α/β CaMKII co-overexpression in relation to MHC and SERCA2 expression. A-C) Microscopic field of α/β CaMKII-transfected SOL muscle stained for CaMKII (A, red), fast MyHCII (B, green) and slow MHCI (C, blue). Corresponding areas are circled. D, E) Microscopic field of an α/β CaMKII-transfected SOL muscle after staining for CaMKII (red, D) and SERCA2 (yellow, E). F) Bar graph visualizing the mean + SE of SERCA2 levels in transfected (Tf, n = 276) and non-transfected (NTf, n = 221) muscle fibers. *, p ≤0.001.