ß-Adrenergic Stimulation Increases RyR2 Activity via Intracellular Ca2+ and Mg2+ Regulation
Figure 1
ß-adrenergic stimulation of heart phosphorylates RyR2 at S2808 and S2814.
Rat hearts were perfused with buffer alone (control; examples from 2 hearts) or buffer containing 1 µM isoproterenol for 1 min (Iso 1 min; examples from 2 hearts). SR preparations, separated on tris-acetate 3–8% gel, were probed for S2808 and S2814 phosphorylation. SR isolates from control hearts were phosphorylated in vitro by endogenous CaMKII, exogenous PKA or dephosphorylated by exogenous PP1 (Methods). Lanes within each grouping were obtained from the same Western membranes and displayed using identical image intensity and contrast. (A) Representative Western blots probed with pS2808, DepS2808 or pS2814 antibodies and re-probed with anti-RyR2. (B) Relative levels of S2808 phosphorylation and (C) S2814 phosphorylation. Band densities were normalized to RyR2 loading in each lane relative to maximal band densities of PP1 for DepS2808; PKA for pS2808 and CaMKII for pS2814. Data show mean ± sem of 3–6 hearts where number of replicates for each heart are given in Table S1 in File S1 (* p<0.05, ** p<0.01).