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Updated: Jun 22, 2026
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Functional Characterization of Endogenously Expressed Human RYR1 Variants
Published on: June 9, 2021
Temperature acclimation has no effect on ryanodine receptor expression or subcellular localization in rainbow trout
Rikke Birkedal1, Jennifer Christopher, Angela Thistlethwaite
1Faculty of Life Sciences, The University of Manchester, Core Technology Facility 46 Grafton Street, Manchester, M13 9NT, UK. rikke@sysbio.ioc.ee
Summary
Temperature acclimation did not alter ryanodine receptor (RYR) expression or localization in rainbow trout cardiomyocytes. RYRs remained localized at the m-line, suggesting reliance on transsarcolemmal calcium influx for excitation-contraction coupling.
Area of Science:
- Cardiovascular Physiology
- Cellular Biology
- Aquatic Animal Physiology
Background:
- Ryanodine receptors (RYRs) are crucial for calcium-induced calcium-release (CICR) in cardiomyocytes during excitation-contraction (e-c) coupling.
- In rainbow trout, the reliance on CICR increases with cold acclimation, suggesting temperature-dependent adaptations in calcium handling.
Purpose of the Study:
- To investigate the impact of temperature acclimation on the intracellular localization and expression density of RYRs in rainbow trout.
- To determine if changes in RYR localization or expression correlate with altered reliance on CICR at different temperatures.
Main Methods:
- Immunocytochemistry was employed to visualize RYR intracellular localization in ventricular myocytes.
- Western blotting was used to quantify RYR expression levels in both atrial and ventricular tissues across different acclimation temperatures (4, 11, and 18°C).
Main Results:
- RYRs were consistently localized in peripheral transverse bands aligned with sarcomeric m-lines, as well as centrally around mitochondria and the nucleus in ventricular myocytes.
- Neither RYR intracellular localization nor expression density was significantly affected by temperature acclimation.
- The observed m-line localization is characteristic of mammalian neonatal cardiomyocytes, implying a different calcium handling mechanism.
Conclusions:
- Temperature acclimation does not alter RYR expression or localization in rainbow trout cardiomyocytes.
- The persistent peripheral m-line localization of RYRs suggests that rainbow trout ventricular myocytes may primarily utilize transsarcolemmal calcium influx for excitation-contraction coupling, rather than robust CICR, irrespective of acclimation temperature.
