Ryanodine receptor Ca2+ release channels: does diversity in form equal diversity in function?

1996 ◽  
Vol 76 (4) ◽  
pp. 1027-1071 ◽  
Author(s):  
J. L. Sutko ◽  
J. A. Airey

Complexities in calcium signaling in eukaryotic cells require diversity in the proteins involved in generating these signals. In this review, we consider the ryanodine receptor (RyR) family of intracellular calcium release channels. This includes species, tissue, and cellular distributions of the RyRs and mechanisms of activation, deactivation, and inactivation of RyR calcium release events. In addition, as first observed in nonmammalian vertebrate skeletal muscles, it is now clear that more than one RyR isoform is frequently coexpressed within many cell types. How multiple ryanodine receptor release channels are used to generate intracellular calcium transients is unknown. Therefore, a primary focus of this review is why more than one RyR is required for this purpose, particularly in a tissue, such as vertebrate fast-twitch skeletal muscles, where a relatively simple and straightforward change in calcium would appear to be required to elicit contraction. Finally, the roles of the RyR isoforms and the calcium release events they mediate in the development of embryonic skeletal muscle are considered.

1995 ◽  
Vol 128 (5) ◽  
pp. 893-904 ◽  
Author(s):  
G Giannini ◽  
A Conti ◽  
S Mammarella ◽  
M Scrobogna ◽  
V Sorrentino

Ryanodine receptors (RyRs) are intracellular calcium release channels that participate in controlling cytosolic calcium levels. At variance with the probably ubiquitous inositol 1,4,5-trisphosphate-operated calcium channels (1,4,5-trisphosphate receptors), RyRs have been mainly regarded as the calcium release channels controlling skeletal and cardiac muscle contraction. Increasing evidence has recently suggested that RyRs may be more widely expressed, but this has never been extensively examined. Therefore, we cloned three cDNAs corresponding to murine RyR homologues to carry a comprehensive analysis of their expression in murine tissues. Here, we report that the three genes are expressed in almost all tissues analyzed, where tissue-specific patterns of expression were observed. In the uterus and vas deferens, expression of RyR3 was localized to the smooth muscle component of these organs. In the testis, expression of RyR1 and RyR3 was detected in germ cells. RyR mRNAs were also detected in in vitro-cultured cell lines. RyR1, RyR2, and RyR3 mRNA were detected in the cerebrum and in the cerebellum. In situ analysis revealed a cell type-specific pattern of expression in the different regions of the central nervous system. The differential expression of the three ryanodine receptor genes in the central nervous system was also confirmed using specific antibodies against the respective proteins. This widespread pattern of expression suggests that RyRs may participate in the regulation of intracellular calcium homeostasis in a range of cells wider than previously recognized.


2021 ◽  
Vol 12 (11) ◽  
Author(s):  
Yvonne Sleiman ◽  
Alain Lacampagne ◽  
Albano C. Meli

AbstractThe regulation of intracellular calcium (Ca2+) homeostasis is fundamental to maintain normal functions in many cell types. The ryanodine receptor (RyR), the largest intracellular calcium release channel located on the sarco/endoplasmic reticulum (SR/ER), plays a key role in the intracellular Ca2+ handling. Abnormal type 2 ryanodine receptor (RyR2) function, associated to mutations (ryanopathies) or pathological remodeling, has been reported, not only in cardiac diseases, but also in neuronal and pancreatic disorders. While animal models and in vitro studies provided valuable contributions to our knowledge on RyR2 dysfunctions, the human cell models derived from patients’ cells offer new hope for improving our understanding of human clinical diseases and enrich the development of great medical advances. We here discuss the current knowledge on RyR2 dysfunctions associated with mutations and post-translational remodeling. We then reviewed the novel human cellular technologies allowing the correlation of patient’s genome with their cellular environment and providing approaches for personalized RyR-targeted therapeutics.


2014 ◽  
Vol 459 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Spyros Zissimopoulos ◽  
Jason Marsh ◽  
Laurence Stannard ◽  
Monika Seidel ◽  
F. Anthony Lai

Intracellular Ca2+ channels are of paramount importance for numerous cellular processes. In the present paper we report on a novel N-terminus intersubunit interaction, an essential structure–function parameter, which is conserved in both families of intracellular Ca2+ channels.


2000 ◽  
Vol 28 (1) ◽  
pp. A18-A18
Author(s):  
C. O'Neill ◽  
J. Fastbom ◽  
R. Cowburn ◽  
M. Carmody ◽  
T.G. Ohm ◽  
...  

2019 ◽  
Vol 97 (5) ◽  
pp. 429-435 ◽  
Author(s):  
Ian C. Smith ◽  
Rene Vandenboom ◽  
A. Russell Tupling

The amount of calcium released from the sarcoplasmic reticulum in skeletal muscle rapidly declines during repeated twitch contractions. In this study, we test the hypothesis that caffeine can mitigate these contraction-induced declines in calcium release. Lumbrical muscles were isolated from male C57BL/6 mice and loaded with the calcium-sensitive indicator, AM-furaptra. Muscles were then stimulated at 8 Hz for 2.0 s in the presence or absence of 0.5 mM caffeine, at either 30 °C or 37 °C. The amplitude and area of the furaptra-based intracellular calcium transients and force produced during twitch contractions were calculated. For each of these measures, the values for twitch 16 relative to twitch 1 were higher in the presence of caffeine than in the absence of caffeine at both temperatures. We conclude that caffeine can attenuate contraction-induced diminutions of calcium release during repeated twitch contractions, thereby contributing to the inotropic effects of caffeine.


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