{"id":"611934e8-5dba-5019-8ede-b03f46eca583","stable_key":"0ad8610d-d575-5870-b7cd-763a9f750783:copper-steap2-reduces-copper","predicate":"reduces","statement":"Expressed mouse Steap2 reduced Cu(II) to Cu(I) and increased cellular copper uptake in the tested human cell system.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"83e09b0a-5180-5cc9-86af-3a6509d3808f","mechanism_event_label":"This enzyme prepares copper in a chemical form compatible with uptake.","subject":{"id":"2bde9d5c-d68e-519f-bc54-4ed5c40864ad","slug":"mouse-steap2","display_name":"Mouse metalloreductase Steap2","entity_type_key":"protein"},"object":{"id":"2a870bb5-05a0-5e51-a70c-a9a843a8b571","slug":"copper-ii","display_name":"Copper(II) ion","entity_type_key":"ion"},"evidence_count":1,"mechanism_event":{"id":"83e09b0a-5180-5cc9-86af-3a6509d3808f","stable_key":"0ad8610d-d575-5870-b7cd-763a9f750783:copper-steap2-reduces-copper-event","event_type":"biochemical_relationship","label":"This enzyme prepares copper in a chemical form compatible with uptake.","description":"Expressed mouse Steap2 reduced Cu(II) to Cu(I) and increased cellular copper uptake in the tested human cell system.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"162020b5-1fa5-526e-8405-452891245722","slug":"copper-i","display_name":"Copper(I) ion","entity_type_key":"ion"},"role":"reduction product","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"2bde9d5c-d68e-519f-bc54-4ed5c40864ad","slug":"mouse-steap2","display_name":"Mouse metalloreductase Steap2","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"2a870bb5-05a0-5e51-a70c-a9a843a8b571","slug":"copper-ii","display_name":"Copper(II) ion","entity_type_key":"ion"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/copper-research/16609065.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d0f42a3f30c22ba4235d82f21ba165c78b6c519a6218f487411fb2247ecc0d9f\", \"start_char\": 0, \"end_char\": 827, \"text_sha256\": \"d0f42a3f30c22ba4235d82f21ba165c78b6c519a6218f487411fb2247ecc0d9f\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Mouse Steap expression constructs and metal-reduction assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Transient expression of Steap2, Steap3 or Steap4","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Protein species verified in primary Methods (PMC1785011). Overexpression does not establish the dominant intestinal reductase in humans; relative activity can reflect localization and abundance.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Copper research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"copper","display_name":"Copper","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Mouse proteins expressed in human HEK293T cells","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"This enzyme prepares copper in a chemical form compatible with uptake.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[copper-p16609065] The Steap proteins are metalloreductases. (2006). https://pubmed.ncbi.nlm.nih.gov/16609065/ DOI: 10.1182/blood-2006-02-003681","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Cell surface and endosomal compartments","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"842dd27b-b030-5f89-a294-b68b382f1a86","evidence_kind":"source_excerpt","locator":"Lines 273-284","start_line":273,"end_line":284,"excerpt":"### copper-steap2-reduces-copper\nExpressed mouse Steap2 reduced Cu(II) to Cu(I) and increased cellular copper uptake in the tested human cell system.\nCondition category: normal\nnutrient_topic: Copper research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: This enzyme prepares copper in a chemical form compatible with uptake.\norganism: Mouse proteins expressed in human HEK293T cells\ntissue_or_cell_type: Cell surface and endosomal compartments\nexperimental_model: Mouse Steap expression constructs and metal-reduction assays\nlimitations: Protein species verified in primary Methods (PMC1785011). Overexpression does not establish the dominant intestinal reductase in humans; relative activity can reflect localization and abundance.\nexposure: Transient expression of Steap2, Steap3 or Steap4\nevidence_span: {\"source_cache\": \"artifacts/copper-research/16609065.abstract.txt\", \"locator\": \"Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"d0f42a3f30c22ba4235d82f21ba165c78b6c519a6218f487411fb2247ecc0d9f\", \"start_char\": 0, \"end_char\": 827, \"text_sha256\": \"d0f42a3f30c22ba4235d82f21ba165c78b6c519a6218f487411fb2247ecc0d9f\"}\n[copper-p16609065] The Steap proteins are metalloreductases. (2006). https://pubmed.ncbi.nlm.nih.gov/16609065/ DOI: 10.1182/blood-2006-02-003681","model_system":"Mouse Steap expression constructs and metal-reduction assays","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. 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