Enhancement of Calmodulin Binding to Cardiac Ryanodine Receptor Corrects the Defective Channel Gating in Failing Hearts

2011 ◽  
Vol 17 (9) ◽  
pp. S170
Author(s):  
Akihiro Hino ◽  
Masafumi Yano ◽  
Takayoshi Katoh ◽  
Masakazu Fukuda ◽  
Takeshi Suetomi ◽  
...  
Keyword(s):  
Ryanodine Receptor ◽  
Channel Gating ◽  
Calmodulin Binding ◽  
Cardiac Ryanodine Receptor

scholarly journals The arrhythmogenic N53I variant subtly changes the structure and dynamics in the calmodulin N-terminal domain, altering its interaction with the cardiac ryanodine receptor

2020 ◽  
Vol 295 (22) ◽  
pp. 7620-7634
Author(s):  
Christian Holt ◽  
Louise Hamborg ◽  
Kelvin Lau ◽  
Malene Brohus ◽  
Anders Bundgaard Sørensen ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Ryanodine Receptor ◽  
Hydrophobic Surface ◽  
Catecholaminergic Polymorphic Ventricular Tachycardia ◽  
Polymorphic Ventricular Tachycardia ◽  
Open Probability ◽  
Calmodulin Binding ◽  
Terminal Domain ◽  
Genes Encoding ◽  
Cardiac Ryanodine Receptor

Mutations in the genes encoding the highly conserved Ca2+-sensing protein calmodulin (CaM) cause severe cardiac arrhythmias, including catecholaminergic polymorphic ventricular tachycardia or long QT syndrome and sudden cardiac death. Most of the identified arrhythmogenic mutations reside in the C-terminal domain of CaM and mostly affect Ca2+-coordinating residues. One exception is the catecholaminergic polymorphic ventricular tachycardia–causing N53I substitution, which resides in the N-terminal domain (N-domain). It does not affect Ca2+ coordination and has only a minor impact on binding affinity toward Ca2+ and on other biophysical properties. Nevertheless, the N53I substitution dramatically affects CaM's ability to reduce the open probability of the cardiac ryanodine receptor (RyR2) while having no effect on the regulation of the plasmalemmal voltage-gated Ca2+ channel, Cav1.2. To gain more insight into the molecular disease mechanism of this mutant, we used NMR to investigate the structures and dynamics of both apo- and Ca2+-bound CaM-N53I in solution. We also solved the crystal structures of WT and N53I CaM in complex with the primary calmodulin-binding domain (CaMBD2) from RyR2 at 1.84–2.13 Å resolutions. We found that all structures of the arrhythmogenic CaM-N53I variant are highly similar to those of WT CaM. However, we noted that the N53I substitution exposes an additional hydrophobic surface and that the intramolecular dynamics of the protein are significantly altered such that they destabilize the CaM N-domain. We conclude that the N53I-induced changes alter the interaction of the CaM N-domain with RyR2 and thereby likely cause the arrhythmogenic phenotype of this mutation.

scholarly journals The Cytoplasmic Region of Inner Helix S6 Is an Important Determinant of Cardiac Ryanodine Receptor Channel Gating

2016 ◽  
Vol 291 (50) ◽  
pp. 26024-26034 ◽  
Author(s):  
Bo Sun ◽  
Wenting Guo ◽  
Xixi Tian ◽  
Jinjing Yao ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Ryanodine Receptor ◽  
Important Determinant ◽  
Channel Gating ◽  
Cytoplasmic Region ◽  
Receptor Channel ◽  
Cardiac Ryanodine Receptor

scholarly journals Effect of sphingosylphosphorylcholine on the single channel gating properties of the cardiac ryanodine receptor

FEBS Letters ◽  
1999 ◽  
Vol 460 (3) ◽  
pp. 467-471 ◽  
Author(s):  
Akira Uehara ◽  
Midori Yasukochi ◽  
Issei Imanaga ◽  
Joshua R. Berlin
Keyword(s):  
Ryanodine Receptor ◽  
Single Channel ◽  
Channel Gating ◽  
Cardiac Ryanodine Receptor

Correction of Defective Calmodulin Binding to the Cardiac Ryanodine Receptor Inhibits Aberrant Ca2+ Release in CPVT-associated Channel Dysfunction

2012 ◽  
Vol 18 (10) ◽  
pp. S188
Author(s):  
Masakazu Fukuda ◽  
Masafumi Yano ◽  
Takayoshi Kato ◽  
Hiroki Tateishi ◽  
Masahiro Doi ◽  
...  
Keyword(s):  
Ryanodine Receptor ◽  
Calmodulin Binding ◽  
Cardiac Ryanodine Receptor

scholarly journals Ca2+-dependent calmodulin binding to cardiac ryanodine receptor (RyR2) calmodulin-binding domains

