Role of cardiac ryanodine receptor calmodulin‐binding domains in mediating the action of arrhythmogenic calmodulin N‐domain mutation N54I

FEBS Journal ◽  
2019 ◽  
Vol 287 (11) ◽  
pp. 2256-2280 ◽  
Author(s):  
Mads T. Søndergaard ◽  
Yingjie Liu ◽  
Wenting Guo ◽  
Jinhong Wei ◽  
Ruiwu Wang ◽  
...  
2019 ◽  
Vol 476 (2) ◽  
pp. 193-209 ◽  
Author(s):  
Malene Brohus ◽  
Mads T. Søndergaard ◽  
Sui Rong Wayne Chen ◽  
Filip van Petegem ◽  
Michael T. Overgaard

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.


2020 ◽  
Vol 295 (22) ◽  
pp. 7620-7634
Author(s):  
Christian Holt ◽  
Louise Hamborg ◽  
Kelvin Lau ◽  
Malene Brohus ◽  
Anders Bundgaard Sørensen ◽  
...  

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.


2012 ◽  
Vol 18 (10) ◽  
pp. S188
Author(s):  
Masakazu Fukuda ◽  
Masafumi Yano ◽  
Takayoshi Kato ◽  
Hiroki Tateishi ◽  
Masahiro Doi ◽  
...  

2004 ◽  
Vol 86 (4) ◽  
pp. 2121-2128 ◽  
Author(s):  
Inna Györke ◽  
Nichole Hester ◽  
Larry R. Jones ◽  
Sandor Györke

2011 ◽  
Vol 17 (9) ◽  
pp. S170
Author(s):  
Akihiro Hino ◽  
Masafumi Yano ◽  
Takayoshi Katoh ◽  
Masakazu Fukuda ◽  
Takeshi Suetomi ◽  
...  

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

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Michiaki Kohno ◽  
Shigeki Kobayashi ◽  
Takeshi Yamamoto ◽  
Ryosuke Yoshitomi ◽  
Toshiro Kajii ◽  
...  

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.


Biochemistry ◽  
2006 ◽  
Vol 45 (41) ◽  
pp. 12519-12529 ◽  
Author(s):  
Gianni Colotti ◽  
Carlotta Zamparelli ◽  
Daniela Verzili ◽  
Manuela Mella ◽  
Christopher M. Loughrey ◽  
...  

2006 ◽  
Vol 290 (2) ◽  
pp. H794-H799 ◽  
Author(s):  
Edward M. Balog ◽  
Laura E. Norton ◽  
David D. Thomas ◽  
Bradley R. Fruen

Calmodulin (CaM) binds to the cardiac ryanodine receptor Ca2+ release channel (RyR2) with high affinity and may act as a regulatory channel subunit. Here we determine the role of CaM Met residues in the productive association of CaM with RyR2, as assessed via determinations of [3H]ryanodine and [35S]CaM binding to cardiac muscle sarcoplasmic reticulum (SR) vesicles. Oxidation of all nine CaM Met residues abolished the productive association of CaM with RyR2. Substitution of the COOH-terminal Mets of CaM with Leu decreased the extent of CaM inhibition of cardiac SR (CSR) vesicle [3H]ryanodine binding. In contrast, replacing the NH2-terminal Met of CaM with Leu increased the concentration of CaM required to inhibit CSR [3H]ryanodine binding but did not alter the extent of inhibition. Site-specific substitution of individual CaM Met residues with Gln demonstrated that Met124 was required for both high-affinity CaM binding to RyR2 and for maximal CaM inhibition. These results thus identify a Met residue critical for the productive association of CaM with RyR2 channels.


Sign in / Sign up

Export Citation Format

Share Document