{"gene":"IP6K1","run_date":"2026-06-10T01:55:23","timeline":{"discoveries":[{"year":2016,"finding":"IP6K1 catalytic activity is required for cytoplasmic dynein-driven vesicle transport; IP7 pyrophosphorylates Ser51 in the dynein intermediate chain (IC), promoting IC interaction with the p150(Glued) subunit of dynactin, and cells lacking IP6K1 show decreased IC-p150(Glued) interaction and reduced IC recruitment to membranes.","method":"KO cells with rescue by active/inactive IP6K1, in vitro pyrophosphorylation assay, Co-IP, endosomal transport assays","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro pyrophosphorylation assay identifying specific substrate residue, active vs. inactive rescue, Co-IP, multiple orthogonal methods in single study","pmids":["27474409"],"is_preprint":false},{"year":2016,"finding":"IP6K1 catalytic activity (5-IP7 synthesis) promotes cell migration and invasion via regulation of actin cytoskeleton dynamics and adhesion-dependent FAK/Paxillin signaling; expression of active but not inactive IP6K1 rescues migration defects in IP6K1 KO MEFs.","method":"KO MEFs with active/inactive IP6K1 rescue, gene expression analysis, immunoblot for FAK/Paxillin activation, migration/invasion assays","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — active vs. inactive rescue with specific signaling readouts, single lab, multiple methods","pmids":["27140681"],"is_preprint":false},{"year":2016,"finding":"IP6K1 inhibits AMPK-mediated thermogenesis in adipocytes; adipocyte-specific Ip6k1 deletion enhances AMPK activation and thermogenic energy expenditure, and IP6 and IP6K1 differentially regulate upstream kinase-mediated AMPK stimulatory phosphorylation in vitro.","method":"Adipocyte-specific KO mice, in vitro AMPK phosphorylation assay, AMPK depletion rescue, thermogenesis/EE measurements, UCP1/PGC1α expression analysis","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro mechanistic assay plus conditional KO with AMPK depletion rescue, replicated across multiple temperature conditions and cell types","pmids":["27701146"],"is_preprint":false},{"year":2016,"finding":"IP6K1 preferentially binds the phospholipid phosphatidic acid (PA), and this PA binding is required for IP6K1 nuclear localization and negative regulation of myo-inositol-3-P synthase (MIPS/Isyna1) transcription, thereby suppressing inositol synthesis.","method":"Ip6k1 ablation, lipid-binding assay, subcellular fractionation/nuclear localization imaging, gene expression analysis of Isyna1","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — direct lipid-binding assay plus localization and transcriptional readout, single lab","pmids":["26953345"],"is_preprint":false},{"year":2022,"finding":"Plasma membrane-derived phosphatidic acid (PA), synthesized via the AMPK-PLD pathway, induces nuclear translocation of IP6K1 and represses MIPS protein expression; endoplasmic reticulum-derived PA does not induce IP6K1 translocation.","method":"Pharmacological PLD stimulation, direct PA supplementation, AMPK activation by glucose deprivation/valproate/lithium, subcellular localization imaging, MIPS immunoblot","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — multiple pharmacological tools with specific localization and protein-level readouts, single lab","pmids":["35963434"],"is_preprint":false},{"year":2017,"finding":"IP6K1 is a component of the chromatoid body in round spermatids; its deletion leads to absence of chromatoid bodies, premature translational derepression of TNP2 and PRM2, and azoospermia in male mice.","method":"Ip6k1 KO mice, immunofluorescence localization, expression analysis of chromatoid body markers and spermatid-specific proteins","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization in spermatids combined with specific KO phenotype readouts, single lab","pmids":["28743739"],"is_preprint":false},{"year":2019,"finding":"IP6K1 and IP6K2 together control synthesis of IP7 and IP8 in human cells and regulate phosphate homeostasis; inositol pyrophosphates bind to the SPX domain of the phosphate exporter XPR1 and regulate its activity, controlling both phosphate import and export.","method":"IP6K1/2 double KO in HCT116 cells, PAGE and HPLC analysis of inositol polyphosphates, nucleotide analysis, Malachite green assay, [32Pi] pulse labeling, SPX domain binding assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal biochemical methods (HPLC, radiolabeling, direct binding assay), genetic KO with functional rescue, single lab but rigorous","pmids":["31186349"],"is_preprint":false},{"year":2018,"finding":"IP6K1 in platelets mediates inorganic polyphosphate (polyP) production; platelet-derived polyP is essential for neutrophil-platelet aggregate (NPA) formation and neutrophil accumulation in alveolar spaces during bacterial pneumonia, acting through the bradykinin pathway.","method":"Ip6k1 KO mice, platelet depletion, polyP rescue experiments, IP6K1 inhibitor TNP, serum polyP measurement, NPA quantification","journal":"Science translational medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO, pharmacological inhibition, and polyP rescue in multiple bacterial infection models with specific mechanistic readouts","pmids":["29618559"],"is_preprint":false},{"year":2021,"finding":"IP6K1 acts independently of its catalytic activity to upregulate P-body formation by binding to ribosomes and interacting with the mRNA decapping complex (EDC4, DCP1A/B, DCP2, DDX6), augmenting the DDX6-4E-T interaction on the 5' mRNA cap and promoting translational repression over initiation.","method":"IP6K1 KD/KO cells, active vs. inactive IP6K1 rescue, Co-IP of IP6K1 with ribosome and decapping complex components, P-body formation assays, miRNA-mediated suppression assays, DCP2-regulated transcript stability","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — Co-IP with multiple components, catalytic-dead rescue, functional readouts, single lab","pmids":["34841428"],"is_preprint":false},{"year":2021,"finding":"IP6K1 interacts with the enzyme O-GlcNAcase in the liver; IP6K1 deletion reduces protein O-GlcNAcylation in mouse livers and in hepatocyte-specific KO mice.","method":"Co-immunoprecipitation, mass spectrometry, immunoblotting for O-GlcNAcylation in KO livers","journal":"Molecular metabolism","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP plus expression readout, single lab, limited mechanistic follow-up in abstract","pmids":["34757046"],"is_preprint":false},{"year":2024,"finding":"IP6K1 binds to apoA-I and, via its product 5PP-InsP5, induces apoA-I degradation requiring ubiquitination factor E4A (UBE4A); depleting 5PP-InsP5 by IP6K1 deletion disrupts UBE4A-apoA-I interaction, preventing apoA-I degradation and increasing circulating apoA-I levels.","method":"Co-immunoprecipitation, chemical biology tools for 5PP-InsP5 binding, hepatocyte-specific IP6K1 KO mice, IP6K1/apoA-I double KO validation","journal":"Metabolism: clinical and experimental","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifying binding partners, chemical biology for pyrophosphate-protein interaction, genetic validation in vivo, single lab","pmids":["39643078"],"is_preprint":false},{"year":2024,"finding":"IP6K1 interacts with substrate proteins targeted for 5-InsP7-mediated pyrophosphorylation (including NOLC1, TCOF, UBF1, AP3B1) and with CK2 kinase; a trimeric complex of IP6K1-AP3B1-CK2α was demonstrated, and disrupting IP6K1 binding to AP3B1 lowers AP3B1 pyrophosphorylation in vivo, supporting coordinated pre-phosphorylation and pyrophosphorylation.","method":"Mass spectrometry interactome, Co-IP of trimeric complex, disruption of IP6K1-AP3B1 binding with in vivo pyrophosphorylation readout","journal":"Bioscience reports","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — MS interactome plus Co-IP of trimeric complex plus functional disruption assay, single lab","pmids":["39230924"],"is_preprint":false},{"year":2024,"finding":"IP6K1-generated 5-InsP7 governs the degradation of Na+/K+-ATPase (NKA) via the autoinhibitory domain of PI3K p85α; IP6K1 KO neurons show enriched NKA, lower action potential frequency, and deeper afterhyperpolarization, demonstrating that IP6K1 regulates neuronal excitability through NKA stability.","method":"IP6K1 KO mouse neurons, whole-cell electrophysiology, action potential recording","journal":"Molecular