glucocorticoid receptor as a direct transcriptional driver of PDK2 in neurons, suppressing oxidative phosphorylation in response to glucocorticoids.\",\n      \"evidence\": \"ChIP of GR at PDK2 promoter, PDK2 knockdown, PDH phosphorylation blots, U-13C glucose tracing, in vivo silencing with behavioral readout\",\n      \"pmids\": [\"37188779\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GR binding element sequence not defined\", \"Single-lab neuronal context\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Revealed a c-Myc–PDK2 transcriptional input controlled by O-GlcNAcylation, linking nutrient-sensing post-translational modification to PDH suppression and tumor growth.\",\n      \"evidence\": \"OGT depletion, c-Myc S415A glycosylation-site mutagenesis, ChIP, PDH phosphorylation assays, xenograft models\",\n      \"pmids\": [\"38778217\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct c-Myc occupancy element on PDK2 promoter not mapped beyond ChIP\", \"Single-lab pathway\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified FOXK2 as a direct PDK2 phosphorylation substrate forming a glycolytic positive feedback loop, the first transcription-factor substrate establishing reciprocal PDK2 regulation.\",\n      \"evidence\": \"Co-IP, in vitro kinase assay, FOXK2 Thr13/Ser30 mutagenesis, PDK2 promoter luciferase reporter, xenograft assay in ovarian cancer\",\n      \"pmids\": [\"38734828\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of FHA-domain recognition not solved\", \"Loop dynamics in non-cancer cells untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How PDK2's distinct activities—PDC inactivation versus non-canonical substrate phosphorylation (PARL, FOXK2) and reported transcriptional/proliferative effects—are coordinated, and which are druggable independently, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model reconciling mitochondrial kinase activity with apparent transcriptional/splicing influence\", \"Substrate phosphosite specificity determinants undefined\", \"Isoform-selective therapeutic exploitation not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [3, 6, 7]},\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [1, 4, 7]},\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [3, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [1, 2, 7]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"PDHA1\", \"PARL\", \"FOXK2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}