Figure 7.

S100A1 interacts with RyR2 and reduces the SR Ca²⁺ leak in failing myocardium. (A) Nomarski image of an NFC-AdS100A1. Immunolabeling of (B) S100A1 (blue) and (C) RyR2 (red) in the same cell. (D) Overlay of B and C depicts colocalization of S100A1 and RyR2 (violet). Scale bar: 20 μm. Inset magnification, ×3. (E) Ca²⁺-dependent coimmunoprecipitation of RyR2 (green) and S100A1 (red). Control experiments were carried out with A/G-Sepharose beads only. (F and G) Typical tracings of the time course (F) and averaged values (%) (G) of the SR Ca²⁺ leak in nonfailing and failing myocardium and AdGFP- and AdS100A1-transfected failing myocardium. Arrow indicates addition of thapsigargin (+TG; 1 μM) (n = 4). *P < 0.01, NF vs. F and F-AdGFP; **P < 0.01, F-AdS100A1 vs. F and F-AdGFP; P = NS, NF vs. F-AdS100A1. Data are presented as mean ± SEM.