{"id":"2de86c9e-6ef1-504e-a917-d28b314b11ba","stable_key":"2921131d-0ba0-51d3-8f59-8c4be3b9ac08:cucurbitacin-e-f-actin","predicate":"covalently_modifies_tested","statement":"Cucurbitacin E covalently modified actin at Cys257 in F-actin and inhibited depolymerization, with effects at substoichiometric compound:actin ratios down to 1:6.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"6ffeab1d-d2ea-560c-b99e-084c2f1c744d","mechanism_event_label":"The filament itself can be stabilized.","subject":{"id":"d5631638-0ee3-537f-b7cc-cbd4958395d3","slug":"cucurbitacin-e","display_name":"Cucurbitacin E","entity_type_key":"small_molecule"},"object":{"id":"24579623-993e-5330-801b-b438cf595a0b","slug":"purified-cucurbitacin-f-actin","display_name":"Purified F-actin in cucurbitacin assays, species as reported","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"6ffeab1d-d2ea-560c-b99e-084c2f1c744d","stable_key":"2921131d-0ba0-51d3-8f59-8c4be3b9ac08:cucurbitacin-e-f-actin-event","event_type":"observed_relationship","label":"The filament itself can be stabilized.","description":"Cucurbitacin E covalently modified actin at Cys257 in F-actin and inhibited depolymerization, with effects at substoichiometric compound:actin ratios down to 1:6.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"d5631638-0ee3-537f-b7cc-cbd4958395d3","slug":"cucurbitacin-e","display_name":"Cucurbitacin E","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"24579623-993e-5330-801b-b438cf595a0b","slug":"purified-cucurbitacin-f-actin","display_name":"Purified F-actin in cucurbitacin assays, species as reported","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"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":2,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified actin and cellular photoactivation experiments.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Purified actin species/isoform not established from the accessed abstract; not automatically human ACTB. This study did not find an effect on polymerization.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Cucurbitacins collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"cucurbitacin","display_name":"Cucurbitacins","entity_type_key":"chemical_species"}},{"dimension":"plain_language","value_text":"The filament itself can be stabilized.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"The natural product cucurbitacin E inhibits depolymerization of actin filaments. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22724897/ · DOI 10.1021/cb300254s","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"c6e8aaaa-942b-5821-a4f9-2a3c7f9436eb","evidence_kind":"source_excerpt","locator":"Lines 52-58","start_line":52,"end_line":58,"excerpt":"## cucurbitacin-e-f-actin\nThe filament itself can be stabilized.\nCucurbitacin E covalently modified actin at Cys257 in F-actin and inhibited depolymerization, with effects at substoichiometric compound:actin ratios down to 1:6.\nModel: Purified actin and cellular photoactivation experiments.\nLimitations: Purified actin species/isoform not established from the accessed abstract; not automatically human ACTB. This study did not find an effect on polymerization.\nEvidence access: Primary abstract\nThe natural product cucurbitacin E inhibits depolymerization of actin filaments. · 2012 · https://pubmed.ncbi.nlm.nih.gov/22724897/ · DOI 10.1021/cb300254s","model_system":"Purified actin and cellular photoactivation experiments.","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":"77324310-00ce-5d28-9fc7-595fddae86b9","stable_key":"import-2921131d-0ba0-51d3-8f59-8c4be3b9ac08","title":"Cucurbitacins: thiol chemistry, cytoskeleton, metabolic dependencies and signaling (2026-09-20)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text.","file_path":"","sha256":"5c23ec61b9cf3d2966fb081d8617e1e1f7c522e86419b8ba2dcae09590121123","revision_id":"74251a06-3ba5-506c-b428-700eca0fb432","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}