brain","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct electrophysiological readout in KO neurons consistent with proposed NKA mechanism, single lab, mechanism cited from prior work","pmids":["38350944"],"is_preprint":false},{"year":2025,"finding":"IP6K1 mediates hyperglycemia-induced endothelial senescence by stabilizing LKB1 (by disrupting Hsp/Hsc70 and CHIP-mediated LKB1 degradation) and switching LKB1 signaling from AMPK activation to p53 pathway activation; endothelial-specific IP6K1 deletion attenuates this senescence.","method":"Endothelial-specific IP6K1 KO and OE mice, Co-IP of LKB1 with Hsp70/CHIP and p53, phosphorylation assays for AMPK vs. p53 targets","journal":"Diabetes","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-type-specific KO/OE with mechanistic Co-IP, pathway switching assay, single lab","pmids":["39792359"],"is_preprint":false},{"year":2024,"finding":"IP6K1 and IP6K2 are required for normal expression and function of the renal Na+/Pi cotransporters NaPi-IIa and NaPi-IIc; renal tubular-specific double KO mice show downregulation of NaPi-IIa/IIc, reduced proximal tubule phosphate uptake, and hypophosphatemia.","method":"Renal tubular-specific Ip6k1/2 double KO mice, in vitro opossum kidney cells with depletion, mRNA/protein expression assays, brush border membrane phosphate uptake assay","journal":"Journal of the American Society of Nephrology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — tissue-specific KO with functional transport assay and expression readouts, two model systems, but IP6K1 and IP6K2 studied together, not individually","pmids":["38317282"],"is_preprint":false},{"year":2019,"finding":"IP6K1 platelet activity regulates NET-microparticle complex formation in acute pancreatitis; IP6K1-deficient platelets fail to support thrombin-induced NET formation when mixed with wild-type neutrophils, and polyphosphate rescue restores NET formation.","method":"IP6K1 KO mice, platelet-neutrophil mixing experiments, polyphosphate rescue, electron microscopy, STAT-3 phosphorylation assay","journal":"JCI insight","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with polyphosphate rescue, mechanistic dissection of platelet-neutrophil interaction, single lab","pmids":["31593553"],"is_preprint":false},{"year":2026,"finding":"IP6K1 interacts with the proteoglycan syndecan-4 (SDC4) to support secretory granule biogenesis in gastric chief cells; this function is independent of IP6K1 catalytic activity, as both active and inactive IP6K1 rescue pepsinogen C (PGC) granule formation in IP6K1 KO AGS cells.","method":"Ip6k1 KO mice, CRISPR KO in AGS cells, active/inactive IP6K1 rescue, Co-IP/interactome for SDC4, colocalization of SDC4 with PGC granules","journal":"American journal of physiology. Gastrointestinal and liver physiology","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — catalytic-dead rescue establishing activity-independence, Co-IP of SDC4, CRISPR model plus mouse model, single lab","pmids":["42053465"],"is_preprint":false},{"year":2025,"finding":"IP6K1-generated 5-InsP7 regulates mitochondrial polyphosphate (polyP) levels; IP6K1 KO cells and mice show reduced mitochondrial polyP, impaired mitochondrial respiration and membrane potential; expression of catalytically active but not inactive IP6K1 restores mitochondrial polyP and membrane potential, while both active and inactive forms rescue mitochondrial respiration.","method":"IP6K1 KO cells and mice, DAPI fluorescence-based polyP quantification, mitochondrial fractionation, active/inactive IP6K1 rescue, mitochondrial respiration and membrane potential assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — active vs. inactive rescue dissecting catalytic from non-catalytic functions, quantitative polyP assay in fractionated compartments, preprint not yet peer-reviewed","pmids":["bio_10.1101_2025.06.17.659843"],"is_preprint":true},{"year":2025,"finding":"IP6K1 is a substrate of the Cys-Arg/N-degron pathway under hypoxia; loss of IP6K1 impairs glucose uptake, glycolytic ATP production, and mitochondrial morphology and function, disrupting metabolic adaptation under hypoxic conditions.","method":"Systematic proteomics/N-degron pathway screen, IP6K1 KO cells under hypoxia, glucose uptake and metabolic flux assays","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — proteomics screen identifying IP6K1 as substrate, KO phenotype, single lab, preprint, limited mechanistic detail for IP6K1 specifically","pmids":["bio_10.1101_2025.01.20.633921"],"is_preprint":true},{"year":2010,"finding":"Recombinant mouse IP6K1 purified from E. coli synthesizes InsP7 (5-IP7) from IP6 in vitro, and this purified enzyme can pyrophosphorylate protein substrates from different species, establishing IP6K1's enzymatic activity and its product as a protein-modifying agent.","method":"Recombinant protein purification from E. coli, in vitro kinase assay with cold and [32P]-labeled substrates, protein pyrophosphorylation assay","journal":"Methods in molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in vitro reconstitution of enzymatic activity with purified recombinant protein and radiolabeled substrate","pmids":["20645182"],"is_preprint":false}],"current_model":"IP6K1 is an inositol hexakisphosphate kinase that converts IP6 to the inositol pyrophosphate 5-IP7, which regulates diverse cellular processes including dynein-driven vesicle transport (via pyrophosphorylation of dynein IC Ser51), AMPK-mediated thermogenesis and energy metabolism, cellular phosphate homeostasis (through XPR1 SPX domain binding and renal NaPi cotransporter regulation), P-body formation, inositol synthesis (via PA-dependent nuclear translocation and MIPS repression), apoA-I stability (via UBE4A), LKB1-p53 endothelial senescence signaling, mitochondrial polyphosphate production, and secretory granule biogenesis—with some functions (P-body formation, secretory granule biogenesis) shown to be independent of its catalytic activity."},"narrative":{"mechanistic_narrative":"IP6K1 is an inositol hexakisphosphate kinase that synthesizes the inositol pyrophosphate 5-IP7 (5-InsP7) from IP6, and the enzyme's product serves as a protein-modifying agent capable of pyrophosphorylating protein substrates in vitro [PMID:20645182]. Through 5-IP7-mediated pyrophosphorylation, IP6K1 controls intracellular trafficking — pyrophosphorylating Ser51 of the dynein intermediate chain to promote its interaction with the dynactin p150(Glued) subunit and drive vesicle transport [PMID:27474409] — and it physically organizes substrate pyrophosphorylation by assembling with the priming kinase CK2 and target proteins such as AP3B1 into a coordinated pre-phosphorylation/pyrophosphorylation complex [PMID:39230924]. A major theme is metabolic and phosphate regulation: IP6K1 (together with IP6K2) governs cellular inositol pyrophosphate pools that bind the SPX domain of the phosphate exporter XPR1 to set phosphate homeostasis [PMID:31186349] and is required for renal Na+/Pi cotransporter expression and proximal tubule phosphate uptake [PMID:38317282]. In adipocytes IP6K1 restrains AMPK-mediated thermogenesis and energy expenditure [PMID:27701146], and its catalytic activity supports mitochondrial polyphosphate production, respiration, and membrane potential [PMID:bio_10.1101_2025.06.17.659843]. IP6K1 also acts non-catalytically: it binds ribosomes and the mRNA decapping complex to promote P-body formation and translational repression [PMID:34841428], and interacts with syndecan-4 to support secretory granule biogenesis, with both active and inactive enzyme rescuing these functions [PMID:42053465]. Additional 5-IP7-dependent roles include UBE4A-mediated apoA-I degradation [PMID:39643078], LKB1 stabilization that switches signaling toward p53 in hyperglycemia-induced endothelial senescence [PMID:39792359], and regulation of neuronal Na+/K+-ATPase stability and excitability [PMID:38350944]. IP6K1 is essential for chromatoid body assembly and spermatogenesis [PMID:28743739] and for platelet polyphosphate production driving neutrophil-platelet aggregates and NET formation in infection and inflammation [PMID:29618559, PMID:31593553].","teleology":[{"year":2010,"claim":"Established the foundational biochemistry: that IP6K1 is an enzyme generating 5-IP7 and that this product can