{"id":"813e499f-7d7d-544e-8ede-16b68ab6a475","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:ca-micu12-calcium-sensing","predicate":"regulates","statement":"Calcium-responsive EF hands in MICU1 and MICU2 allow the uniporter to pass from restrained low-calcium uptake to uptake above a threshold.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"906f3e1f-afbd-5ca1-9673-c96fc397a9ae","mechanism_event_label":"MICU1 and MICU2 help the uniporter distinguish small calcium levels from a signal.","subject":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"object":{"id":"200eff80-420c-52f8-a4c5-4f5188b7b78b","slug":"mitochondrial-calcium-uniporter-complex","display_name":"Mitochondrial calcium uniporter complex","entity_type_key":"protein_complex"},"evidence_count":1,"mechanism_event":{"id":"906f3e1f-afbd-5ca1-9673-c96fc397a9ae","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:ca-micu12-calcium-sensing-event","event_type":"regulation","label":"MICU1 and MICU2 help the uniporter distinguish small calcium levels from a signal.","description":"Calcium-responsive EF hands in MICU1 and MICU2 allow the uniporter to pass from restrained low-calcium uptake to uptake above a threshold.","status":"provisional","compartment":{"slug":"mitochondrial-intermembrane-space","display_name":"Mitochondrial intermembrane space"},"participants":[{"entity":{"id":"e359bc15-e675-5d83-b0fe-1d70814e130b","slug":"calcium-ion","display_name":"Calcium ion","entity_type_key":"ion"},"role":"sensed_ligand","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"c2396324-d42c-57ce-94be-43ac8930329e","slug":"micu1","display_name":"Mitochondrial calcium uptake protein 1 / MICU1","entity_type_key":"protein"},"role":"calcium_sensor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"06ed2793-83d0-5ede-be7e-b6b3943a6157","slug":"micu2","display_name":"Mitochondrial calcium uptake protein 2 / MICU2","entity_type_key":"protein"},"role":"calcium_sensor","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"200eff80-420c-52f8-a4c5-4f5188b7b78b","slug":"mitochondrial-calcium-uniporter-complex","display_name":"Mitochondrial calcium uniporter complex","entity_type_key":"protein_complex"},"role":"regulated_channel_complex","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"05f933b8-964c-5007-9422-579ac96ba1d1","slug":"mitochondrial-intermembrane-space","display_name":"Mitochondrial intermembrane space","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":"Mitochondrial intermembrane-space regulatory subunits","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human HEK293T MICU1/MICU2 knockout and EF-hand mutant rescue; permeabilized-cell calcium clearance","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Knockout/rescue and permeabilized-cell evidence; numeric thresholds are not universal.","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":"MICU1 and MICU2 help the uniporter distinguish small calcium levels from a signal.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[ca-kamer2014] MICU1 and MICU2 play nonredundant roles in the regulation of the mitochondrial calcium uniporter (2014). https://pubmed.ncbi.nlm.nih.gov/24503055/ DOI: 10.1002/embr.201337946","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"research_relationship_category","value_text":"regulation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"HEK293T cells","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"57afd3cb-5d40-5ab1-ae91-6408df5f9204","evidence_kind":"source_excerpt","locator":"Lines 732-743","start_line":732,"end_line":743,"excerpt":"### ca-micu12-calcium-sensing\nCalcium-responsive EF hands in MICU1 and MICU2 allow the uniporter to pass from restrained low-calcium uptake to uptake above a threshold.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: MICU1 and MICU2 help the uniporter distinguish small calcium levels from a signal.\norganism: Homo sapiens\ntissue_or_cell_type: HEK293T cells\nexperimental_model: Human HEK293T MICU1/MICU2 knockout and EF-hand mutant rescue; permeabilized-cell calcium clearance\nlimitations: Knockout/rescue and permeabilized-cell evidence; numeric thresholds are not universal.\nresearch_relationship_category: regulation\ncompartment_description: Mitochondrial intermembrane-space regulatory subunits\n[ca-kamer2014] MICU1 and MICU2 play nonredundant roles in the regulation of the mitochondrial calcium uniporter (2014). https://pubmed.ncbi.nlm.nih.gov/24503055/ DOI: 10.1002/embr.201337946","model_system":"Human HEK293T MICU1/MICU2 knockout and EF-hand mutant rescue; permeabilized-cell calcium clearance","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [ca-kamer2014] MICU1 and MICU2 play nonredundant roles in the regulation of the mitochondrial calcium uniporter (2014). https://pubmed.ncbi.nlm.nih.gov/24503055/ DOI: 10.1002/embr.201337946","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}