Figure 3. BAG3 downregulation reduces contraction and [Ca²⁺]_i transient amplitudes in myocytes stimulated with isoproterenol.

(A). Adult mouse hearts were injected with Adv-shRNA-BAG3 + Adv-GFP or Adv-GFP alone, and tissues were harvested after 10 days and blotted for BAG3, Na⁺/Ca²⁺ exchanger (NCX1), α1c-subunit of L-type Ca²⁺ channel (Ca_v1.2), sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA2), cardiac ryanodine receptor phosphorylated at serine²⁸⁰⁸ and at serine²⁸¹⁴ (p²⁸⁰⁸RyR2 and p²⁸¹⁴RyR2), total RyR2, α1- and α-2subunits of Na⁺-K⁺-ATPase, and calsequestrin (CLSQ) was used as loading control. Quantitative results are shown in Table 1. (B & C). Representative traces of [Ca²⁺]_i transients (B) and cell shortening (C) in GFP and shBAG3 myocytes, before and after addition of isoproterenol (1 μM). Composite results are shown in Table 2.