Mutation and dysregulation of the cardiac ryanodine receptor (RyR2) or sarcoplasmic reticulum (SR) calcium release channel contributes directly to catecholaminergic polymorphic ventricular tachycardia (CPVT) and heart failure (HF) in humans. Affected RyRs are more active than normal, leaking Ca from the SR during diastole causing arrhythmias and dysfunction. FKBP12.6 and calmodulin (CaM) are proteins that bind tightly with and may stabilize RyR2. We have developed novel quantitative methods to assess (in adult cardiac myocytes) how FKBP, CaM and other peptides bind to and modulate RyR2 gating, and are structurally positioned on the myocyte RyR2. While FKBP12.6 binds RyR2 with high affinity, it is not a critical RyR2 regulator. Here we examine how CaM binding and altered domain-domain interaction in RyR2 are involved in disease-related RyR2 dysfunction, using fluorescent tagged proteins and novel targeted sensors in adult ventricular myocyte confocal imaging to address 4 aims. We will: 1) Test whether HF-related RyR alterations decrease CaM binding and increase the access of the structural unzipping peptide DPc10. 2) Test whether known RyR inhibitors work on pathological RyR2 by altering FKBP12.6, CaM or DPc10 binding. 3) Measure Cleft [Ca] using novel targeted Ca sensors. 4) Enhance RyR2 structural model by mapping sites of S100A1, CaMKII, IPTx and Sorcin. This is a highly collaborative project between two groups with shared interests in cardiac calcium regulation in HF and arrhythmias and with complementary technical expertise in physiology, pharmacology, biochemistry, molecular biology, fluorescence spectroscopy and confocal imaging. This will greatly enhance our understanding of RyR2 structure and function in cardiac myocytes in health and disease and provide novel strategies for the development of therapeutics for pathologically modulated RyR2 in the heart.
Heart failure and arrhythmias are major human health issues, afflicting millions of Americans. It has become clear that leak of calcium from the sarcoplasmic reticulum within the cardiac myocyte between normal heart beats contributes importantly to both of these major cardiac problems. Here we will elucidate the structural and functional problem at the molecular level and develop novel therapeutic strategies.
|Oda, Tetsuro; Yamamoto, Takeshi; Kato, Takayoshi et al. (2018) Nuclear translocation of calmodulin in pathological cardiac hypertrophy originates from ryanodine receptor bound calmodulin. J Mol Cell Cardiol 125:87-97|
|Hegyi, Bence; Bossuyt, Julie; Griffiths, Leigh G et al. (2018) Complex electrophysiological remodeling in postinfarction ischemic heart failure. Proc Natl Acad Sci U S A 115:E3036-E3044|
|Liu, Miao; Hoskins, Amanda; Verma, Nirmal et al. (2018) Amylin and diabetic cardiomyopathy - amylin-induced sarcolemmal Ca2+ leak is independent of diabetic remodeling of myocardium. Biochim Biophys Acta Mol Basis Dis 1864:1923-1930|
|Stroik, Daniel R; Yuen, Samantha L; Janicek, Kevyn A et al. (2018) Targeting protein-protein interactions for therapeutic discovery via FRET-based high-throughput screening in living cells. Sci Rep 8:12560|
|Galice, Samuel; Xie, Yuanfang; Yang, Yi et al. (2018) Size Matters: Ryanodine Receptor Cluster Size Affects Arrhythmogenic Sarcoplasmic Reticulum Calcium Release. J Am Heart Assoc 7:|
|Hegyi, Bence; Bossuyt, Julie; Ginsburg, Kenneth S et al. (2018) Altered Repolarization Reserve in Failing Rabbit Ventricular Myocytes: Calcium and ?-Adrenergic Effects on Delayed- and Inward-Rectifier Potassium Currents. Circ Arrhythm Electrophysiol 11:e005852|
|Yan, Jiajie; Zhao, Weiwei; Thomson, Justin K et al. (2018) Stress Signaling JNK2 Crosstalk With CaMKII Underlies Enhanced Atrial Arrhythmogenesis. Circ Res 122:821-835|
|Rebbeck, Robyn T; Essawy, Maram M; Nitu, Florentin R et al. (2017) High-Throughput Screens to Discover Small-Molecule Modulators of Ryanodine Receptor Calcium Release Channels. SLAS Discov 22:176-186|
|Bartos, Daniel C; Morotti, Stefano; Ginsburg, Kenneth S et al. (2017) Quantitative analysis of the Ca2+ -dependent regulation of delayed rectifier K+ current IKs in rabbit ventricular myocytes. J Physiol 595:2253-2268|
|Sato, Daisuke; Clancy, Colleen E; Bers, Donald M (2017) Dynamics of sodium current mediated early afterdepolarizations. Heliyon 3:e00388|
Showing the most recent 10 out of 46 publications