{"id":"71efe7a2-1c75-5851-af55-fc982cdb8b0f","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:va-rbp1-couples-stra6","predicate":"enhances","statement":"Cellular RBP1 enhanced STRA6-mediated uptake of RBP-bound retinol.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"2c878e59-be68-5518-a4bb-cb6363cc1807","mechanism_event_label":"An intracellular retinol-binding protein helps retain delivered vitamin A.","subject":{"id":"e7f2697b-3ad8-5f52-849b-48cc0f1e9019","slug":"rbp1","display_name":"Cellular retinol-binding protein 1 / RBP1","entity_type_key":"protein"},"object":{"id":"33db7555-8a5e-5dbd-a32b-ff87bd24cd5d","slug":"stra6-retinol-uptake","display_name":"STRA6-mediated retinol uptake","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"2c878e59-be68-5518-a4bb-cb6363cc1807","stable_key":"dff9f743-3766-5f20-a71e-d6d2bd5bfb6f:va-rbp1-couples-stra6-event","event_type":"biochemical_relationship","label":"An intracellular retinol-binding protein helps retain delivered vitamin A.","description":"Cellular RBP1 enhanced STRA6-mediated uptake of RBP-bound retinol.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"dae8de03-841b-57f1-8fbd-9b20401a80d1","slug":"stra6","display_name":"Retinol uptake receptor STRA6","entity_type_key":"protein"},"role":"receptor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"fa1220a6-1bfb-5a15-b57f-65e5d2135b19","slug":"holo-rbp4","display_name":"Retinol-loaded RBP4","entity_type_key":"protein_state"},"role":"donor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"e7f2697b-3ad8-5f52-849b-48cc0f1e9019","slug":"rbp1","display_name":"Cellular retinol-binding protein 1 / RBP1","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"33db7555-8a5e-5dbd-a32b-ff87bd24cd5d","slug":"stra6-retinol-uptake","display_name":"STRA6-mediated retinol uptake","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"evidence_location","value_text":"Figure 1","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Transfected-cell radioretinol uptake and real-time retinol-release assays.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"STRA6 plus CRBP-I compared with STRA6 alone.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Coupling is supported, but absolute RBP1 dependence is not. Cell-line species were not resolved in the retrieved abstract/figure evidence; no species-specific extension is asserted.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin A research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-a","display_name":"Vitamin A","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Mammalian transfected cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"outcome","value_text":"Cellular RBP1 enhanced STRA6-mediated uptake of RBP-bound retinol.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"An intracellular retinol-binding protein helps retain delivered vitamin A.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[va-kawaguchi-2011] Receptor-mediated cellular uptake mechanism that couples to intracellular storage (2011). https://pmc.ncbi.nlm.nih.gov/articles/PMC3199320/ DOI: 10.1021/cb200178w","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Plasma membrane and cytoplasm","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"52aaaff2-55a8-5612-be33-7418a924633c","evidence_kind":"source_excerpt","locator":"Lines 473-485","start_line":473,"end_line":485,"excerpt":"### va-rbp1-couples-stra6\nCellular RBP1 enhanced STRA6-mediated uptake of RBP-bound retinol.\nCondition category: normal\nnutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: An intracellular retinol-binding protein helps retain delivered vitamin A.\norganism: Mammalian transfected cells\ntissue_or_cell_type: Plasma membrane and cytoplasm\nexperimental_model: Transfected-cell radioretinol uptake and real-time retinol-release assays.\nlimitations: Coupling is supported, but absolute RBP1 dependence is not. Cell-line species were not resolved in the retrieved abstract/figure evidence; no species-specific extension is asserted.\nexposure: STRA6 plus CRBP-I compared with STRA6 alone.\noutcome: Cellular RBP1 enhanced STRA6-mediated uptake of RBP-bound retinol.\nevidence_location: Figure 1\n[va-kawaguchi-2011] Receptor-mediated cellular uptake mechanism that couples to intracellular storage (2011). https://pmc.ncbi.nlm.nih.gov/articles/PMC3199320/ DOI: 10.1021/cb200178w","model_system":"Transfected-cell radioretinol uptake and real-time retinol-release assays.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. 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