covalently modify proteins by pyrophosphorylation.","evidence":"Recombinant mouse IP6K1 from E. coli with in vitro kinase and protein pyrophosphorylation assays using radiolabeled substrates","pmids":["20645182"],"confidence":"High","gaps":["Did not identify physiological protein substrates","No cellular phenotype linked to enzymatic output"]},{"year":2016,"claim":"Connected IP6K1 catalytic output to specific cellular machinery by identifying a defined pyrophosphorylation substrate residue controlling motor-adaptor coupling and vesicle transport.","evidence":"KO cells with active/inactive rescue, in vitro pyrophosphorylation of dynein IC Ser51, Co-IP and endosomal transport assays","pmids":["27474409"],"confidence":"High","gaps":["Stoichiometry and reversibility of Ser51 pyrophosphorylation in vivo not defined","Other dynein-cargo specificities not addressed"]},{"year":2016,"claim":"Defined IP6K1 as a metabolic brake on thermogenesis, showing its catalytic activity opposes AMPK activation and energy expenditure in adipose tissue.","evidence":"Adipocyte-specific KO mice, in vitro AMPK phosphorylation assay with AMPK depletion rescue, thermogenesis measurements","pmids":["27701146"],"confidence":"High","gaps":["Direct molecular link between 5-IP7 and the upstream AMPK kinase not fully resolved","Tissue-autonomous vs systemic contributions not separated"]},{"year":2016,"claim":"Revealed a lipid-sensing input to IP6K1 localization: PA binding drives nuclear translocation to repress inositol synthesis, creating a feedback loop on substrate availability.","evidence":"Ip6k1 ablation, lipid-binding assay, nuclear localization imaging, Isyna1/MIPS transcriptional readout; later extended with PLD/AMPK pharmacology","pmids":["26953345","35963434"],"confidence":"Medium","gaps":["Direct PA-IP6K1 binding interface not mapped","Mechanism of MIPS transcriptional/protein-level repression by nuclear IP6K1 unresolved"]},{"year":2016,"claim":"Linked IP6K1 catalytic activity to cytoskeletal dynamics and adhesion signaling underlying cell migration.","evidence":"KO MEFs with active/inactive rescue, FAK/Paxillin immunoblot, migration and invasion assays","pmids":["27140681"],"confidence":"Medium","gaps":["No direct 5-IP7 substrate in the FAK/Paxillin axis identified","Single cell-type model"]},{"year":2017,"claim":"Demonstrated an essential developmental role in male germ cells via chromatoid body assembly and translational control.","evidence":"Ip6k1 KO mice, immunofluorescence of chromatoid body markers, TNP2/PRM2 expression analysis","pmids":["28743739"],"confidence":"Medium","gaps":["Whether the chromatoid body role is catalytic or structural not dissected","Molecular partners in the chromatoid body unidentified"]},{"year":2018,"claim":"Established IP6K1 as a producer of platelet inorganic polyphosphate driving innate immune aggregate formation in infection.","evidence":"Ip6k1 KO mice, platelet depletion, polyP rescue, IP6K1 inhibitor TNP, NPA quantification in bacterial pneumonia","pmids":["29618559"],"confidence":"High","gaps":["Enzymatic mechanism linking 5-IP7 to polyP synthesis not defined","Bradykinin pathway connection mechanistically incomplete"]},{"year":2019,"claim":"Extended the platelet polyP role to NET-microparticle complex formation, showing IP6K1-dependent platelet support of neutrophil function.","evidence":"IP6K1 KO mice, platelet-neutrophil mixing, polyP rescue, electron microscopy, STAT-3 phosphorylation","pmids":["31593553"],"confidence":"Medium","gaps":["Direct molecular effector of polyP on NET formation unresolved","Single disease model (pancreatitis)"]},{"year":2019,"claim":"Placed IP6K1 at the center of cellular phosphate homeostasis by linking its inositol pyrophosphate products to SPX-domain regulation of the XPR1 phosphate exporter.","evidence":"IP6K1/2 double KO in HCT116, HPLC and radiolabeling of inositol pyrophosphates, SPX domain binding assay","pmids":["31186349"],"confidence":"High","gaps":["Individual IP6K1 vs IP6K2 contribution not separated","Whether IP6K1 directly contacts XPR1 vs acts through diffusible 5-IP7 unresolved"]},{"year":2021,"claim":"Uncovered a catalysis-independent function: IP6K1 scaffolds ribosomes and the decapping complex to promote P-body formation and translational repression.","evidence":"KD/KO cells, active/inactive rescue, Co-IP with ribosome and EDC4/DCP1A-B/DCP2/DDX6, P-body and miRNA suppression assays","pmids":["34841428"],"confidence":"Medium","gaps":["Direct binding interface within the decapping complex not mapped","How a catalytic kinase performs a structural scaffolding role unexplained"]},{"year":2021,"claim":"Identified a hepatic interaction with O-GlcNAcase linking IP6K1 to protein O-GlcNAcylation.","evidence":"Co-IP, mass spectrometry, O-GlcNAcylation immunoblot in KO livers","pmids":["34757046"],"confidence":"Low","gaps":["Single Co-IP plus expression readout without reciprocal validation","Mechanism by which IP6K1 affects O-GlcNAcase activity unknown"]},{"year":2024,"claim":"Showed how IP6K1 organizes substrate pyrophosphorylation by forming a CK2-IP6K1-substrate complex coupling priming phosphorylation to pyrophosphorylation.","evidence":"MS interactome, Co-IP of IP6K1-AP3B1-CK2alpha trimer, disruption of IP6K1-AP3B1 binding with in vivo pyrophosphorylation readout","pmids":["39230924"],"confidence":"Medium","gaps":["Generality of the trimeric complex across substrates not established","Structural basis of substrate selection unresolved"]},{"year":2024,"claim":"Defined a 5PP-InsP5/UBE4A-dependent pathway controlling apoA-I degradation and circulating lipoprotein levels.","evidence":"Co-IP, chemical biology tools for 5PP-InsP5 binding, hepatocyte-specific KO and IP6K1/apoA-I double KO mice","pmids":["39643078"],"confidence":"Medium","gaps":["Whether apoA-I pyrophosphorylation directly triggers UBE4A recruitment not shown","Ubiquitination steps downstream of UBE4A undefined"]},{"year":2024,"claim":"Established a renal physiological role in phosphate reabsorption via control of NaPi cotransporter expression.","evidence":"Renal tubular-specific Ip6k1/2 double KO mice and opossum kidney cells, expression assays, brush border phosphate uptake","pmids":["38317282"],"confidence":"Medium","gaps":["IP6K1 and IP6K2 studied jointly, not individually","Mechanism linking inositol pyrophosphates to NaPi-IIa/IIc expression unresolved"]},{"year":2024,"claim":"Linked IP6K1 catalytic output to neuronal excitability through 5-InsP7-governed Na+/K+-ATPase stability.","evidence":"IP6K1 KO mouse neurons, whole-cell electrophysiology and action potential recording","pmids":["38350944"],"confidence":"Medium","gaps":["The PI3K p85alpha autoinhibitory mechanism cited from prior work, not directly demonstrated here","Direct NKA pyrophosphorylation in neurons not shown"]},{"year":2025,"claim":"Revealed a pathological signaling switch in which IP6K1 stabilizes LKB1 and redirects its output from AMPK toward p53 to drive endothelial senescence in hyperglycemia.","evidence":"Endothelial-specific KO/OE mice, Co-IP of LKB1 with Hsp70/CHIP and p53, AMPK vs p53 phosphorylation assays","pmids":["39792359"],"confidence":"Medium","gaps":["Whether LKB1 stabilization requires direct pyrophosphorylation not established","Molecular determinant of the AMPK-to-p53 switch unresolved"]},{"year":2025,"claim":"Connected IP6K1 catalytic activity to mitochondrial polyphosphate, respiration, and membrane potential, while separating catalytic from non-catalytic contributions to mitochondrial function.","evidence":"IP6K1 KO cells and mice, DAPI polyP quantification in mitochondrial fractions, active/inactive rescue, respiration and membrane potential assays (preprint)","pmids":["bio_10.1101_2025.06.17.659843"],"confidence":"Medium","gaps":["Preprint not yet peer-reviewed","Mechanism by which 5-InsP7 promotes mitochondrial polyP synthesis undefined"]},{"year":2025,"claim":"Identified IP6K1 itself as a regulated substrate of the Cys-Arg/N-degron pathway under hypoxia, linking its stability to metabolic adaptation.","evidence":"Proteomics/N-degron screen, IP6K1 KO cells under hypoxia, glucose uptake and metabolic flux assays (preprint)","pmids":["bio_10.1101_2025.01.20.633921"],"confidence":"Low","gaps":["Preprint with limited IP6K1-specific mechanistic detail","Degron sequence and E3 ligase for IP6K1 not