{"id":"4f2617b5-c2f4-5c77-87c8-09860ab88eee","stable_key":"e69ef6a0-0e23-5eac-aca1-cf333781b962:ino-pi-ppip-phosphatase","predicate":"inhibits_phosphatase_activity_of","statement":"Inorganic phosphate inhibited PPIP5K InsP8 phosphatase activities by approximately 40–90% across 0–1 mM in the reported assays.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"35d3098c-6f34-58a2-ad1d-f4ee6549ba31","mechanism_event_label":"Phosphate availability can slow destruction of the inositol-pyrophosphate signal.","subject":{"id":"b28dfc54-a5ef-5f9e-ac1f-890b68e58dc3","slug":"inorganic-phosphate","display_name":"Inorganic phosphate","entity_type_key":"chemical_species"},"object":{"id":"31dea946-81f2-55a5-a123-cf85a8faec20","slug":"ppip5k-family","display_name":"Diphosphoinositol pentakisphosphate kinase family","entity_type_key":"protein_family"},"evidence_count":1,"mechanism_event":{"id":"35d3098c-6f34-58a2-ad1d-f4ee6549ba31","stable_key":"e69ef6a0-0e23-5eac-aca1-cf333781b962:ino-pi-ppip-phosphatase-event","event_type":"biochemical_relationship","label":"Phosphate availability can slow destruction of the inositol-pyrophosphate signal.","description":"Inorganic phosphate inhibited PPIP5K InsP8 phosphatase activities by approximately 40–90% across 0–1 mM in the reported assays.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"b28dfc54-a5ef-5f9e-ac1f-890b68e58dc3","slug":"inorganic-phosphate","display_name":"Inorganic phosphate","entity_type_key":"chemical_species"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"31dea946-81f2-55a5-a123-cf85a8faec20","slug":"ppip5k-family","display_name":"Diphosphoinositol pentakisphosphate kinase family","entity_type_key":"protein_family"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/inositol-research/28126903.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"6f5c96ed7d02591d5fe475d0e26aa2f21dc93f0c86c12998debb417f98254d2f\", \"start_char\": 0, \"end_char\": 1981, \"text_sha256\": \"6f5c96ed7d02591d5fe475d0e26aa2f21dc93f0c86c12998debb417f98254d2f\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Cellular phosphate withdrawal/repletion and bifunctional enzyme kinetics","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Phosphate availability and PPIP5K kinase/phosphatase assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Cell-culture nutrient withdrawal is not a measured human dietary threshold; PPIP5K isoforms are not identical.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Inositol research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"inositol","display_name":"Inositol (stereoisomer family)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Human HCT116 cells and human PPIP5K proteins","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Phosphate availability can slow destruction of the inositol-pyrophosphate signal.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[ino-p28126903] The Significance of the Bifunctional Kinase/Phosphatase Activities of Diphosphoinositol Pentakisphosphate Kinases (PPIP5Ks) for Coupling Inositol Pyrophosphate Cell Signaling to Cellular Phosphate Homeostasis. (2017). https://pubmed.ncbi.nlm.nih.gov/28126903/ DOI: 10.1074/jbc.m116.765743","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Intestinal tumor-derived cell line; purified enzymes","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"6bd50658-cfa8-50f2-bb70-e6716fdff6ee","evidence_kind":"source_excerpt","locator":"Lines 834-845","start_line":834,"end_line":845,"excerpt":"### ino-pi-ppip-phosphatase\nInorganic phosphate inhibited PPIP5K InsP8 phosphatase activities by approximately 40–90% across 0–1 mM in the reported assays.\nCondition category: normal\nnutrient_topic: Inositol research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Phosphate availability can slow destruction of the inositol-pyrophosphate signal.\norganism: Human HCT116 cells and human PPIP5K proteins\ntissue_or_cell_type: Intestinal tumor-derived cell line; purified enzymes\nexperimental_model: Cellular phosphate withdrawal/repletion and bifunctional enzyme kinetics\nlimitations: Cell-culture nutrient withdrawal is not a measured human dietary threshold; PPIP5K isoforms are not identical.\nexposure: Phosphate availability and PPIP5K kinase/phosphatase assays\nevidence_span: {\"source_cache\": \"artifacts/inositol-research/28126903.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"6f5c96ed7d02591d5fe475d0e26aa2f21dc93f0c86c12998debb417f98254d2f\", \"start_char\": 0, \"end_char\": 1981, \"text_sha256\": \"6f5c96ed7d02591d5fe475d0e26aa2f21dc93f0c86c12998debb417f98254d2f\"}\n[ino-p28126903] The Significance of the Bifunctional Kinase/Phosphatase Activities of Diphosphoinositol Pentakisphosphate Kinases (PPIP5Ks) for Coupling Inositol Pyrophosphate Cell Signaling to Cellular Phosphate Homeostasis. (2017). https://pubmed.ncbi.nlm.nih.gov/28126903/ DOI: 10.1074/jbc.m116.765743","model_system":"Cellular phosphate withdrawal/repletion and bifunctional enzyme kinetics","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [ino-p28126903] The Significance of the Bifunctional Kinase/Phosphatase Activities of Diphosphoinositol Pentakisphosphate Kinases (PPIP5Ks) for Coupling Inositol Pyrophosphate Cell Signaling to Cellular Phosphate Homeostasis. (2017). https://pubmed.ncbi.nlm.nih.gov/28126903/ DOI: 10.1074/jbc.m116.765743","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"d590c659-b774-50e6-9f1d-aff61d5f7c9c","stable_key":"import-e69ef6a0-0e23-5eac-aca1-cf333781b962","title":"Inositol: synthesis, signaling, mineral interactions and conditional deficiency (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"f7adbcedad647d5f8a3cc9e46bfa515e83c508be9c2a4e9d59c5f5dfb0667d53","revision_id":"a82d187c-60fb-52d1-8482-eadb92860f33","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}