{"doi":"10.17615/7eaq-3682","title":"Mechanism of Calmodulin Inhibition of Cardiac Sarcoplasmic Reticulum Ca2+ Release Channel (Ryanodine Receptor)","abstract":"The functional effects of calmodulin (CaM) on single cardiac sarcoplasmic reticulum Ca2+ release channels (ryanodine receptors) (RyR2s) were determined in the presence of two endogenous channel effectors, MgATP and reduced glutathione, using the planar lipid bilayer method. Single-channel activities, number of events, and open and close times were determined at varying cytosolic Ca2+ concentrations. CaM reduced channel open probability at μM Ca2+ by decreasing channel events and mean open times and increasing mean close times. At >10 μM Ca2+, CaM was less effective in inhibiting RyR2. CaM decreased mean open times but increased channel events, without significantly affecting mean close times. A series of voltage pulses was applied to the bilayer from +50 to −50 mV and from −50 mV to +50 mV to rapidly increase and decrease open channel-mediated sarcoplasmic reticulum lumenal to cytosolic Ca2+ fluxes. CaM decreased the duration of the open events after the voltage switch from −50 mV to +50 mV. In parallel experiments, a Ca2+-insensitive calmodulin mutant was without effect on RyR2 activity. The results are discussed in terms of a possible role of CaM in the termination of cardiac sarcoplasmic reticulum Ca2+ release.","journal":"UNC Libraries","year":2020,"id":115350,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9579,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":512917,"name":"Gerhard Meissner","orcid":"0000-0001-5185-4389","position":1,"is_corresponding":false},{"id":51645,"name":"Le Xu","orcid":"0000-0002-7910-3357","position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-18T23:13:36.820928Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}