{"id":"56951b66-55ca-5ea0-92b7-3b6fd4cf6edb","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:osteoclast-lacuna-acidification","predicate":"drives","statement":"Resorbing osteoclasts acidified the extracellular compartment beneath their ruffled border and reacidified it after ammonium chloride washout.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"88f856c4-e003-58eb-8cd1-ed49d846299d","mechanism_event_label":"Bone-resorbing cells create a locally acidic space against bone.","subject":{"id":"404fc748-a4da-5661-b3dd-690db50d5a09","slug":"osteoclast","display_name":"Osteoclast","entity_type_key":"cell_type"},"object":{"id":"c3612fd4-14ab-53be-8914-31bb06fb1ef9","slug":"resorption-lacuna-acidification","display_name":"Acidification of the osteoclast resorption lacuna","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"88f856c4-e003-58eb-8cd1-ed49d846299d","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:osteoclast-lacuna-acidification-event","event_type":"biochemical_relationship","label":"Bone-resorbing cells create a locally acidic space against bone.","description":"Resorbing osteoclasts acidified the extracellular compartment beneath their ruffled border and reacidified it after ammonium chloride washout.","status":"provisional","compartment":{"slug":"osteoclast-resorption-lacuna","display_name":"Osteoclast resorption lacuna"},"participants":[{"entity":{"id":"404fc748-a4da-5661-b3dd-690db50d5a09","slug":"osteoclast","display_name":"Osteoclast","entity_type_key":"cell_type"},"role":"acidifying_cell","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"1ed0233a-3d10-58b3-abda-8ad04545c495","slug":"proton","display_name":"Proton","entity_type_key":"ion"},"role":"acidifying_species","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"26cd494e-fbae-5a20-b7a6-30280e1913d6","slug":"osteoclast-resorption-lacuna","display_name":"Osteoclast resorption lacuna","entity_type_key":"organelle"},"role":"acidified_compartment","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"7dbb4c2f-3f94-5f0b-abfc-980d8a4105d5","slug":"bone-extracellular-matrix","display_name":"Bone extracellular matrix","entity_type_key":"tissue"},"role":"adjacent_resorbed_matrix","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"26cd494e-fbae-5a20-b7a6-30280e1913d6","slug":"osteoclast-resorption-lacuna","display_name":"Osteoclast resorption lacuna","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."},{"entity":{"id":"c3612fd4-14ab-53be-8914-31bb06fb1ef9","slug":"resorption-lacuna-acidification","display_name":"Acidification of the osteoclast resorption lacuna","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""}]},"contexts":[{"dimension":"compartment_description","value_text":"Sealed extracellular resorption lacuna","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Acridine-orange localization and reversible pH perturbation","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"This study localizes acidification; it does not identify a particular modern proton-pump subunit or measure whole-body calcium flux.","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":"Gallus gallus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Bone-resorbing cells create a locally acidic space against bone.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[baron1985] Cell-mediated extracellular acidification and bone resorption: evidence for a low pH in resorbing lacunae and localization of a 100-kD lysosomal membrane protein at the osteoclast ruffled border (1985). https://rupress.org/jcb/article/101/6/2210/21648/Cell-mediated-extracellular-acidification-and-bone DOI: 10.1083/jcb.101.6.2210","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Osteoclast-bone interface","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"9b91d27f-0a19-5e2d-af19-70d11da4c0ad","evidence_kind":"source_excerpt","locator":"Lines 1081-1091","start_line":1081,"end_line":1091,"excerpt":"### osteoclast-lacuna-acidification\nResorbing osteoclasts acidified the extracellular compartment beneath their ruffled border and reacidified it after ammonium chloride washout.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Bone-resorbing cells create a locally acidic space against bone.\norganism: Gallus gallus\ntissue_or_cell_type: Osteoclast-bone interface\nexperimental_model: Acridine-orange localization and reversible pH perturbation\nlimitations: This study localizes acidification; it does not identify a particular modern proton-pump subunit or measure whole-body calcium flux.\ncompartment_description: Sealed extracellular resorption lacuna\n[baron1985] Cell-mediated extracellular acidification and bone resorption: evidence for a low pH in resorbing lacunae and localization of a 100-kD lysosomal membrane protein at the osteoclast ruffled border (1985). https://rupress.org/jcb/article/101/6/2210/21648/Cell-mediated-extracellular-acidification-and-bone DOI: 10.1083/jcb.101.6.2210","model_system":"Acridine-orange localization and reversible pH perturbation","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [baron1985] Cell-mediated extracellular acidification and bone resorption: evidence for a low pH in resorbing lacunae and localization of a 100-kD lysosomal membrane protein at the osteoclast ruffled border (1985). https://rupress.org/jcb/article/101/6/2210/21648/Cell-mediated-extracellular-acidification-and-bone DOI: 10.1083/jcb.101.6.2210","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. 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