defined"]},{"year":2026,"claim":"Established a further catalysis-independent role in secretory granule biogenesis through interaction with syndecan-4.","evidence":"Ip6k1 KO mice, CRISPR KO AGS cells, active/inactive rescue, Co-IP/interactome for SDC4, colocalization with PGC granules","pmids":["42053465"],"confidence":"Medium","gaps":["Structural basis of IP6K1-SDC4 interaction unmapped","How the interaction promotes granule biogenesis mechanistically unresolved"]},{"year":null,"claim":"How IP6K1's catalytic (5-IP7 pyrophosphorylation) and non-catalytic (scaffolding) functions are partitioned and coordinated across its many cellular roles remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying structural model distinguishing catalytic vs scaffold modes","Tissue-specific substrate repertoire of 5-IP7 incompletely defined","Regulation of IP6K1 subcellular localization and stability across contexts incomplete"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[19,0,6]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,11,19]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[3,4]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[8]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[3,4]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[8,0]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[17]}],"pathway":[{"term_id":"R-HSA-382551","term_label":"Transport of small molecules","supporting_discovery_ids":[6,14]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[2,17]},{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[8]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,16]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[7,15]}],"complexes":["IP6K1-AP3B1-CK2alpha complex","mRNA decapping complex (EDC4/DCP1A-B/DCP2/DDX6)","chromatoid body"],"partners":["AP3B1","CK2ALPHA","DDX6","EDC4","UBE4A","LKB1","SDC4","XPR1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q92551","full_name":"Inositol hexakisphosphate kinase 1","aliases":["Inositol hexaphosphate kinase 1"],"length_aa":441,"mass_kda":50.2,"function":"Converts inositol hexakisphosphate (InsP6) to diphosphoinositol pentakisphosphate (InsP7/PP-InsP5). Converts 1,3,4,5,6-pentakisphosphate (InsP5) to PP-InsP4","subcellular_location":"Cytoplasm; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q92551/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/IP6K1","classification":"Not Classified","n_dependent_lines":4,"n_total_lines":1208,"dependency_fraction":0.0033112582781456954},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"SEC61B","stoichiometry":0.2},{"gene":"VCP","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/IP6K1","total_profiled":1310},"omim":[{"mim_id":"621025","title":"RAB3A-INTERACTING PROTEIN-LIKE 1; RAB3IL1","url":"https://www.omim.org/entry/621025"},{"mim_id":"606992","title":"INOSITOL HEXAPHOSPHATE KINASE 2; IP6K2","url":"https://www.omim.org/entry/606992"},{"mim_id":"606991","title":"INOSITOL HEXAPHOSPHATE KINASE 1; IP6K1","url":"https://www.omim.org/entry/606991"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoli fibrillar center","reliability":"Supported"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/IP6K1"},"hgnc":{"alias_symbol":["KIAA0263"],"prev_symbol":["IHPK1"]},"alphafold":{"accession":"Q92551","domains":[{"cath_id":"3.30.470.160","chopping":"23-98_159-344_389-438","consensus_level":"medium","plddt":89.3963,"start":23,"end":438}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92551","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q92551-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q92551-F1-predicted_aligned_error_v6.png","plddt_mean":74.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=IP6K1","jax_strain_url":"https://www.jax.org/strain/search?query=IP6K1"},"sequence":{"accession":"Q92551","fasta_url":"https://rest.uniprot.org/uniprotkb/Q92551.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q92551/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92551"}},"corpus_meta":[{"pmid":"31186349","id":"PMC_31186349","title":"The inositol hexakisphosphate kinases IP6K1 and -2 regulate human cellular phosphate homeostasis, including XPR1-mediated phosphate export.","date":"2019","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31186349","citation_count":87,"is_preprint":false},{"pmid":"27701146","id":"PMC_27701146","title":"Adipocyte-specific deletion of Ip6k1 reduces diet-induced obesity by enhancing AMPK-mediated thermogenesis.","date":"2016","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/27701146","citation_count":73,"is_preprint":false},{"pmid":"27474409","id":"PMC_27474409","title":"Inositol hexakisphosphate kinase 1 (IP6K1) activity is required for cytoplasmic dynein-driven transport.","date":"2016","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/27474409","citation_count":59,"is_preprint":false},{"pmid":"27140681","id":"PMC_27140681","title":"Deletion of inositol hexakisphosphate kinase 1 (IP6K1) reduces cell migration and invasion, conferring protection from aerodigestive tract carcinoma in mice.","date":"2016","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/27140681","citation_count":51,"is_preprint":false},{"pmid":"27689003","id":"PMC_27689003","title":"TNP [N2-(m-Trifluorobenzyl), N6-(p-nitrobenzyl)purine] ameliorates diet induced obesity and insulin resistance via inhibition of the IP6K1 pathway.","date":"2016","source":"Molecular metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/27689003","citation_count":47,"is_preprint":false},{"pmid":"29618559","id":"PMC_29618559","title":"Inhibition of IP6K1 suppresses neutrophil-mediated pulmonary damage in bacterial pneumonia.","date":"2018","source":"Science translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/29618559","citation_count":43,"is_preprint":false},{"pmid":"28123939","id":"PMC_28123939","title":"Global IP6K1 deletion enhances temperature modulated energy expenditure which reduces carbohydrate and fat induced weight gain.","date":"2016","source":"Molecular metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/28123939","citation_count":37,"is_preprint":false},{"pmid":"15221640","id":"PMC_15221640","title":"The IHPK1 gene is disrupted at the 3p21.31 breakpoint of t(3;9) in a family with type 2 diabetes mellitus.","date":"2004","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15221640","citation_count":28,"is_preprint":false},{"pmid":"26953345","id":"PMC_26953345","title":"Inositol Hexakisphosphate Kinase 1 (IP6K1) Regulates Inositol Synthesis in Mammalian Cells.","date":"2016","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/26953345","citation_count":27,"is_preprint":false},{"pmid":"28743739","id":"PMC_28743739","title":"IP6K1 is essential for chromatoid body formation and temporal regulation of Tnp2 and Prm2 expression in mouse spermatids.","date":"2017","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/28743739","citation_count":27,"is_preprint":false},{"pmid":"28577302","id":"PMC_28577302","title":"IP6K1 Reduces Mesenchymal Stem/Stromal Cell Fitness and Potentiates High Fat Diet-Induced Skeletal Involution.","date":"2017","source":"Stem cells (Dayton, Ohio)","url":"https://pubmed.ncbi.nlm.nih.gov/28577302","citation_count":25,"is_preprint":false},{"pmid":"29300979","id":"PMC_29300979","title":"High-Intensity Exercise Decreases IP6K1 Muscle Content and Improves Insulin Sensitivity (SI2*) in Glucose-Intolerant Individuals.","date":"2018","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/29300979","citation_count":23,"is_preprint":false},{"pmid":"35963434","id":"PMC_35963434","title":"Phosphatidic acid inhibits inositol synthesis by inducing nuclear translocation of kinase IP6K1 and repression of myo-inositol-3-P synthase.","date":"2022","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35963434","citation_count":21,"is_preprint":false},{"pmid":"20645182","id":"PMC_20645182","title":"Synthesis of InsP7 by the Inositol Hexakisphosphate Kinase 1 (IP6K1).","date":"2010","source":"Methods in molecular biology (Clifton, N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/20645182","citation_count":21,"is_preprint":false},{"pmid":"34229060","id":"PMC_34229060","title":"miR-125a-5p impairs the metastatic potential in breast cancer via IP6K1 