{"id":"931f49cc-66a6-57fc-b626-1697704f4b54","stable_key":"fe6af7fc-7372-5c4f-9c2f-2bbf56695397:phosphorus-pcyt-cdp","predicate":"increases","statement":"Human CCTbeta expression increased CCT activity and cellular CDP-choline accumulation in COS-7 cells.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"743d4bee-60f6-5152-aaeb-ff58afc62f31","mechanism_event_label":"A separately identified enzyme activates the phosphocholine building block.","subject":{"id":"1d30b402-b160-5841-8709-28efc300372b","slug":"pcyt1b","display_name":"Human CTP:phosphocholine cytidylyltransferase beta / PCYT1B","entity_type_key":"protein"},"object":{"id":"e1f22bfd-771d-5405-b2d4-ff5f4ae4d95f","slug":"cdp-choline","display_name":"CDP-choline","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"743d4bee-60f6-5152-aaeb-ff58afc62f31","stable_key":"fe6af7fc-7372-5c4f-9c2f-2bbf56695397:phosphorus-pcyt-cdp-event","event_type":"biochemical_relationship","label":"A separately identified enzyme activates the phosphocholine building block.","description":"Human CCTbeta expression increased CCT activity and cellular CDP-choline accumulation in COS-7 cells.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"2159176b-2e94-5403-98e9-97e966b38b81","slug":"phosphocholine","display_name":"Phosphocholine","entity_type_key":"small_molecule"},"role":"pathway_substrate","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"1d30b402-b160-5841-8709-28efc300372b","slug":"pcyt1b","display_name":"Human CTP:phosphocholine cytidylyltransferase beta / PCYT1B","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"e1f22bfd-771d-5405-b2d4-ff5f4ae4d95f","slug":"cdp-choline","display_name":"CDP-choline","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/phosphorus-research/9593753.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45\", \"start_char\": 0, \"end_char\": 1766, \"text_sha256\": \"6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human isoform cloning and COS-7 expression studies","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"CCTbeta transfection and catalytic assays with lipid regulators","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Expression-system findings; maximum activity required lipid regulators. Do not generalize the early clone to every subsequently described splice variant.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Phosphorus research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"phosphorus","display_name":"Phosphorus","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Human PCYT1B expressed in African-green-monkey-derived COS-7 cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A separately identified enzyme activates the phosphocholine building block.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[phosphorus-p9593753] Cloning and characterization of a second human CTP:phosphocholine cytidylyltransferase. (1998). https://pubmed.ncbi.nlm.nih.gov/9593753/ DOI: 10.1074/jbc.273.22.14022","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cytoplasm and phospholipid biosynthesis","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9f221ed5-65ca-579f-b371-b3d40b63746d","evidence_kind":"source_excerpt","locator":"Lines 698-709","start_line":698,"end_line":709,"excerpt":"### phosphorus-pcyt-cdp\nHuman CCTbeta expression increased CCT activity and cellular CDP-choline accumulation in COS-7 cells.\nCondition category: normal\nnutrient_topic: Phosphorus research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A separately identified enzyme activates the phosphocholine building block.\norganism: Human PCYT1B expressed in African-green-monkey-derived COS-7 cells\ntissue_or_cell_type: Cytoplasm and phospholipid biosynthesis\nexperimental_model: Human isoform cloning and COS-7 expression studies\nlimitations: Expression-system findings; maximum activity required lipid regulators. Do not generalize the early clone to every subsequently described splice variant.\nexposure: CCTbeta transfection and catalytic assays with lipid regulators\nevidence_span: {\"source_cache\": \"artifacts/phosphorus-research/9593753.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45\", \"start_char\": 0, \"end_char\": 1766, \"text_sha256\": \"6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45\"}\n[phosphorus-p9593753] Cloning and characterization of a second human CTP:phosphocholine cytidylyltransferase. (1998). https://pubmed.ncbi.nlm.nih.gov/9593753/ DOI: 10.1074/jbc.273.22.14022","model_system":"Human isoform cloning and COS-7 expression studies","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [phosphorus-p9593753] Cloning and characterization of a second human CTP:phosphocholine cytidylyltransferase. (1998). https://pubmed.ncbi.nlm.nih.gov/9593753/ DOI: 10.1074/jbc.273.22.14022","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"cfdefe70-3a09-5e2e-97c8-46626382e4b4","stable_key":"import-fe6af7fc-7372-5c4f-9c2f-2bbf56695397","title":"Phosphorus: metabolism, signaling and nutrient connections (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":"a04956d7177582b749608db404e6b691ae3b28a9f2f762781b6d820b461044fb","revision_id":"713b78f5-1133-5b2b-8822-20c0852e3715","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}