{"id":"4d1ae7ff-35a2-5f8b-a2c7-7acd87268591","stable_key":"3279ff78-2460-5064-bfc0-3f2987af85a0:melatonin-mt2-gi-structure","predicate":"couples_to","statement":"Agonist-bound human MT2 was structurally resolved in a Gi signaling complex.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"e2e8972b-c069-53d7-9378-ff5cfa03eb26","mechanism_event_label":"The receptor and its signaling partner are separate searchable components.","subject":{"id":"3c2136fb-a2de-5f3b-bcb9-53d037b6e1fc","slug":"mtnr1b","display_name":"Human melatonin receptor 1B / MT2 / MTNR1B","entity_type_key":"protein"},"object":{"id":"1e3e31bf-b208-5d55-a42f-9a61fb1146eb","slug":"gi-heterotrimer","display_name":"Inhibitory heterotrimeric G protein / Gi, assay-specified subunits","entity_type_key":"protein_family"},"evidence_count":1,"mechanism_event":{"id":"e2e8972b-c069-53d7-9378-ff5cfa03eb26","stable_key":"3279ff78-2460-5064-bfc0-3f2987af85a0:melatonin-mt2-gi-structure-event","event_type":"biochemical_relationship","label":"The receptor and its signaling partner are separate searchable components.","description":"Agonist-bound human MT2 was structurally resolved in a Gi signaling complex.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"5823c263-2861-59e3-8caf-055263c3b932","slug":"ramelteon","display_name":"Ramelteon","entity_type_key":"small_molecule"},"role":"structural_agonist","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"3c2136fb-a2de-5f3b-bcb9-53d037b6e1fc","slug":"mtnr1b","display_name":"Human melatonin receptor 1B / MT2 / MTNR1B","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"1e3e31bf-b208-5d55-a42f-9a61fb1146eb","slug":"gi-heterotrimer","display_name":"Inhibitory heterotrimeric G protein / Gi, assay-specified subunits","entity_type_key":"protein_family"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/melatonin-research/35075127.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"08af0c72228d7c72723f238e83eeabef1ca9196833c7e385ed0c75577c97024b\", \"start_char\": 0, \"end_char\": 1239, \"text_sha256\": \"08af0c72228d7c72723f238e83eeabef1ca9196833c7e385ed0c75577c97024b\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Cryo-EM structures and functional receptor assays","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"2-iodomelatonin/ramelteon for MT1; ramelteon for MT2","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Structures used agonists, not native melatonin in every complex. Receptor structure does not itself prove clinical effects or subtype-selective supplement actions.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Melatonin research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"melatonin","display_name":"Melatonin","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Human MT1 and MT2 signaling complexes","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The receptor and its signaling partner are separate searchable components.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[melatonin-p35075127] Structural basis of the ligand binding and signaling mechanism of melatonin receptors. (2022). https://pubmed.ncbi.nlm.nih.gov/35075127/ DOI: 10.1038/s41467-022-28111-3","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Agonist-bound receptor-Gi coupling","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"461fe7c3-864b-54a5-84fa-3072565e613f","evidence_kind":"source_excerpt","locator":"Lines 409-420","start_line":409,"end_line":420,"excerpt":"### melatonin-mt2-gi-structure\nAgonist-bound human MT2 was structurally resolved in a Gi signaling complex.\nCondition category: normal\nnutrient_topic: Melatonin research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The receptor and its signaling partner are separate searchable components.\norganism: Human MT1 and MT2 signaling complexes\ntissue_or_cell_type: Agonist-bound receptor-Gi coupling\nexperimental_model: Cryo-EM structures and functional receptor assays\nlimitations: Structures used agonists, not native melatonin in every complex. Receptor structure does not itself prove clinical effects or subtype-selective supplement actions.\nexposure: 2-iodomelatonin/ramelteon for MT1; ramelteon for MT2\nevidence_span: {\"source_cache\": \"artifacts/melatonin-research/35075127.abstract.txt\", \"locator\": \"Primary indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"08af0c72228d7c72723f238e83eeabef1ca9196833c7e385ed0c75577c97024b\", \"start_char\": 0, \"end_char\": 1239, \"text_sha256\": \"08af0c72228d7c72723f238e83eeabef1ca9196833c7e385ed0c75577c97024b\"}\n[melatonin-p35075127] Structural basis of the ligand binding and signaling mechanism of melatonin receptors. (2022). https://pubmed.ncbi.nlm.nih.gov/35075127/ DOI: 10.1038/s41467-022-28111-3","model_system":"Cryo-EM structures and functional receptor assays","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [melatonin-p35075127] Structural basis of the ligand binding and signaling mechanism of melatonin receptors. (2022). https://pubmed.ncbi.nlm.nih.gov/35075127/ DOI: 10.1038/s41467-022-28111-3","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"bab588de-d217-5038-9c8b-b41222eba08b","stable_key":"import-3279ff78-2460-5064-bfc0-3f2987af85a0","title":"Melatonin: synthesis, receptors, circadian timing 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":"ff4f279d263f95a69da8e7e8a6c6318ab6ba1b55254dbbda1bfa9ce437e1db80","revision_id":"0318eef8-ff38-513e-8ffa-458146ca5e77","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}