{"doi":"10.1101/2023.01.31.526475","title":"FHF2 phosphorylation and regulation of native myocardial Na <sub>V</sub> 1.5 channels","abstract":"Abstract Phosphorylation of the cardiac Na V 1.5 channel pore-forming subunit is extensive and critical in modulating channel expression and function, yet the regulation of Na V 1.5 by phosphorylation of its accessory proteins remains elusive. Using a phosphoproteomic analysis of Na V channel complexes purified from mouse left ventricles, we identified nine phosphorylation sites on Fibroblast growth factor Homologous Factor 2 (FHF2). To determine the roles of phosphosites in regulating Na V 1.5, we developed two models from neonatal and adult mouse ventricular cardiomyocytes in which FHF2 expression is knockdown and rescued by WT, phosphosilent or phosphomimetic FHF2-VY. While the increased rates of closed-state and open-state inactivation of Na V channels induced by the FHF2 knockdown are completely restored by the FHF2-VY isoform in adult cardiomyocytes, sole a partial rescue is obtained in neonatal cardiomyocytes. The FHF2 knockdown also shifts the voltage-dependence of activation towards hyperpolarized potentials in neonatal cardiomyocytes, which is not rescued by FHF2-VY. Parallel investigations showed that the FHF2-VY isoform is predominant in adult cardiomyocytes, while expression of FHF2-VY and FHF2-A is comparable in neonatal cardiomyocytes. Similar to WT FHF2-VY, however, each FHF2-VY phosphomutant restores the Na V channel inactivation properties in both models, preventing identification of FHF2 phosphosite roles. FHF2 knockdown also increases the late Na + current in adult cardiomyocytes, which is restored similarly by WT and phosphosilent FHF2-VY. Together, our results demonstrate that ventricular FHF2 is highly phosphorylated, implicate differential roles for FHF2 in regulating neonatal and adult mouse ventricular Na V 1.5, and suggest that the regulation of Na V 1.5 by FHF2 phosphorylation is highly complex. eTOC Summary Lesage et al . identify the phosphorylation sites of FHF2 from mouse left ventricular Na V 1.5 channel complexes. While no roles for FHF2 phosphosites could be recognized yet, the findings demonstrate differential FHF2-dependent regulation of neonatal and adult mouse ventricular Na V 1.5 channels.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2023,"id":402851,"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":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9583,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":407658,"name":"Maxime Lorenzini","orcid":"0000-0001-5431-8274","position":1,"is_corresponding":false},{"id":407659,"name":"Sophie Burel","orcid":"0000-0003-0557-3396","position":2,"is_corresponding":false},{"id":1090433,"name":"Marine Sarlandie","orcid":"0009-0002-9887-0014","position":3,"is_corresponding":false},{"id":1090434,"name":"Floriane Bibault","orcid":"0009-0001-8212-0908","position":4,"is_corresponding":false},{"id":408364,"name":"Dan Maloney","orcid":null,"position":5,"is_corresponding":false},{"id":309267,"name":"Jonathan R. Silva","orcid":"0000-0002-3696-3955","position":6,"is_corresponding":false},{"id":2224,"name":"R. Reid Townsend","orcid":"0000-0002-0753-7594","position":7,"is_corresponding":false},{"id":395009,"name":"Jeanne M. Nerbonne","orcid":"0000-0001-8334-8499","position":8,"is_corresponding":false},{"id":407664,"name":"Céline Marionneau","orcid":"0000-0003-0962-9756","position":9,"is_corresponding":false},{"id":407660,"name":"Adrien Lesage","orcid":"0000-0002-8188-9168","position":0,"is_corresponding":true}],"reference_count":37,"raw_metadata":null,"created_at":"2026-07-19T01:20:32.588152Z","pmid":"36778222","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":[]}