{"id":"8eb9e985-7f14-5b43-a8ca-43d87c3b6c55","stable_key":"41a89233-da9a-5b7b-9c18-e19bbadcfe2d:methionine-toxicant-mimicry","predicate":"uses_shared_transport","statement":"Methylmercury-L-cysteine used human LAT1/LAT2 in oocyte assays, with substrate exchange characteristics resembling methionine.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"42d4a251-9eb5-52a7-ac6e-34bdb88b6bf2","mechanism_event_label":"A toxicant complex can exploit nutrient transport machinery.","subject":{"id":"a04b6ad4-659f-5f5c-958f-a0a5861b9cb6","slug":"methylmercury-l-cysteine","display_name":"Methylmercury-L-cysteine complex","entity_type_key":"small_molecule"},"object":{"id":"d5a09940-7388-56d3-bbaa-47bf67d684d0","slug":"human-lat1-lat2-substrate-transport","display_name":"Substrate transport through human LAT1/LAT2","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"42d4a251-9eb5-52a7-ac6e-34bdb88b6bf2","stable_key":"41a89233-da9a-5b7b-9c18-e19bbadcfe2d:methionine-toxicant-mimicry-event","event_type":"observed_relationship","label":"A toxicant complex can exploit nutrient transport machinery.","description":"Methylmercury-L-cysteine used human LAT1/LAT2 in oocyte assays, with substrate exchange characteristics resembling methionine.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"a04b6ad4-659f-5f5c-958f-a0a5861b9cb6","slug":"methylmercury-l-cysteine","display_name":"Methylmercury-L-cysteine complex","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"d5a09940-7388-56d3-bbaa-47bf67d684d0","slug":"human-lat1-lat2-substrate-transport","display_name":"Substrate transport through human LAT1/LAT2","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9d39f561-740b-5f67-bba7-8a72ef612a99","slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"16d078ff-692c-50eb-a34b-c61ef43821e1","slug":"slc7a5","display_name":"Human L-type amino acid transporter 1 / LAT1 / SLC7A5","entity_type_key":"protein"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"02373ade-38d4-50e0-b74d-f7e9ab0e3846","slug":"slc7a8","display_name":"Human L-type amino acid transporter 2 / LAT2 / SLC7A8","entity_type_key":"protein"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"ca899f13-50ad-55e5-ab99-329ae0038c74","slug":"l-cysteine","display_name":"L-Cysteine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human carrier expression in Xenopus oocytes.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Complex identity and chirality matter; this does not demonstrate protection from methionine supplementation.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Methionine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"methionine","display_name":"L-Methionine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A toxicant complex can exploit nutrient transport machinery.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Transport of a neurotoxicant by molecular mimicry: the methylmercury-L-cysteine complex is a substrate for human L-type large neutral amino acid transporter (LAT) 1 and LAT2. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12117417/ · DOI 10.1042/BJ20020841","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f43e01cb-16e5-5957-8496-cc19b466f3ee","evidence_kind":"source_excerpt","locator":"Lines 36-42","start_line":36,"end_line":42,"excerpt":"## methionine-toxicant-mimicry\nA toxicant complex can exploit nutrient transport machinery.\nMethylmercury-L-cysteine used human LAT1/LAT2 in oocyte assays, with substrate exchange characteristics resembling methionine.\nModel: Human carrier expression in Xenopus oocytes.\nLimitations: Complex identity and chirality matter; this does not demonstrate protection from methionine supplementation.\nEvidence access: Primary abstract\nTransport of a neurotoxicant by molecular mimicry: the methylmercury-L-cysteine complex is a substrate for human L-type large neutral amino acid transporter (LAT) 1 and LAT2. · 2002 · https://pubmed.ncbi.nlm.nih.gov/12117417/ · DOI 10.1042/BJ20020841","model_system":"Human carrier expression in Xenopus oocytes.","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":"d969b004-ccc2-5bb4-9109-8ac649137ad1","stable_key":"import-41a89233-da9a-5b7b-9c18-e19bbadcfe2d","title":"L-Methionine: transport, methylation, sulfur metabolism 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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