{"id":"9c8b05cb-8114-5c2b-b896-9fb5bc6ba2fe","stable_key":"1deb434a-3547-51a0-a038-87b1ce79ec38:vdm-low-phosphate-adaptation-persists-without-vdr","predicate":"permits_residual_adaptation","statement":"A low-phosphate diet increased intestinal NaPi-IIb protein expression even in Vdr-null mice.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"cbcbd2a7-f4f2-5a04-a5d8-0d8c13104d27","mechanism_event_label":"The intestine retained a phosphate-conservation response despite loss of vitamin D receptor signaling.","subject":{"id":"9a2fec47-9a2f-503a-8dd5-6eaea24fba81","slug":"mouse-vdr-null-genotype","display_name":"Vdr-null mouse genotype","entity_type_key":"gene"},"object":{"id":"53d782cc-66b4-510e-b9e2-b58c51bde3cd","slug":"slc34a2","display_name":"Sodium-phosphate cotransporter NaPi-IIb / SLC34A2","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"cbcbd2a7-f4f2-5a04-a5d8-0d8c13104d27","stable_key":"1deb434a-3547-51a0-a038-87b1ce79ec38:vdm-low-phosphate-adaptation-persists-without-vdr-event","event_type":"biochemical_relationship","label":"The intestine retained a phosphate-conservation response despite loss of vitamin D receptor signaling.","description":"A low-phosphate diet increased intestinal NaPi-IIb protein expression even in Vdr-null mice.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"9a2fec47-9a2f-503a-8dd5-6eaea24fba81","slug":"mouse-vdr-null-genotype","display_name":"Vdr-null mouse genotype","entity_type_key":"gene"},"role":"genetic-perturbation","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d725020b-bacc-5e90-b370-cda246025c91","slug":"vdr","display_name":"Vitamin D receptor / VDR","entity_type_key":"protein"},"role":"missing-receptor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"53d782cc-66b4-510e-b9e2-b58c51bde3cd","slug":"slc34a2","display_name":"Sodium-phosphate cotransporter NaPi-IIb / SLC34A2","entity_type_key":"protein"},"role":"regulated-transporter","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"b28dfc54-a5ef-5f9e-ac1f-890b68e58dc3","slug":"inorganic-phosphate","display_name":"Inorganic phosphate","entity_type_key":"chemical_species"},"role":"restricted-nutrient","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"Vitamin D–calcium–phosphate regulation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_locator","value_text":"Abstract: reported experimental results","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_scope","value_text":"D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Vdr-null and wild-type mice; intestinal brush-border transporter immunodetection","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Vdr deletion plus dietary phosphate restriction; exact dietary percentage and duration not given in the retrieved abstract.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Baseline NaPi-IIb protein and sodium-dependent phosphate transport were lower in knockout mice; preserved adaptation does not imply normal baseline transport.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient","value_text":"Vitamin D2 and D3","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-d","display_name":"Vitamin D2 and D3","entity_type_key":"chemical_species"}},{"dimension":"nutrient_topic","value_text":"Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-d","display_name":"Vitamin D2 and D3","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Mus musculus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The intestine retained a phosphate-conservation response despite loss of vitamin D receptor signaling.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[vdm-segawa2004] Intestinal Na-P(i) cotransporter adaptation to dietary P(i) content in vitamin D receptor null mice. (2004). https://pubmed.ncbi.nlm.nih.gov/14996670/ DOI: 10.1152/ajprenal.00375.2003","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Intestinal brush-border membrane","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"64aa16a6-122e-5d11-8b1f-e3628f5e3449","evidence_kind":"source_excerpt","locator":"Lines 713-727","start_line":713,"end_line":727,"excerpt":"### vdm-low-phosphate-adaptation-persists-without-vdr\nA low-phosphate diet increased intestinal NaPi-IIb protein expression even in Vdr-null mice.\nCondition category: machinery_impairment\nnutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The intestine retained a phosphate-conservation response despite loss of vitamin D receptor signaling.\norganism: Mus musculus\ntissue_or_cell_type: Intestinal brush-border membrane\nexperimental_model: Vdr-null and wild-type mice; intestinal brush-border transporter immunodetection\nlimitations: Baseline NaPi-IIb protein and sodium-dependent phosphate transport were lower in knockout mice; preserved adaptation does not imply normal baseline transport.\nexposure: Vdr deletion plus dietary phosphate restriction; exact dietary percentage and duration not given in the retrieved abstract.\ncross_nutrient: Vitamin D–calcium–phosphate regulation.\nevidence_locator: Abstract: reported experimental results\nnutrient: Vitamin D2 and D3\nevidence_scope: D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison.\n[vdm-segawa2004] Intestinal Na-P(i) cotransporter adaptation to dietary P(i) content in vitamin D receptor null mice. 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