{"id":"a50909b6-df3c-5fa0-915c-5b6f56552eb6","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-kir-block","predicate":"voltage_dependently_blocks","statement":"Cytoplasmic spermidine caused reversible voltage-dependent rectification of cloned HRK1 channels.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"fb7f3397-a66e-524c-9f97-aee87bb00d11","mechanism_event_label":"Spermidine can limit outward potassium current.","subject":{"id":"7014993c-468f-5c6b-ab04-80c87f9dfd9f","slug":"spermidine","display_name":"Spermidine","entity_type_key":"small_molecule"},"object":{"id":"23f993e0-3348-5205-b71f-1bb38b4fa4ff","slug":"hrk1-channel-assay","display_name":"HRK1 inward-rectifier potassium channel in the cloned-channel assay","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"fb7f3397-a66e-524c-9f97-aee87bb00d11","stable_key":"88eb7407-f147-558b-889b-0c89c4e0aa4a:spermidine-kir-block-event","event_type":"observed_relationship","label":"Spermidine can limit outward potassium current.","description":"Cytoplasmic spermidine caused reversible voltage-dependent rectification of cloned HRK1 channels.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"7014993c-468f-5c6b-ab04-80c87f9dfd9f","slug":"spermidine","display_name":"Spermidine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"23f993e0-3348-5205-b71f-1bb38b4fa4ff","slug":"hrk1-channel-assay","display_name":"HRK1 inward-rectifier potassium channel in the cloned-channel assay","entity_type_key":"protein"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"5dd31e52-f51e-51f3-880e-240abcc0ab1d","slug":"potassium-ion","display_name":"Potassium ion","entity_type_key":"ion"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Xenopus oocyte inside-out patches; construct species unresolved in accessed abstract.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Do not relabel the channel as a verified human isoform or infer a serum-potassium effect.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Spermidine collection; molecular form, preparation, species, exposure and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"spermidine","display_name":"Spermidine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"Spermidine can limit outward potassium current.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"The mechanism of inward rectification of potassium channels: \"long-pore plugging\" by cytoplasmic polyamines. · 1995 · https://pubmed.ncbi.nlm.nih.gov/8648298/ · DOI 10.1085/jgp.106.5.923","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"96fff83b-42cf-5429-a537-c4c08653c3b7","evidence_kind":"source_excerpt","locator":"Lines 430-436","start_line":430,"end_line":436,"excerpt":"## spermidine-kir-block\nSpermidine can limit outward potassium current.\nCytoplasmic spermidine caused reversible voltage-dependent rectification of cloned HRK1 channels.\nModel: Xenopus oocyte inside-out patches; construct species unresolved in accessed abstract.\nLimitations: Do not relabel the channel as a verified human isoform or infer a serum-potassium effect.\nEvidence access: Primary abstract\nThe mechanism of inward rectification of potassium channels: \"long-pore plugging\" by cytoplasmic polyamines. · 1995 · https://pubmed.ncbi.nlm.nih.gov/8648298/ · DOI 10.1085/jgp.106.5.923","model_system":"Xenopus oocyte inside-out patches; construct species unresolved in accessed abstract.","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":"4348f3f8-0180-58a3-b61c-55d03bb322d2","stable_key":"import-88eb7407-f147-558b-889b-0c89c4e0aa4a","title":"Spermidine: biosynthesis, hypusination, transport 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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