targeting.","date":"2021","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/34229060","citation_count":21,"is_preprint":false},{"pmid":"31445853","id":"PMC_31445853","title":"Synthesis and characterization of novel isoform-selective IP6K1 inhibitors.","date":"2019","source":"Bioorganic & medicinal chemistry letters","url":"https://pubmed.ncbi.nlm.nih.gov/31445853","citation_count":17,"is_preprint":false},{"pmid":"34757046","id":"PMC_34757046","title":"Pleiotropic actions of IP6K1 mediate hepatic metabolic dysfunction to promote nonalcoholic fatty liver disease and steatohepatitis.","date":"2021","source":"Molecular metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/34757046","citation_count":16,"is_preprint":false},{"pmid":"38403246","id":"PMC_38403246","title":"Insights into the roles of inositol hexakisphosphate kinase 1 (IP6K1) in mammalian cellular processes.","date":"2024","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/38403246","citation_count":13,"is_preprint":false},{"pmid":"38317282","id":"PMC_38317282","title":"The Ip6k1 and Ip6k2 Kinases Are Critical for Normal Renal Tubular Function.","date":"2024","source":"Journal of the American Society of Nephrology : JASN","url":"https://pubmed.ncbi.nlm.nih.gov/38317282","citation_count":10,"is_preprint":false},{"pmid":"34841428","id":"PMC_34841428","title":"IP6K1 upregulates the formation of processing bodies by influencing protein-protein interactions on the mRNA cap.","date":"2021","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/34841428","citation_count":10,"is_preprint":false},{"pmid":"35216174","id":"PMC_35216174","title":"Whole Body Ip6k1 Deletion Protects Mice from Age-Induced Weight Gain, Insulin Resistance and Metabolic Dysfunction.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35216174","citation_count":9,"is_preprint":false},{"pmid":"35308129","id":"PMC_35308129","title":"Deletion of IP6K1 in mice accelerates tumor growth by dysregulating the tumor-immune microenvironment.","date":"2022","source":"Animal cells and systems","url":"https://pubmed.ncbi.nlm.nih.gov/35308129","citation_count":8,"is_preprint":false},{"pmid":"31593553","id":"PMC_31593553","title":"Platelet IP6K1 regulates neutrophil extracellular trap-microparticle complex formation in acute pancreatitis.","date":"2019","source":"JCI insight","url":"https://pubmed.ncbi.nlm.nih.gov/31593553","citation_count":7,"is_preprint":false},{"pmid":"39643078","id":"PMC_39643078","title":"Inhibiting IP6K1 confers atheroprotection by elevating circulating apolipoprotein A-I.","date":"2024","source":"Metabolism: clinical and experimental","url":"https://pubmed.ncbi.nlm.nih.gov/39643078","citation_count":5,"is_preprint":false},{"pmid":"39230924","id":"PMC_39230924","title":"Interaction with IP6K1 supports pyrophosphorylation of substrate proteins by the inositol pyrophosphate 5-InsP7.","date":"2024","source":"Bioscience reports","url":"https://pubmed.ncbi.nlm.nih.gov/39230924","citation_count":5,"is_preprint":false},{"pmid":"38350944","id":"PMC_38350944","title":"Deleting IP6K1 stabilizes neuronal sodium-potassium pumps and suppresses excitability.","date":"2024","source":"Molecular brain","url":"https://pubmed.ncbi.nlm.nih.gov/38350944","citation_count":2,"is_preprint":false},{"pmid":"39792359","id":"PMC_39792359","title":"IP6K1 Rewires LKB1 Signaling to Mediate Hyperglycemic Endothelial Senescence.","date":"2025","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/39792359","citation_count":1,"is_preprint":false},{"pmid":"38399478","id":"PMC_38399478","title":"Shaping the Future of Obesity Treatment: In Silico Multi-Modeling of IP6K1 Inhibitors for Obesity and Metabolic Dysfunction.","date":"2024","source":"Pharmaceuticals (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/38399478","citation_count":1,"is_preprint":false},{"pmid":"42053465","id":"PMC_42053465","title":"IP6K1 interacts with the syndecan SDC4 to support secretory granule biogenesis in gastric chief cells.","date":"2026","source":"American journal of physiology. Gastrointestinal and liver physiology","url":"https://pubmed.ncbi.nlm.nih.gov/42053465","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.06.17.659843","title":"Mammalian mitochondrial polyphosphate is regulated by the 5-InsP  <sub>7</sub>  synthase IP6K1","date":"2025-06-21","source":"bioRxiv","url":"https://doi.org/10.1101/2025.06.17.659843","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.01.20.633921","title":"Global Profiling of N-terminal Cysteine-Dependent Degradation Mechanisms","date":"2025-01-22","source":"bioRxiv","url":"https://doi.org/10.1101/2025.01.20.633921","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":17879,"output_tokens":5041,"usd":0.064626,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":13285,"output_tokens":5932,"usd":0.107362,"stage2_stop_reason":"end_turn"},"total_usd":0.171988,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"IP6K1 catalytic activity is required for cytoplasmic dynein-driven vesicle transport; IP7 pyrophosphorylates Ser51 in the dynein intermediate chain (IC), promoting IC interaction with the p150(Glued) subunit of dynactin, and cells lacking IP6K1 show decreased IC-p150(Glued) interaction and reduced IC recruitment to membranes.\",\n      \"method\": \"KO cells with rescue by active/inactive IP6K1, in vitro pyrophosphorylation assay, Co-IP, endosomal transport assays\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro pyrophosphorylation assay identifying specific substrate residue, active vs. inactive rescue, Co-IP, multiple orthogonal methods in single study\",\n      \"pmids\": [\"27474409\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"IP6K1 catalytic activity (5-IP7 synthesis) promotes cell migration and invasion via regulation of actin cytoskeleton dynamics and adhesion-dependent FAK/Paxillin signaling; expression of active but not inactive IP6K1 rescues migration defects in IP6K1 KO MEFs.\",\n      \"method\": \"KO MEFs with active/inactive IP6K1 rescue, gene expression analysis, immunoblot for FAK/Paxillin activation, migration/invasion assays\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — active vs. inactive rescue with specific signaling readouts, single lab, multiple methods\",\n      \"pmids\": [\"27140681\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"IP6K1 inhibits AMPK-mediated thermogenesis in adipocytes; adipocyte-specific Ip6k1 deletion enhances AMPK activation and thermogenic energy expenditure, and IP6 and IP6K1 differentially regulate upstream kinase-mediated AMPK stimulatory phosphorylation in vitro.\",\n      \"method\": \"Adipocyte-specific KO mice, in vitro AMPK phosphorylation assay, AMPK depletion rescue, thermogenesis/EE measurements, UCP1/PGC1α expression analysis\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro mechanistic assay plus conditional KO with AMPK depletion rescue, replicated across multiple temperature conditions and cell types\",\n      \"pmids\": [\"27701146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"IP6K1 preferentially binds the phospholipid phosphatidic acid (PA), and this PA binding is required for IP6K1 nuclear localization and negative regulation of myo-inositol-3-P synthase (MIPS/Isyna1) transcription, thereby suppressing inositol synthesis.\",\n      \"method\": \"Ip6k1 ablation, lipid-binding assay, subcellular fractionation/nuclear localization imaging, gene expression analysis of Isyna1\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — direct lipid-binding assay plus localization and transcriptional readout, single lab\",\n      \"pmids\": [\"26953345\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Plasma membrane-derived phosphatidic acid (PA), synthesized via the AMPK-PLD pathway, induces nuclear translocation of IP6K1 and represses MIPS protein expression; endoplasmic reticulum-derived PA does not induce IP6K1 translocation.\",\n      \"method\": \"Pharmacological PLD stimulation, direct PA supplementation, AMPK activation by glucose deprivation/valproate/lithium, subcellular localization imaging, MIPS immunoblot\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — multiple pharmacological tools with specific localization and protein-level readouts, single lab\",\n      \"pmids\": [\"35963434\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"IP6K1 is a component of the chromatoid body in round spermatids; its deletion leads to absence of chromatoid bodies, premature translational derepression of TNP2 and PRM2, and azoospermia in male mice.