{"id":"c73a5280-1b4e-5373-a84c-3d67af0d634e","stable_key":"4df6a932-097e-563a-91fe-5dceec471ffd:chloride-cftr-channel","predicate":"conducts","statement":"CFTR pore-region mutations changed anion selectivity, demonstrating that CFTR forms an anion channel.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"bbedd4c5-d81b-52d3-b411-766ecffa0354","mechanism_event_label":"CFTR provides a route through which chloride can cross a membrane.","subject":{"id":"53064670-c3d1-59e8-aeaa-a8d673d00f3a","slug":"cftr","display_name":"Human cystic fibrosis transmembrane conductance regulator / CFTR","entity_type_key":"protein"},"object":{"id":"6f35aa38-f875-5759-b749-97a2f6480ff3","slug":"chloride-ion","display_name":"Chloride ion","entity_type_key":"ion"},"evidence_count":1,"mechanism_event":{"id":"bbedd4c5-d81b-52d3-b411-766ecffa0354","stable_key":"4df6a932-097e-563a-91fe-5dceec471ffd:chloride-cftr-channel-event","event_type":"biochemical_relationship","label":"CFTR provides a route through which chloride can cross a membrane.","description":"CFTR pore-region mutations changed anion selectivity, demonstrating that CFTR forms an anion channel.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"53064670-c3d1-59e8-aeaa-a8d673d00f3a","slug":"cftr","display_name":"Human cystic fibrosis transmembrane conductance regulator / CFTR","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"6f35aa38-f875-5759-b749-97a2f6480ff3","slug":"chloride-ion","display_name":"Chloride ion","entity_type_key":"ion"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/chloride-research/1712984.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d35ab648c3b60da00912ec5a2921115c14aa33b138ed2aa408e66d5153aa9d3b\", \"start_char\": 0, \"end_char\": 849, \"text_sha256\": \"d35ab648c3b60da00912ec5a2921115c14aa33b138ed2aa408e66d5153aa9d3b\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"CFTR expression and pore-residue mutagenesis","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"K95 or K335 substitutions","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Selectivity experiment; not a supplementation study.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Chloride research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"chloride","display_name":"Chloride","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Human CFTR in expression systems","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"CFTR provides a route through which chloride can cross a membrane.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[chloride-p1712984] Demonstration that CFTR is a chloride channel by alteration of its anion selectivity. (1991). https://pubmed.ncbi.nlm.nih.gov/1712984/ DOI: 10.1126/science.1712984","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell plasma membrane","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"da635222-f18d-5513-8c6e-48674a9d5869","evidence_kind":"source_excerpt","locator":"Lines 224-235","start_line":224,"end_line":235,"excerpt":"### chloride-cftr-channel\nCFTR pore-region mutations changed anion selectivity, demonstrating that CFTR forms an anion channel.\nCondition category: normal\nnutrient_topic: Chloride research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: CFTR provides a route through which chloride can cross a membrane.\norganism: Human CFTR in expression systems\ntissue_or_cell_type: Cell plasma membrane\nexperimental_model: CFTR expression and pore-residue mutagenesis\nlimitations: Selectivity experiment; not a supplementation study.\nexposure: K95 or K335 substitutions\nevidence_span: {\"source_cache\": \"artifacts/chloride-research/1712984.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d35ab648c3b60da00912ec5a2921115c14aa33b138ed2aa408e66d5153aa9d3b\", \"start_char\": 0, \"end_char\": 849, \"text_sha256\": \"d35ab648c3b60da00912ec5a2921115c14aa33b138ed2aa408e66d5153aa9d3b\"}\n[chloride-p1712984] Demonstration that CFTR is a chloride channel by alteration of its anion selectivity. (1991). https://pubmed.ncbi.nlm.nih.gov/1712984/ DOI: 10.1126/science.1712984","model_system":"CFTR expression and pore-residue mutagenesis","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [chloride-p1712984] Demonstration that CFTR is a chloride channel by alteration of its anion selectivity. (1991). https://pubmed.ncbi.nlm.nih.gov/1712984/ DOI: 10.1126/science.1712984","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"1c2070d5-9f15-5945-b325-d0b49a32c04b","stable_key":"import-4df6a932-097e-563a-91fe-5dceec471ffd","title":"Chloride: transport, acid-base balance, nutrient interactions and loss states (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. 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