SERCA1a protein level is altered in muscles from Smn-/-; SMN2 mice. (A) Whole muscle lysate was collected from P2, P5, P9, and P21 wild type mice and immunoblot analysis was performed to assess SERCA1a protein levels. SERCA1a levels increase over time and peak at P9 (N = 3). (B) Immunoblot with quantification showing a decrease in SERCA1a, but not calsequestrin, in hindlimb muscle from P5 Smn-/-;SMN2 mice compared with control (N = 3). (C) Immunoblots were performed on muscle lysates collected from experimentally denervated (DEN) and sham operated (SHAM) muscle. No change in SERCA1a levels was observed. N = 3, *, P < 0.05.