{"id":"bd03220d-8752-5986-9e2c-faf7475ac031","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-casr-loss","predicate":"is_required_for","statement":"CaSR knockout abolished the phenylalanine-evoked calcium response in primary mouse I cells and prevented the normal stimulatory CCK response; responses to KCl and tryptone were preserved.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"193c54e5-17f0-5a58-99eb-3f8dfa6bbc86","mechanism_event_label":"Removing one sensor disables that route without disabling every secretion trigger.","subject":{"id":"18071fe3-a86f-5dac-b440-1e2e59d22f24","slug":"mouse-casr","display_name":"Mouse calcium-sensing receptor / Casr","entity_type_key":"protein"},"object":{"id":"b9a33255-4b95-5668-b2e9-daf129f66f1a","slug":"mouse-icell-cck-secretion","display_name":"Mouse primary intestinal I-cell CCK secretion","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"193c54e5-17f0-5a58-99eb-3f8dfa6bbc86","stable_key":"56f1d914-e7da-595a-af69-c217b2b47407:l-phenylalanine-casr-loss-event","event_type":"observed_relationship","label":"Removing one sensor disables that route without disabling every secretion trigger.","description":"CaSR knockout abolished the phenylalanine-evoked calcium response in primary mouse I cells and prevented the normal stimulatory CCK response; responses to KCl and tryptone were preserved.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"18071fe3-a86f-5dac-b440-1e2e59d22f24","slug":"mouse-casr","display_name":"Mouse calcium-sensing receptor / Casr","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b9a33255-4b95-5668-b2e9-daf129f66f1a","slug":"mouse-icell-cck-secretion","display_name":"Mouse primary intestinal I-cell CCK secretion","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"190407ad-0219-54b5-b05f-7c75f3895ca6","slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"role":"context_participant","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":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"CaSR-null compared with wild-type primary mouse intestinal I cells.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This is receptor failure, not phenylalanine or calcium dietary deficiency.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Phenylalanine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-phenylalanine","display_name":"L-Phenylalanine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Removing one sensor disables that route without disabling every secretion trigger.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"The extracellular calcium-sensing receptor is required for cholecystokinin secretion in response to L-phenylalanine in acutely isolated intestinal I cells. · 2011 · https://pubmed.ncbi.nlm.nih.gov/21252045/ · DOI 10.1152/ajpgi.00342.2010","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":"71ccb39d-188a-54ef-ab84-f362325faec3","evidence_kind":"source_excerpt","locator":"Lines 286-292","start_line":286,"end_line":292,"excerpt":"## l-phenylalanine-casr-loss\nRemoving one sensor disables that route without disabling every secretion trigger.\nCaSR knockout abolished the phenylalanine-evoked calcium response in primary mouse I cells and prevented the normal stimulatory CCK response; responses to KCl and tryptone were preserved.\nModel: CaSR-null compared with wild-type primary mouse intestinal I cells.\nLimitations: This is receptor failure, not phenylalanine or calcium dietary deficiency.\nEvidence access: Primary abstract\nThe extracellular calcium-sensing receptor is required for cholecystokinin secretion in response to L-phenylalanine in acutely isolated intestinal I cells. · 2011 · https://pubmed.ncbi.nlm.nih.gov/21252045/ · DOI 10.1152/ajpgi.00342.2010","model_system":"CaSR-null compared with wild-type primary mouse intestinal I cells.","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":"54de7c56-1e60-5d7b-8ef9-852c58ae92ba","stable_key":"import-56f1d914-e7da-595a-af69-c217b2b47407","title":"L-Phenylalanine: transport, protein synthesis, cofactor recycling and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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