{"id":"8dc32133-f39d-5367-8856-276f33cd4986","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-serine-starvation-methylation","predicate":"when_withdrawn_reduces","statement":"Serine starvation increased the methionine/SAM ratio and reduced methyl-group transfer to DNA and RNA; ATP and AMP fell without AMPK activation.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"c18969c8-f540-55d5-880d-7b3132a07569","mechanism_event_label":"A shortage can alter methylation without a simple energy-sensor response.","subject":{"id":"c882cd0b-9d83-5b07-bd1c-fe4d45657dcb","slug":"l-serine","display_name":"L-Serine","entity_type_key":"small_molecule"},"object":{"id":"9e91b6e3-fb2b-5b0b-8b3d-d365e6fde973","slug":"human-serine-starvation-methyl-transfer","display_name":"DNA/RNA methyl transfer during serine starvation","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"c18969c8-f540-55d5-880d-7b3132a07569","stable_key":"649e861b-265a-5912-bc36-3a73e53ef892:l-serine-serine-starvation-methylation-event","event_type":"observed_relationship","label":"A shortage can alter methylation without a simple energy-sensor response.","description":"Serine starvation increased the methionine/SAM ratio and reduced methyl-group transfer to DNA and RNA; ATP and AMP fell without AMPK activation.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"c882cd0b-9d83-5b07-bd1c-fe4d45657dcb","slug":"l-serine","display_name":"L-Serine","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"9e91b6e3-fb2b-5b0b-8b3d-d365e6fde973","slug":"human-serine-starvation-methyl-transfer","display_name":"DNA/RNA methyl transfer during serine starvation","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"825f2da2-01bc-5874-a3c6-64f5ac867db5","slug":"s-adenosylmethionine","display_name":"S-Adenosyl-L-methionine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human cancer-cell starvation experiments.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"No universal oncogene activation, whole-body methylation collapse or dietary threshold is established.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-serine","display_name":"L-Serine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"A shortage can alter methylation without a simple energy-sensor response.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Serine Metabolism Supports the Methionine Cycle and DNA/RNA Methylation through De Novo ATP Synthesis in Cancer Cells. · 2016 · https://pubmed.ncbi.nlm.nih.gov/26774282/ · DOI 10.1016/j.molcel.2015.12.014","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"ea916223-a0b4-523d-839b-63b02357eee1","evidence_kind":"source_excerpt","locator":"Lines 190-196","start_line":190,"end_line":196,"excerpt":"## l-serine-serine-starvation-methylation\nA shortage can alter methylation without a simple energy-sensor response.\nSerine starvation increased the methionine/SAM ratio and reduced methyl-group transfer to DNA and RNA; ATP and AMP fell without AMPK activation.\nModel: Human cancer-cell starvation experiments.\nLimitations: No universal oncogene activation, whole-body methylation collapse or dietary threshold is established.\nEvidence access: Primary abstract\nSerine Metabolism Supports the Methionine Cycle and DNA/RNA Methylation through De Novo ATP Synthesis in Cancer Cells. · 2016 · https://pubmed.ncbi.nlm.nih.gov/26774282/ · DOI 10.1016/j.molcel.2015.12.014","model_system":"Human cancer-cell starvation 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":"70bcf57a-36bb-563f-9073-2d616e5f155a","stable_key":"import-649e861b-265a-5912-bc36-3a73e53ef892","title":"L-Serine: synthesis, one-carbon metabolism, lipids and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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