{"id":"42e7b56b-bc4b-599b-907a-07d0370c211d","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abcd4-n141k-transport","predicate":"impairs-transport-of","statement":"Purified human ABCD4 N141K lost detectable cobalamin transport in liposomes, despite ATPase activity comparable with wild type.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"f61cc50c-85a2-5606-a304-40fbdc06eefc","mechanism_event_label":"The variant disrupted B12 movement across the membrane.","subject":{"id":"8d866d53-6952-5300-afeb-be693c4d0ce4","slug":"abcd4-n141k","display_name":"Human ABCD4 N141K","entity_type_key":"protein_state"},"object":{"id":"b6d9b937-895d-5e0a-8cc5-0454a0b7d373","slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"},"evidence_count":1,"mechanism_event":{"id":"f61cc50c-85a2-5606-a304-40fbdc06eefc","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-abcd4-n141k-transport-event","event_type":"biochemical_relationship","label":"The variant disrupted B12 movement across the membrane.","description":"Purified human ABCD4 N141K lost detectable cobalamin transport in liposomes, despite ATPase activity comparable with wild type.","status":"provisional","compartment":{"slug":"lysosome","display_name":"Lysosome"},"participants":[{"entity":{"id":"831afa98-dacd-516d-ae1e-680432a78525","slug":"abcd4","display_name":"Human ABCD4 lysosomal cobalamin transporter","entity_type_key":"protein"},"role":"wild-type comparator","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"role":"ATPase substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"8d866d53-6952-5300-afeb-be693c4d0ce4","slug":"abcd4-n141k","display_name":"Human ABCD4 N141K","entity_type_key":"protein_state"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"b6d9b937-895d-5e0a-8cc5-0454a0b7d373","slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"machinery_impairment","comparator":null,"unit":null,"notes":"Imported condition classification; 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Study references: [kitai-2021-abcd4-transport] The lysosomal protein ABCD4 can transport vitamin B12 across liposomal membranes in vitro (2021). https://pubmed.ncbi.nlm.nih.gov/33845046/ DOI: 10.1016/j.jbc.2021.100654","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"73145023-2982-5848-aff2-8d8875d6b9c5","stable_key":"import-7fc92b9e-9cbf-556e-8719-6b5244625250","title":"Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"ad5b3a51d36e856aa7fdfd1cc23f690b094689bad87d28e1a621a54675a01c92","revision_id":"118bd616-0c13-549f-bfeb-bc439715b89c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}