CaMKII-dependent phosphorylation of RyR2 promotes targetable pathological RyR2 conformational shift.
Diastolic calcium (Ca) leak via cardiac ryanodine receptors (RyR2) can cause arrhythmias and heart failure (HF). Ca/calmodulin (CaM)-dependent kinase II (CaMKII) is upregulated and more active in HF, promoting RyR2-mediated Ca leak by RyR2-Ser2814 phosphorylation. Here, we tested a mechanistic hypothesis that RyR2 phosphorylation by CaMKII increases Ca leak by promoting a pathological RyR2 conformation with reduced CaM affinity. Acute CaMKII activation in wild-type RyR2, and phosphomimetic RyR2-S2814D (vs. non-phosphorylatable RyR2-S2814A) knock-in mouse myocytes increased SR Ca leak, reduced CaM-RyR2 affinity, and caused a pathological shift in RyR2 conformation (detected via increased access of the RyR2 structural peptide DPc10). This same trio of effects was seen in myocytes from rabbits with pressure/volume-overload induced HF. Excess CaM quieted leak and restored control conformation, consistent with negative allosteric coupling between CaM affinity and DPc10 accessible conformation. Dantrolene (DAN) also restored CaM affinity, reduced DPc10 access, and suppressed RyR2-mediated Ca leak and ventricular tachycardia in RyR2-S2814D mice. We propose that a common pathological RyR2 conformational state (low CaM affinity, high DPc10 access, and elevated leak) may be caused by CaMKII-dependent phosphorylation, oxidation, and HF. Moreover, DAN (or excess CaM) can shift this pathological gating state back to the normal physiological conformation, a potentially important therapeutic approach.
Department of Pharmacology University of California, Davis, CA.
Hitoshi
H
Uchinoumi
Department of Pharmacology University of California, Davis, CA.
Yi
Y
Yang
Department of Pharmacology University of California, Davis, CA.|Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi.
Tetsuro
T
Oda
Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.|Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA.
Na
N
Li
Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.|Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA.|Integrative Molecular & Biomedical Sciences Program, Baylor College of Medicine, Houston, TX, USA.
Katherina M
KM
Alsina
Department of Pharmacology University of California, Davis, CA.
Jose L
JL
Puglisi
Department of Pharmacology University of California, Davis, CA.
Ye
Y
Chen-Izu
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN.
Razvan L
RL
Cornea
Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.|Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA.|Department of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA.|Pediatrics, Baylor College of Medicine, Houston, TX, USA.
Xander H T
XHT
Wehrens
Department of Pharmacology University of California, Davis, CA.
Donald M
DM
Bers
D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D003620:Dantrolene / Q000494:pharmacology; D004195:Disease Models, Animal; D006333:Heart Failure / Q000378:metabolism / Q000473:pathology; D015640:Ion Channel Gating; D051379:Mice; D032383:Myocytes, Cardiac / Q000378:metabolism; D010539:Permeability; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D011817:Rabbits; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry* / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D022021:Tacrolimus Binding Proteins / Q000378:metabolism
D002147:Calmodulin; D019837:Ryanodine Receptor Calcium Release Channel; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D022021:Tacrolimus Binding Proteins; C403484:tacrolimus binding protein 1B; D003620:Dantrolene; D002118:Calcium
Calcium/calmodulin-dependent protein kinase II; Calmodulin; Dantrolene; Fluorescence resonance energy transfer; Ryanodine receptor