2019 ◽  
Vol 476 (2) ◽  
pp. 193-209 ◽  
Author(s):  
Malene Brohus ◽  
Mads T. Søndergaard ◽  
Sui Rong Wayne Chen ◽  
Filip van Petegem ◽  
Michael T. Overgaard
Keyword(s):  
Ryanodine Receptor ◽  
Fluorescence Anisotropy ◽  
Dependent Manner ◽  
Binding Model ◽  
Calmodulin Binding ◽  
Binding Domains ◽  
Wide Range ◽  
Dependent Inhibition ◽  
Life Threatening ◽  
Cardiac Ryanodine Receptor

Abstract The Ca2+ sensor calmodulin (CaM) regulates cardiac ryanodine receptor (RyR2)-mediated Ca2+ release from the sarcoplasmic reticulum. CaM inhibits RyR2 in a Ca2+-dependent manner and aberrant CaM-dependent inhibition results in life-threatening cardiac arrhythmias. However, the molecular details of the CaM–RyR2 interaction remain unclear. Four CaM-binding domains (CaMBD1a, -1b, -2, and -3) in RyR2 have been proposed. Here, we investigated the Ca2+-dependent interactions between CaM and these CaMBDs by monitoring changes in the fluorescence anisotropy of carboxytetramethylrhodamine (TAMRA)-labeled CaMBD peptides during titration with CaM at a wide range of Ca2+ concentrations. We showed that CaM bound to all four CaMBDs with affinities that increased with Ca2+ concentration. CaM bound to CaMBD2 and -3 with high affinities across all Ca2+ concentrations tested, but bound to CaMBD1a and -1b only at Ca2+ concentrations above 0.2 µM. Binding experiments using individual CaM domains revealed that the CaM C-domain preferentially bound to CaMBD2, and the N-domain to CaMBD3. Moreover, the Ca2+ affinity of the CaM C-domain in complex with CaMBD2 or -3 was so high that these complexes are essentially Ca2+ saturated under resting Ca2+ conditions. Conversely, the N-domain senses Ca2+ exactly in the transition from resting to activating Ca2+ when complexed to either CaMBD2 or -3. Altogether, our results support a binding model where the CaM C-domain is anchored to RyR2 CaMBD2 and saturated with Ca2+ during Ca2+ oscillations, while the CaM N-domain functions as a dynamic Ca2+ sensor that can bridge noncontiguous regions of RyR2 or clamp down onto CaMBD2.

scholarly journals Defective calmodulin binding to the cardiac ryanodine receptor plays a key role in CPVT-associated channel dysfunction

2010 ◽  
Vol 394 (3) ◽  
pp. 660-666 ◽  
Author(s):  
Xiaojuan Xu ◽  
Masafumi Yano ◽  
Hitoshi Uchinoumi ◽  
Akihiro Hino ◽  
Takeshi Suetomi ◽  
...  
Keyword(s):  
Ryanodine Receptor ◽  
Calmodulin Binding ◽  
Cardiac Ryanodine Receptor

scholarly journals Enhancing calmodulin binding to cardiac ryanodine receptor completely inhibits pressure-overload induced hypertrophic signaling

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Michiaki Kohno ◽  
Shigeki Kobayashi ◽  
Takeshi Yamamoto ◽  
Ryosuke Yoshitomi ◽  
Toshiro Kajii ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Binding Affinity ◽  
Ryanodine Receptor ◽  
Contractile Function ◽  
Pressure Overload ◽  
Cardiac Contractile Function ◽  
Calmodulin Binding ◽  
Intracellular Ca ◽  
Hypertrophic Signaling ◽  
Cardiac Ryanodine Receptor

AbstractCardiac hypertrophy is a well-known major risk factor for poor prognosis in patients with cardiovascular diseases. Dysregulation of intracellular Ca2+ is involved in the pathogenesis of cardiac hypertrophy. However, the precise mechanism underlying cardiac hypertrophy remains elusive. Here, we investigate whether pressure-overload induced hypertrophy can be induced by destabilization of cardiac ryanodine receptor (RyR2) through calmodulin (CaM) dissociation and subsequent Ca2+ leakage, and whether it can be genetically rescued by enhancing the binding affinity of CaM to RyR2. In the very initial phase of pressure-overload induced cardiac hypertrophy, when cardiac contractile function is preserved, reactive oxygen species (ROS)-mediated RyR2 destabilization already occurs in association with relaxation dysfunction. Further, stabilizing RyR2 by enhancing the binding affinity of CaM to RyR2 completely inhibits hypertrophic signaling and improves survival. Our study uncovers a critical missing link between RyR2 destabilization and cardiac hypertrophy.

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