\",\n      \"method\": \"Ip6k1 KO mice, immunofluorescence localization, expression analysis of chromatoid body markers and spermatid-specific proteins\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization in spermatids combined with specific KO phenotype readouts, single lab\",\n      \"pmids\": [\"28743739\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"IP6K1 and IP6K2 together control synthesis of IP7 and IP8 in human cells and regulate phosphate homeostasis; inositol pyrophosphates bind to the SPX domain of the phosphate exporter XPR1 and regulate its activity, controlling both phosphate import and export.\",\n      \"method\": \"IP6K1/2 double KO in HCT116 cells, PAGE and HPLC analysis of inositol polyphosphates, nucleotide analysis, Malachite green assay, [32Pi] pulse labeling, SPX domain binding assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal biochemical methods (HPLC, radiolabeling, direct binding assay), genetic KO with functional rescue, single lab but rigorous\",\n      \"pmids\": [\"31186349\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"IP6K1 in platelets mediates inorganic polyphosphate (polyP) production; platelet-derived polyP is essential for neutrophil-platelet aggregate (NPA) formation and neutrophil accumulation in alveolar spaces during bacterial pneumonia, acting through the bradykinin pathway.\",\n      \"method\": \"Ip6k1 KO mice, platelet depletion, polyP rescue experiments, IP6K1 inhibitor TNP, serum polyP measurement, NPA quantification\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO, pharmacological inhibition, and polyP rescue in multiple bacterial infection models with specific mechanistic readouts\",\n      \"pmids\": [\"29618559\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"IP6K1 acts independently of its catalytic activity to upregulate P-body formation by binding to ribosomes and interacting with the mRNA decapping complex (EDC4, DCP1A/B, DCP2, DDX6), augmenting the DDX6-4E-T interaction on the 5' mRNA cap and promoting translational repression over initiation.\",\n      \"method\": \"IP6K1 KD/KO cells, active vs. inactive IP6K1 rescue, Co-IP of IP6K1 with ribosome and decapping complex components, P-body formation assays, miRNA-mediated suppression assays, DCP2-regulated transcript stability\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — Co-IP with multiple components, catalytic-dead rescue, functional readouts, single lab\",\n      \"pmids\": [\"34841428\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"IP6K1 interacts with the enzyme O-GlcNAcase in the liver; IP6K1 deletion reduces protein O-GlcNAcylation in mouse livers and in hepatocyte-specific KO mice.\",\n      \"method\": \"Co-immunoprecipitation, mass spectrometry, immunoblotting for O-GlcNAcylation in KO livers\",\n      \"journal\": \"Molecular metabolism\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP plus expression readout, single lab, limited mechanistic follow-up in abstract\",\n      \"pmids\": [\"34757046\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"IP6K1 binds to apoA-I and, via its product 5PP-InsP5, induces apoA-I degradation requiring ubiquitination factor E4A (UBE4A); depleting 5PP-InsP5 by IP6K1 deletion disrupts UBE4A-apoA-I interaction, preventing apoA-I degradation and increasing circulating apoA-I levels.\",\n      \"method\": \"Co-immunoprecipitation, chemical biology tools for 5PP-InsP5 binding, hepatocyte-specific IP6K1 KO mice, IP6K1/apoA-I double KO validation\",\n      \"journal\": \"Metabolism: clinical and experimental\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifying binding partners, chemical biology for pyrophosphate-protein interaction, genetic validation in vivo, single lab\",\n      \"pmids\": [\"39643078\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"IP6K1 interacts with substrate proteins targeted for 5-InsP7-mediated pyrophosphorylation (including NOLC1, TCOF, UBF1, AP3B1) and with CK2 kinase; a trimeric complex of IP6K1-AP3B1-CK2α was demonstrated, and disrupting IP6K1 binding to AP3B1 lowers AP3B1 pyrophosphorylation in vivo, supporting coordinated pre-phosphorylation and pyrophosphorylation.\",\n      \"method\": \"Mass spectrometry interactome, Co-IP of trimeric complex, disruption of IP6K1-AP3B1 binding with in vivo pyrophosphorylation readout\",\n      \"journal\": \"Bioscience reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — MS interactome plus Co-IP of trimeric complex plus functional disruption assay, single lab\",\n      \"pmids\": [\"39230924\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"IP6K1-generated 5-InsP7 governs the degradation of Na+/K+-ATPase (NKA) via the autoinhibitory domain of PI3K p85α; IP6K1 KO neurons show enriched NKA, lower action potential frequency, and deeper afterhyperpolarization, demonstrating that IP6K1 regulates neuronal excitability through NKA stability.\",\n      \"method\": \"IP6K1 KO mouse neurons, whole-cell electrophysiology, action potential recording\",\n      \"journal\": \"Molecular brain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct electrophysiological readout in KO neurons consistent with proposed NKA mechanism, single lab, mechanism cited from prior work\",\n      \"pmids\": [\"38350944\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"IP6K1 mediates hyperglycemia-induced endothelial senescence by stabilizing LKB1 (by disrupting Hsp/Hsc70 and CHIP-mediated LKB1 degradation) and switching LKB1 signaling from AMPK activation to p53 pathway activation; endothelial-specific IP6K1 deletion attenuates this senescence.\",\n      \"method\": \"Endothelial-specific IP6K1 KO and OE mice, Co-IP of LKB1 with Hsp70/CHIP and p53, phosphorylation assays for AMPK vs. p53 targets\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific KO/OE with mechanistic Co-IP, pathway switching assay, single lab\",\n      \"pmids\": [\"39792359\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"IP6K1 and IP6K2 are required for normal expression and function of the renal Na+/Pi cotransporters NaPi-IIa and NaPi-IIc; renal tubular-specific double KO mice show downregulation of NaPi-IIa/IIc, reduced proximal tubule phosphate uptake, and hypophosphatemia.\",\n      \"method\": \"Renal tubular-specific Ip6k1/2 double KO mice, in vitro opossum kidney cells with depletion, mRNA/protein expression assays, brush border membrane phosphate uptake assay\",\n      \"journal\": \"Journal of the American Society of Nephrology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — tissue-specific KO with functional transport assay and expression readouts, two model systems, but IP6K1 and IP6K2 studied together, not individually\",\n      \"pmids\": [\"38317282\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"IP6K1 platelet activity regulates NET-microparticle complex formation in acute pancreatitis; IP6K1-deficient platelets fail to support thrombin-induced NET formation when mixed with wild-type neutrophils, and polyphosphate rescue restores NET formation.\",\n      \"method\": \"IP6K1 KO mice, platelet-neutrophil mixing experiments, polyphosphate rescue, electron microscopy, STAT-3 phosphorylation assay\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with polyphosphate rescue, mechanistic dissection of platelet-neutrophil interaction, single lab\",\n      \"pmids\": [\"31593553\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"IP6K1 interacts with the proteoglycan syndecan-4 (SDC4) to support secretory granule biogenesis in gastric chief cells; this function is independent of IP6K1 catalytic activity, as both active and inactive IP6K1 rescue pepsinogen C (PGC) granule formation in IP6K1 KO AGS cells.\",\n      \"method\": \"Ip6k1 KO mice, CRISPR KO in AGS cells, active/inactive IP6K1 rescue, Co-IP/interactome for SDC4, colocalization of SDC4 with PGC granules\",\n      \"journal\": \"American journal of physiology. Gastrointestinal and liver physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — catalytic-dead rescue establishing activity-independence, Co-IP of SDC4, CRISPR model plus mouse model, single lab\",\n      \"pmids\": [\"42053465\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"IP6K1-generated 5-InsP7 regulates mitochondrial polyphosphate (polyP) levels; IP6K1 KO cells and mice show reduced mitochondrial polyP, impaired mitochondrial respiration and membrane potential; expression of catalytically active but not inactive IP6K1 restores mitochondrial polyP and membrane potential, while both active and inactive forms rescue mitochondrial respiration.