Calmodulin inhibition of human RyR2 channels requires phosphorylation of RyR2-S2808 or RyR2-S2814
| Autor: | Cris dos Remedios, Bjorn C. Knollmann, Nicole A. Beard, Ye Wint Oo, Nieves Gomez-Hurtado, Peter C. M. Molenaar, Robyn T. Rebbeck, Derek R. Laver, Razvan L. Cornea, Kafa Walweel, Dirk F. van Helden |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Calmodulin Hyperphosphorylation 030204 cardiovascular system & hematology Article Dephosphorylation 03 medical and health sciences 0302 clinical medicine Ca2+/calmodulin-dependent protein kinase Humans Myocytes Cardiac Phosphorylation Protein kinase A Molecular Biology Heart Failure biology Ryanodine receptor Chemistry Kinase Ryanodine Receptor Calcium Release Channel musculoskeletal system Cyclic AMP-Dependent Protein Kinases Cell biology 030104 developmental biology cardiovascular system biology.protein Calcium-Calmodulin-Dependent Protein Kinase Type 2 Cardiology and Cardiovascular Medicine tissues Protein Binding |
| Zdroj: | Journal of Molecular and Cellular Cardiology. 130:96-106 |
| ISSN: | 0022-2828 |
| Popis: | Calmodulin (CaM) is a Ca-binding protein that binds to, and can directly inhibit cardiac ryanodine receptor calcium release channels (RyR2). Animal studies have shown that RyR2 hyperphosphorylation reduces CaM binding to RyR2 in failing hearts, but data are lacking on how CaM regulates human RyR2 and how this regulation is affected by RyR2 phosphorylation. Physiological concentrations of CaM (100 nM) inhibited the diastolic activity of RyR2 isolated from failing human hearts by ~50% but had no effect on RyR2 from healthy human hearts. Using FRET between donor-FKBP12.6 and acceptor-CaM bound to RyR2, we determined that CaM binds to RyR2 from healthy human heart with a K(d) = 121 ± 14 nM. Ex-vivo phosphorylation/dephosphorylation experiments suggested that the divergent CaM regulation of healthy and failing human RyR2 was caused by differences in RyR2 phosphorylation by protein kinase A and Ca-CaM-dependent kinase II. Ca(2+)-spark measurements in murine cardiomyocytes harbouring RyR2 phosphomimetic or phosphoablated mutants at S2814 and S2808 suggest that phosphorylation of residues corresponding to either human RyR2-S2808 or S2814 is both necessary and sufficient for RyR2 regulation by CaM. Our results challenge the current concept that CaM universally functions as a canonical inhibitor of RyR2 across species. Rather, CaM’s biological action on human RyR2 appears to be more nuanced, with inhibitory activity only on phosphorylated RyR2 channels, which occurs during exercise or in patients with heart failure. |
| Databáze: | OpenAIRE |
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