Analysis of calstabin2 (FKBP12.6)-ryanodine receptor interactions: rescue of heart failure by calstabin2 in mice.
The ryanodine receptor (RyR)/calcium-release channel on the sarcoplasmic reticulum mediates intracellular calcium release required for striated muscle contraction. RyR2, the predominant isoform in cardiac myocytes, comprises a macromolecular complex that includes calstabin2 (FKBP12.6). Calstabin2, an 11.8-kDa cis-trans peptidyl-prolyl isomerase (apparent molecular mass 12.6 kDa), stabilizes the closed state of the RyR2 channel, but the mechanism by which it achieves this regulation is not fully understood. Protein kinase A (PKA) phosphorylation of RyR2 decreases the affinity of calstabin2 for the RyR2 channel complex. In the present study we identified key aspartic acid residues on calstabin2 that are involved in binding to RyR2 and likely play a role in PKA phosphorylation-induced dissociation of calstabin2 from RyR2. We show that a mutant calstabin2 in which a key negatively charged residue (Asp-37) has been neutralized binds to a mutant RyR2 channel that mimics constitutively PKA-phosphorylated RyR2 (RyR2-S2808D). Furthermore, using wild-type and genetically altered murine models of heart failure induced by myocardial infarction, we show that manipulating the stoichiometry between calstabin2 and RyR2 can restore normal cardiac function in vivo.
Huang
Fannie
F
Clyde and Helen Wu Center for Molecular Cardiology, Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
Shan
Jian
J
Reiken
Steven
S
Wehrens
Xander H T
XH
Marks
Andrew R
AR
D000818:Animals; D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism; D002384:Catalysis; D004195:Disease Models, Animal; D004594:Electrophysiology; D005786:Gene Expression Regulation; D051379:Mice; D008822:Mice, Transgenic; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D009203:Myocardial Infarction / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000235:genetics / Q000378:metabolism; D055672:Static Electricity; D040681:Structural Homology, Protein; D022061:Tacrolimus Binding Protein 1A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D022021:Tacrolimus Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D001224:Aspartic Acid; D011494:Protein Kinases; D019837:Ryanodine Receptor Calcium Release Channel; D012694:Serine; D022061:Tacrolimus Binding Protein 1A; D022021:Tacrolimus Binding Proteins; C509259:FKBP1B protein, mouse