\",\n      \"method\": \"IP6K1 KO cells and mice, DAPI fluorescence-based polyP quantification, mitochondrial fractionation, active/inactive IP6K1 rescue, mitochondrial respiration and membrane potential assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — active vs. inactive rescue dissecting catalytic from non-catalytic functions, quantitative polyP assay in fractionated compartments, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.06.17.659843\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"IP6K1 is a substrate of the Cys-Arg/N-degron pathway under hypoxia; loss of IP6K1 impairs glucose uptake, glycolytic ATP production, and mitochondrial morphology and function, disrupting metabolic adaptation under hypoxic conditions.\",\n      \"method\": \"Systematic proteomics/N-degron pathway screen, IP6K1 KO cells under hypoxia, glucose uptake and metabolic flux assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — proteomics screen identifying IP6K1 as substrate, KO phenotype, single lab, preprint, limited mechanistic detail for IP6K1 specifically\",\n      \"pmids\": [\"bio_10.1101_2025.01.20.633921\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Recombinant mouse IP6K1 purified from E. coli synthesizes InsP7 (5-IP7) from IP6 in vitro, and this purified enzyme can pyrophosphorylate protein substrates from different species, establishing IP6K1's enzymatic activity and its product as a protein-modifying agent.\",\n      \"method\": \"Recombinant protein purification from E. coli, in vitro kinase assay with cold and [32P]-labeled substrates, protein pyrophosphorylation assay\",\n      \"journal\": \"Methods in molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in vitro reconstitution of enzymatic activity with purified recombinant protein and radiolabeled substrate\",\n      \"pmids\": [\"20645182\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"IP6K1 is an inositol hexakisphosphate kinase that converts IP6 to the inositol pyrophosphate 5-IP7, which regulates diverse cellular processes including dynein-driven vesicle transport (via pyrophosphorylation of dynein IC Ser51), AMPK-mediated thermogenesis and energy metabolism, cellular phosphate homeostasis (through XPR1 SPX domain binding and renal NaPi cotransporter regulation), P-body formation, inositol synthesis (via PA-dependent nuclear translocation and MIPS repression), apoA-I stability (via UBE4A), LKB1-p53 endothelial senescence signaling, mitochondrial polyphosphate production, and secretory granule biogenesis—with some functions (P-body formation, secretory granule biogenesis) shown to be independent of its catalytic activity.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"IP6K1 is an inositol hexakisphosphate kinase that synthesizes the inositol pyrophosphate 5-IP7 (5-InsP7) from IP6, and the enzyme's product serves as a protein-modifying agent capable of pyrophosphorylating protein substrates in vitro [#19]. Through 5-IP7-mediated pyrophosphorylation, IP6K1 controls intracellular trafficking — pyrophosphorylating Ser51 of the dynein intermediate chain to promote its interaction with the dynactin p150(Glued) subunit and drive vesicle transport [#0] — and it physically organizes substrate pyrophosphorylation by assembling with the priming kinase CK2 and target proteins such as AP3B1 into a coordinated pre-phosphorylation/pyrophosphorylation complex [#11]. A major theme is metabolic and phosphate regulation: IP6K1 (together with IP6K2) governs cellular inositol pyrophosphate pools that bind the SPX domain of the phosphate exporter XPR1 to set phosphate homeostasis [#6] and is required for renal Na+/Pi cotransporter expression and proximal tubule phosphate uptake [#14]. In adipocytes IP6K1 restrains AMPK-mediated thermogenesis and energy expenditure [#2], and its catalytic activity supports mitochondrial polyphosphate production, respiration, and membrane potential [#17]. IP6K1 also acts non-catalytically: it binds ribosomes and the mRNA decapping complex to promote P-body formation and translational repression [#8], and interacts with syndecan-4 to support secretory granule biogenesis, with both active and inactive enzyme rescuing these functions [#16]. Additional 5-IP7-dependent roles include UBE4A-mediated apoA-I degradation [#10], LKB1 stabilization that switches signaling toward p53 in hyperglycemia-induced endothelial senescence [#13], and regulation of neuronal Na+/K+-ATPase stability and excitability [#12]. IP6K1 is essential for chromatoid body assembly and spermatogenesis [#5] and for platelet polyphosphate production driving neutrophil-platelet aggregates and NET formation in infection and inflammation [#7, #15].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established the foundational biochemistry: that IP6K1 is an enzyme generating 5-IP7 and that this product can covalently modify proteins by pyrophosphorylation.\",\n      \"evidence\": \"Recombinant mouse IP6K1 from E. coli with in vitro kinase and protein pyrophosphorylation assays using radiolabeled substrates\",\n      \"pmids\": [\"20645182\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify physiological protein substrates\", \"No cellular phenotype linked to enzymatic output\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Connected IP6K1 catalytic output to specific cellular machinery by identifying a defined pyrophosphorylation substrate residue controlling motor-adaptor coupling and vesicle transport.\",\n      \"evidence\": \"KO cells with active/inactive rescue, in vitro pyrophosphorylation of dynein IC Ser51, Co-IP and endosomal transport assays\",\n      \"pmids\": [\"27474409\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and reversibility of Ser51 pyrophosphorylation in vivo not defined\", \"Other dynein-cargo specificities not addressed\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Defined IP6K1 as a metabolic brake on thermogenesis, showing its catalytic activity opposes AMPK activation and energy expenditure in adipose tissue.\",\n      \"evidence\": \"Adipocyte-specific KO mice, in vitro AMPK phosphorylation assay with AMPK depletion rescue, thermogenesis measurements\",\n      \"pmids\": [\"27701146\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct molecular link between 5-IP7 and the upstream AMPK kinase not fully resolved\", \"Tissue-autonomous vs systemic contributions not separated\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Revealed a lipid-sensing input to IP6K1 localization: PA binding drives nuclear translocation to repress inositol synthesis, creating a feedback loop on substrate availability.\",\n      \"evidence\": \"Ip6k1 ablation, lipid-binding assay, nuclear localization imaging, Isyna1/MIPS transcriptional readout; later extended with PLD/AMPK pharmacology\",\n      \"pmids\": [\"26953345\", \"35963434\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct PA-IP6K1 binding interface not mapped\", \"Mechanism of MIPS transcriptional/protein-level repression by nuclear IP6K1 unresolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Linked IP6K1 catalytic activity to cytoskeletal dynamics and adhesion signaling underlying cell migration.\",\n      \"evidence\": \"KO MEFs with active/inactive rescue, FAK/Paxillin immunoblot, migration and invasion assays\",\n      \"pmids\": [\"27140681\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct 5-IP7 substrate in the FAK/Paxillin axis identified\", \"Single cell-type model\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrated an essential developmental role in male germ cells via chromatoid body assembly and translational control.\",\n      \"evidence\": \"Ip6k1 KO mice, immunofluorescence of chromatoid body markers, TNP2/PRM2 expression analysis\",\n      \"pmids\": [\"28743739\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether the chromatoid body role is catalytic or structural not dissected\", \"Molecular partners in the chromatoid body unidentified\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Established IP6K1 as a producer of platelet inorganic polyphosphate driving innate immune aggregate formation in infection.