{"id":"e8ea73b7-e161-5c55-a9b3-dc6f6ca7f889","stable_key":"104835a3-b891-5dc4-a6bb-42ab7c6f96c4:butyrate-hcar2-agonism","predicate":"activates","statement":"Butyrate activated GPR109A/HCAR2 at millimolar concentrations in the study of receptor signaling in human colonic cells.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"a17b9797-6718-5c56-a58a-d76c109f7dc4","mechanism_event_label":"A receptor also used by nicotinic acid senses sufficiently high local butyrate.","subject":{"id":"e7428a7f-d35a-5406-9904-a88984814833","slug":"butyrate","display_name":"Butyrate","entity_type_key":"small_molecule"},"object":{"id":"c31b5501-5abf-57bb-8324-15923ed678cf","slug":"hcar2","display_name":"Human hydroxycarboxylic acid receptor 2 / HCAR2","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"a17b9797-6718-5c56-a58a-d76c109f7dc4","stable_key":"104835a3-b891-5dc4-a6bb-42ab7c6f96c4:butyrate-hcar2-agonism-event","event_type":"observed_relationship","label":"A receptor also used by nicotinic acid senses sufficiently high local butyrate.","description":"Butyrate activated GPR109A/HCAR2 at millimolar concentrations in the study of receptor signaling in human colonic cells.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"e7428a7f-d35a-5406-9904-a88984814833","slug":"butyrate","display_name":"Butyrate","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"c31b5501-5abf-57bb-8324-15923ed678cf","slug":"hcar2","display_name":"Human hydroxycarboxylic acid receptor 2 / HCAR2","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9751fdb6-9b30-586f-b07a-79b8e2cd62dd","slug":"nicotinic-acid","display_name":"Nicotinic acid","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human receptor/cell assays with separate mouse tissue observations.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Low affinity makes exposure compartment important; sharing a receptor does not make butyrate and niacin nutritionally interchangeable.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Butyrate collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"butyrate","display_name":"Butyrate","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A receptor also used by nicotinic acid senses sufficiently high local butyrate.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"GPR109A is a G-protein-coupled receptor for the bacterial fermentation product butyrate and functions as a tumor suppressor in colon. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19276343/ · DOI 10.1158/0008-5472.CAN-08-4466","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"93e37208-7bcc-5991-9043-d063ff4b4f7c","evidence_kind":"source_excerpt","locator":"Lines 350-356","start_line":350,"end_line":356,"excerpt":"## butyrate-hcar2-agonism\nA receptor also used by nicotinic acid senses sufficiently high local butyrate.\nButyrate activated GPR109A/HCAR2 at millimolar concentrations in the study of receptor signaling in human colonic cells.\nModel: Human receptor/cell assays with separate mouse tissue observations.\nLimitations: Low affinity makes exposure compartment important; sharing a receptor does not make butyrate and niacin nutritionally interchangeable.\nEvidence access: Primary abstract\nGPR109A is a G-protein-coupled receptor for the bacterial fermentation product butyrate and functions as a tumor suppressor in colon. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19276343/ · DOI 10.1158/0008-5472.CAN-08-4466","model_system":"Human receptor/cell assays with separate mouse tissue observations.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"33205bb8-dcbe-5d2c-afca-86075d7748d1","stable_key":"import-104835a3-b891-5dc4-a6bb-42ab7c6f96c4","title":"Butyrate: microbial production, fuel use, signaling and nutrient interactions (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary-abstract references and experimental limitations individually identified. 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