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The fodrin breakdown was selective in that calpain I did not affect at least 15 other membrane-associated polypeptides. Fodrin degradation by the protease was rapid and was accompanied by the appearance of a lower molecular weight breakdown product. Calpain I had a high affinity for fodrin, with a Km for degradation of about 50 nM. Purified calpain I also degraded purified spectrin and the spectrin present in erythrocyte membranes. Calpain I-mediated degradation of spectrin-like proteins could provide a mechanism by which brief increases in intracellular free calcium levels modify the structure of the submembraneous cytoskeleton and the distribution of cell surface receptors and alter cell shape.</jats:p>","journal":"Proceedings of the National Academy of Sciences","year":1984,"id":679530,"datarank":0.855066536008603,"base_score":5.700443573390686,"endowment":5.700443573390686,"self_citation_contribution":0.855066536008603,"citation_network_contribution":0.0,"self_endowment_contribution":0.855066536008603,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":298,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1775463,"name":"M Baudry","orcid":null,"position":1,"is_corresponding":false},{"id":524539,"name":"G Lynch","orcid":null,"position":2,"is_corresponding":false},{"id":1775462,"name":"R Siman","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Brain fodrin: substrate for calpain I, an endogenous calcium-activated protease.","abstract":"<jats:p>The calcium-activated thiol-protease calpain I, which is present in cytosolic and membrane preparations from rat brain, was tested for its capacity to degrade the neuronal spectrin-like protein fodrin. 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