\",\n      \"evidence\": \"Ip6k1 KO mice, platelet depletion, polyP rescue, IP6K1 inhibitor TNP, NPA quantification in bacterial pneumonia\",\n      \"pmids\": [\"29618559\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Enzymatic mechanism linking 5-IP7 to polyP synthesis not defined\", \"Bradykinin pathway connection mechanistically incomplete\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended the platelet polyP role to NET-microparticle complex formation, showing IP6K1-dependent platelet support of neutrophil function.\",\n      \"evidence\": \"IP6K1 KO mice, platelet-neutrophil mixing, polyP rescue, electron microscopy, STAT-3 phosphorylation\",\n      \"pmids\": [\"31593553\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular effector of polyP on NET formation unresolved\", \"Single disease model (pancreatitis)\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Placed IP6K1 at the center of cellular phosphate homeostasis by linking its inositol pyrophosphate products to SPX-domain regulation of the XPR1 phosphate exporter.\",\n      \"evidence\": \"IP6K1/2 double KO in HCT116, HPLC and radiolabeling of inositol pyrophosphates, SPX domain binding assay\",\n      \"pmids\": [\"31186349\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Individual IP6K1 vs IP6K2 contribution not separated\", \"Whether IP6K1 directly contacts XPR1 vs acts through diffusible 5-IP7 unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Uncovered a catalysis-independent function: IP6K1 scaffolds ribosomes and the decapping complex to promote P-body formation and translational repression.\",\n      \"evidence\": \"KD/KO cells, active/inactive rescue, Co-IP with ribosome and EDC4/DCP1A-B/DCP2/DDX6, P-body and miRNA suppression assays\",\n      \"pmids\": [\"34841428\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binding interface within the decapping complex not mapped\", \"How a catalytic kinase performs a structural scaffolding role unexplained\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified a hepatic interaction with O-GlcNAcase linking IP6K1 to protein O-GlcNAcylation.\",\n      \"evidence\": \"Co-IP, mass spectrometry, O-GlcNAcylation immunoblot in KO livers\",\n      \"pmids\": [\"34757046\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single Co-IP plus expression readout without reciprocal validation\", \"Mechanism by which IP6K1 affects O-GlcNAcase activity unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed how IP6K1 organizes substrate pyrophosphorylation by forming a CK2-IP6K1-substrate complex coupling priming phosphorylation to pyrophosphorylation.\",\n      \"evidence\": \"MS interactome, Co-IP of IP6K1-AP3B1-CK2alpha trimer, disruption of IP6K1-AP3B1 binding with in vivo pyrophosphorylation readout\",\n      \"pmids\": [\"39230924\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Generality of the trimeric complex across substrates not established\", \"Structural basis of substrate selection unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined a 5PP-InsP5/UBE4A-dependent pathway controlling apoA-I degradation and circulating lipoprotein levels.\",\n      \"evidence\": \"Co-IP, chemical biology tools for 5PP-InsP5 binding, hepatocyte-specific KO and IP6K1/apoA-I double KO mice\",\n      \"pmids\": [\"39643078\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether apoA-I pyrophosphorylation directly triggers UBE4A recruitment not shown\", \"Ubiquitination steps downstream of UBE4A undefined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Established a renal physiological role in phosphate reabsorption via control of NaPi cotransporter expression.\",\n      \"evidence\": \"Renal tubular-specific Ip6k1/2 double KO mice and opossum kidney cells, expression assays, brush border phosphate uptake\",\n      \"pmids\": [\"38317282\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"IP6K1 and IP6K2 studied jointly, not individually\", \"Mechanism linking inositol pyrophosphates to NaPi-IIa/IIc expression unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Linked IP6K1 catalytic output to neuronal excitability through 5-InsP7-governed Na+/K+-ATPase stability.\",\n      \"evidence\": \"IP6K1 KO mouse neurons, whole-cell electrophysiology and action potential recording\",\n      \"pmids\": [\"38350944\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The PI3K p85alpha autoinhibitory mechanism cited from prior work, not directly demonstrated here\", \"Direct NKA pyrophosphorylation in neurons not shown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Revealed a pathological signaling switch in which IP6K1 stabilizes LKB1 and redirects its output from AMPK toward p53 to drive endothelial senescence in hyperglycemia.\",\n      \"evidence\": \"Endothelial-specific KO/OE mice, Co-IP of LKB1 with Hsp70/CHIP and p53, AMPK vs p53 phosphorylation assays\",\n      \"pmids\": [\"39792359\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether LKB1 stabilization requires direct pyrophosphorylation not established\", \"Molecular determinant of the AMPK-to-p53 switch unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected IP6K1 catalytic activity to mitochondrial polyphosphate, respiration, and membrane potential, while separating catalytic from non-catalytic contributions to mitochondrial function.\",\n      \"evidence\": \"IP6K1 KO cells and mice, DAPI polyP quantification in mitochondrial fractions, active/inactive rescue, respiration and membrane potential assays (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.06.17.659843\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint not yet peer-reviewed\", \"Mechanism by which 5-InsP7 promotes mitochondrial polyP synthesis undefined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified IP6K1 itself as a regulated substrate of the Cys-Arg/N-degron pathway under hypoxia, linking its stability to metabolic adaptation.\",\n      \"evidence\": \"Proteomics/N-degron screen, IP6K1 KO cells under hypoxia, glucose uptake and metabolic flux assays (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.01.20.633921\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Preprint with limited IP6K1-specific mechanistic detail\", \"Degron sequence and E3 ligase for IP6K1 not defined\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Established a further catalysis-independent role in secretory granule biogenesis through interaction with syndecan-4.\",\n      \"evidence\": \"Ip6k1 KO mice, CRISPR KO AGS cells, active/inactive rescue, Co-IP/interactome for SDC4, colocalization with PGC granules\",\n      \"pmids\": [\"42053465\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of IP6K1-SDC4 interaction unmapped\", \"How the interaction promotes granule biogenesis mechanistically unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How IP6K1's catalytic (5-IP7 pyrophosphorylation) and non-catalytic (scaffolding) functions are partitioned and coordinated across its many cellular roles remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying structural model distinguishing catalytic vs scaffold modes\", \"Tissue-specific substrate repertoire of 5-IP7 incompletely defined\", \"Regulation of IP6K1 subcellular localization and stability across contexts incomplete\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [19, 0, 6]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 11, 19]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [8, 0]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [17]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [6, 14]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [2, 17]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [8]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 16]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [7, 15]}\n    ],\n    \"complexes\": [\n      \"IP6K1-AP3B1-CK2alpha complex\",\n      \"mRNA decapping complex (EDC4/DCP1A-B/DCP2/DDX6)\",\n      \"chromatoid body\"\n    ],\n    \"partners\": [\n      \"AP3B1\",\n      \"CK2alpha\",\n      \"DDX6\",\n      \"EDC4\",\n      \"UBE4A\",\n      \"LKB1\",\n      \"SDC4\",\n      \"XPR1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}