{"id":"daef5061-62be-5646-82c0-d0cc41350bab","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:ca-itpr3-er-calcium-channel","predicate":"transports","statement":"Human ITPR3 forms a calcium-release channel with an open pore in the IP3/ATP/Ca2+-bound structural state.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"3f5cdd05-f2f5-53da-aefc-0bfcb314b28b","mechanism_event_label":"ITPR3 provides a route for calcium to leave the ER.","subject":{"id":"a9ba94eb-da8a-5bdb-b087-36571977c52b","slug":"itpr3","display_name":"Inositol 1,4,5-trisphosphate receptor type 3 / ITPR3","entity_type_key":"protein"},"object":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"evidence_count":1,"mechanism_event":{"id":"3f5cdd05-f2f5-53da-aefc-0bfcb314b28b","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:ca-itpr3-er-calcium-channel-event","event_type":"transport","label":"ITPR3 provides a route for calcium to leave the ER.","description":"Human ITPR3 forms a calcium-release channel with an open pore in the IP3/ATP/Ca2+-bound structural state.","status":"provisional","compartment":{"slug":"er-membrane","display_name":"ER membrane"},"participants":[{"entity":{"id":"a9ba94eb-da8a-5bdb-b087-36571977c52b","slug":"itpr3","display_name":"Inositol 1,4,5-trisphosphate receptor type 3 / ITPR3","entity_type_key":"protein"},"role":"channel","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"role":"transported_substrate","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"7005bbc2-d4b5-5903-b776-94dd2288d35f","slug":"ip3","display_name":"IP3","entity_type_key":"small_molecule"},"role":"activator","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"role":"allosteric_modulator","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"7df03d06-a2b7-524a-aa99-c9cf6a3bf4c2","slug":"er-membrane","display_name":"ER membrane","entity_type_key":"organelle"},"role":"experimental_location","stoichiometry":null,"state_label":"","sequence_order":4,"notes":"Study location; presence here is not a separate transport or causal claim."}]},"contexts":[{"dimension":"compartment_description","value_text":"ER membrane","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Recombinant human ITPR3; cryo-EM in ligand-bound gating states","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Structure specifies ITPR3; it must not be relabeled as ITPR1 or a measurement of every receptor subtype.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Calcium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"calcium","display_name":"Calcium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"ITPR3 provides a route for calcium to leave the ER.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[ca-schmitz2022] Structural basis for activation and gating of IP3 receptors (2022). https://pubmed.ncbi.nlm.nih.gov/35301323/ DOI: 10.1038/s41467-022-29073-2","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"research_relationship_category","value_text":"transport","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Recombinant ITPR3","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"transport_effect","value_text":"raises","comparator":null,"unit":null,"notes":"A calcium-release channel: the recorded direction is ER lumen to cytosol.","entity":null},{"dimension":"transport_or_reaction_direction","value_text":"ER lumen to cytosol","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"transport_pool","value_text":"cytosolic calcium","comparator":null,"unit":null,"notes":"A calcium-release channel: the recorded direction is ER lumen to cytosol.","entity":null}],"evidence":[{"id":"e800d95e-b365-52d4-be73-8bf65872215f","evidence_kind":"source_excerpt","locator":"Lines 478-490","start_line":478,"end_line":490,"excerpt":"### ca-itpr3-er-calcium-channel\nHuman ITPR3 forms a calcium-release channel with an open pore in the IP3/ATP/Ca2+-bound structural state.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: ITPR3 provides a route for calcium to leave the ER.\norganism: Homo sapiens\ntissue_or_cell_type: Recombinant ITPR3\nexperimental_model: Recombinant human ITPR3; cryo-EM in ligand-bound gating states\nlimitations: Structure specifies ITPR3; it must not be relabeled as ITPR1 or a measurement of every receptor subtype.\nresearch_relationship_category: transport\ntransport_or_reaction_direction: ER lumen to cytosol\ncompartment_description: ER membrane\n[ca-schmitz2022] Structural basis for activation and gating of IP3 receptors (2022). https://pubmed.ncbi.nlm.nih.gov/35301323/ DOI: 10.1038/s41467-022-29073-2","model_system":"Recombinant human ITPR3; cryo-EM in ligand-bound gating states","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [ca-schmitz2022] Structural basis for activation and gating of IP3 receptors (2022). https://pubmed.ncbi.nlm.nih.gov/35301323/ DOI: 10.1038/s41467-022-29073-2","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"3c083fa0-59c6-50e9-af42-678d0e3c1006","stable_key":"import-434e1e27-eb90-583a-956b-62472726ffba","title":"Calcium: mechanism-first literature curation (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":"965c934d6b147f2b62f8d45ce6d7a87681a600bfe5c46a585b4704889afd3fc1","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}