{"id":"c2561af1-2359-5011-a4ee-829bd44a66b4","stable_key":"e13b03e1-a614-543a-ac1b-97df18cfe30d:iron-iron-hepcidin-affinity","predicate":"enhances_hepcidin_binding_to","statement":"Iron increased hepcidin affinity for ferroportin approximately 80-fold in the measured binding system.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"7f652760-3668-5463-a6f3-f0d50337d548","mechanism_event_label":"The exporter’s metal-loading state changes how strongly the regulator binds.","subject":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"object":{"id":"2210be14-d81c-5a26-a3fb-5b566f47f1fd","slug":"slc40a1","display_name":"Ferroportin / SLC40A1","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"7f652760-3668-5463-a6f3-f0d50337d548","stable_key":"e13b03e1-a614-543a-ac1b-97df18cfe30d:iron-iron-hepcidin-affinity-event","event_type":"biochemical_relationship","label":"The exporter’s metal-loading state changes how strongly the regulator binds.","description":"Iron increased hepcidin affinity for ferroportin approximately 80-fold in the measured binding system.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"6d4be6b8-eba9-5d6b-93f9-4642b87f7b6f","slug":"hamp","display_name":"Hepcidin","entity_type_key":"protein"},"role":"regulatory_ligand","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"59d6d1cd-df32-5b58-b950-3188bc7b95d6","slug":"iron-ii","display_name":"Ferrous iron","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"2210be14-d81c-5a26-a3fb-5b566f47f1fd","slug":"slc40a1","display_name":"Ferroportin / SLC40A1","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/iron-research/32814342.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"8de67bc7ca2250cfab2f2cb71c2da16b4806c05cf5d4b6e648b191596b6e0da0\", \"start_char\": 0, \"end_char\": 1365, \"text_sha256\": \"8de67bc7ca2250cfab2f2cb71c2da16b4806c05cf5d4b6e648b191596b6e0da0\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Cryo-EM in lipid nanodiscs and binding/transport analysis","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Apo state, hepcidin and cobalt mimetic; iron-dependent affinity measurements","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Metal sites include a cobalt-bound structural preparation; the degradation-selectivity model is an interpretation, not proof that only loaded molecules are ever degraded.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Iron research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"iron","display_name":"Iron","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Human ferroportin","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The exporter’s metal-loading state changes how strongly the regulator binds.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[iron-p32814342] Structure of hepcidin-bound ferroportin reveals iron homeostatic mechanisms. (2020). https://pubmed.ncbi.nlm.nih.gov/32814342/ DOI: 10.1038/s41586-020-2668-z","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Purified membrane transporter","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"8307e07a-f4cd-57ce-b714-d3bffad82332","evidence_kind":"source_excerpt","locator":"Lines 758-769","start_line":758,"end_line":769,"excerpt":"### iron-iron-hepcidin-affinity\nIron increased hepcidin affinity for ferroportin approximately 80-fold in the measured binding system.\nCondition category: normal\nnutrient_topic: Iron research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The exporter’s metal-loading state changes how strongly the regulator binds.\norganism: Human ferroportin\ntissue_or_cell_type: Purified membrane transporter\nexperimental_model: Cryo-EM in lipid nanodiscs and binding/transport analysis\nlimitations: Metal sites include a cobalt-bound structural preparation; the degradation-selectivity model is an interpretation, not proof that only loaded molecules are ever degraded.\nexposure: Apo state, hepcidin and cobalt mimetic; iron-dependent affinity measurements\nevidence_span: {\"source_cache\": \"artifacts/iron-research/32814342.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"8de67bc7ca2250cfab2f2cb71c2da16b4806c05cf5d4b6e648b191596b6e0da0\", \"start_char\": 0, \"end_char\": 1365, \"text_sha256\": \"8de67bc7ca2250cfab2f2cb71c2da16b4806c05cf5d4b6e648b191596b6e0da0\"}\n[iron-p32814342] Structure of hepcidin-bound ferroportin reveals iron homeostatic mechanisms. 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