Cardiac ryanodine receptor distribution is dynamic and changed by auxiliary proteins and post-translational modification
Abstract
The effects of the immunophilins, FKBP12 and FKBP12.6, and phosphorylation on type II ryanodine receptor (RyR2) arrangement and function were examined using correlation microscopy (line scan confocal imaging of Ca2+ sparks and dual-tilt electron tomography) and dSTORM imaging of permeabilized Wistar rat ventricular myocytes. Saturating concentrations (10 µmol/L) of either FKBP12 or 12.6 significantly reduced the frequency, spread, amplitude and Ca2+ spark mass relative to control, while the tomograms revealed both proteins shifted the tetramers into a largely side-by-side configuration. Phosphorylation of immunophilin-saturated RyR2 resulted in structural and functional changes largely comparable to phosphorylation alone. dSTORM images of myocyte surfaces demonstrated that both FKBP12 and 12.6 significantly reduced RyR2 cluster sizes, while phosphorylation, even of immunophilin-saturated RyR2, increased them. We conclude that both RyR2 cluster size and the arrangement of tetramers within clusters is dynamic and respond to changes in the cellular environment. Further, these changes affect Ca2+ spark formation.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided where required.
Article and author information
Author details
Funding
Canadian Institutes of Health Research (148527)
- Edwin DW Moore
Canadian Institutes of Health Research (PJT-153305)
- Filip van Petegem
Natural Sciences and Engineering Research Council of Canada
- Keng C Chou
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations provided by the Canadian Council on Animal Care. All of the animals were handled according to a protocol (A17-0040) approved by the Animal Care Committee of the University of British Columbia.
Copyright
© 2020, Asghari et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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