{"id":"57f1c10d-893c-5c16-bcf9-e61182d2662d","stable_key":"5102beb6-9f61-500e-af10-9ac63649e0b7:k-free-diet-increases-nbce1a","predicate":"deprivation-increases","statement":"Four days of potassium-free diet increased cortical proximal-tubule NBCe1-A expression in wild-type mice.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"811750ec-9ca6-5ffb-ad68-e6d2515a5bad","mechanism_event_label":"A sodium-bicarbonate transporter adapted during potassium conservation.","subject":{"id":"87435e1d-e1cd-57da-984b-203b2f5f29a4","slug":"potassium","display_name":"Potassium","entity_type_key":"nutrient_element"},"object":{"id":"0c3570c2-1a53-57ec-8e62-660be066da31","slug":"slc4a4-nbce1-a","display_name":"NBCe1-A splice variant","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"811750ec-9ca6-5ffb-ad68-e6d2515a5bad","stable_key":"5102beb6-9f61-500e-af10-9ac63649e0b7:k-free-diet-increases-nbce1a-event","event_type":"biochemical_relationship","label":"A sodium-bicarbonate transporter adapted during potassium conservation.","description":"Four days of potassium-free diet increased cortical proximal-tubule NBCe1-A expression in wild-type mice.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"87435e1d-e1cd-57da-984b-203b2f5f29a4","slug":"potassium","display_name":"Potassium","entity_type_key":"nutrient_element"},"role":"upstream","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"0c3570c2-1a53-57ec-8e62-660be066da31","slug":"slc4a4-nbce1-a","display_name":"NBCe1-A splice variant","entity_type_key":"protein"},"role":"downstream","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"38de8704-84db-5770-ac1d-242cd787e798","slug":"sodium-ion","display_name":"Sodium ion","entity_type_key":"ion"},"role":"cotransported-ion","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"edf44f6b-7b23-5b97-a86b-c940e5812b06","slug":"bicarbonate-ion","display_name":"Bicarbonate ion","entity_type_key":"ion"},"role":"transported-ion","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"Potassium deprivation regulates sodium-bicarbonate transport machinery.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"endpoint","value_text":"Four days of potassium-free diet increased cortical proximal-tubule NBCe1-A expression in wild-type mice.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental-exposure","value_text":"NBCe1-A-selective knockout mice and wild-type littermates on control or potassium-free diets; four-day response.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"NBCe1-A-selective knockout mice and wild-type littermates on control or potassium-free diets; four-day response.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Expression was measured; this record does not assign a bicarbonate transport stoichiometry or measure its flux.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Potassium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"potassium","display_name":"Potassium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Mus musculus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A sodium-bicarbonate transporter adapted during potassium conservation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[lee-2020-nbce1a] NBCe1-A is required for the renal ammonia and K+ response to hypokalemia (2020). https://pubmed.ncbi.nlm.nih.gov/31841393/ DOI: 10.1152/ajprenal.00481.2019","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"cortical proximal tubule","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"71f2b123-9ef4-560b-9641-51863af0f817","evidence_kind":"source_excerpt","locator":"Lines 1068-1080","start_line":1068,"end_line":1080,"excerpt":"### k-free-diet-increases-nbce1a\nFour days of potassium-free diet increased cortical proximal-tubule NBCe1-A expression in wild-type mice.\nCondition category: nutrient_deficiency\nnutrient_topic: Potassium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A sodium-bicarbonate transporter adapted during potassium conservation.\norganism: Mus musculus\ntissue_or_cell_type: cortical proximal tubule\nexperimental_model: NBCe1-A-selective knockout mice and wild-type littermates on control or potassium-free diets; four-day response.\nlimitations: Expression was measured; this record does not assign a bicarbonate transport stoichiometry or measure its flux.\ncross_nutrient: Potassium deprivation regulates sodium-bicarbonate transport machinery.\nexperimental-exposure: NBCe1-A-selective knockout mice and wild-type littermates on control or potassium-free diets; four-day response.\nendpoint: Four days of potassium-free diet increased cortical proximal-tubule NBCe1-A expression in wild-type mice.\n[lee-2020-nbce1a] NBCe1-A is required for the renal ammonia and K+ response to hypokalemia (2020). https://pubmed.ncbi.nlm.nih.gov/31841393/ DOI: 10.1152/ajprenal.00481.2019","model_system":"NBCe1-A-selective knockout mice and wild-type littermates on control or potassium-free diets; four-day response.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [lee-2020-nbce1a] NBCe1-A is required for the renal ammonia and K+ response to hypokalemia (2020). https://pubmed.ncbi.nlm.nih.gov/31841393/ DOI: 10.1152/ajprenal.00481.2019","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"241226ee-6b7d-5cc7-9781-e6beb8ee1982","stable_key":"import-5102beb6-9f61-500e-af10-9ac63649e0b7","title":"Potassium: cross-nutrient mechanisms and 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":"a8f89f8d84b48c0f93048dfc45f7f57a67dd9a7249968a096a14aeb03d8b7a52","revision_id":"de4ec6f4-58a1-537b-8169-97b783898df1","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}