LC3 and p62 accumulate in IBMPFD muscle tissue. (A and B) Immunoblot of 9-mo-old quadriceps muscle lysates from control (cont) or VCP-WT, -RH9, or -RH12 mutant transgenic lines with p62 (A) or LC3 (B) antibodies. Note the increase in p62 and LC3II isoforms in mutant animals. Densitometric quantification is from more than six 9-mo-old animals/group. LC3 and p62 levels are normalized to loading control. Error bars represent the standard error from six independent experiments. **, P < 0.001. AU, arbitrary unit. (C) p62 immunostaining of tibialis anterior (TA) or quadriceps (Quad) muscle from 9-mo-old control, VCP-WT, or one of two VCP-RH transgenic lines (RH9 or RH12). Note accumulations of p62 in the middle of myofibers or along subsarcolemmal regions. (D) Histochemistry and immunohistochemistry of quadriceps muscle from VCP-RH–expressing transgenic mice. Hematoxylin and eosin (H&E) staining of a 15-mo-old animal with an RV, p62 immunostaining of an RV from a 12-mo-old animal, LC3 immunostaining of an RV, and subsarcolemmal accumulations of LC3 from a 12-mo-old animal. The bracket highlights one LC3-positive myofiber. A single muscle fiber is outlined in white. (C and D) Arrows denote vacuoles or accumulations of p62 or LC3. Bars, 30 µm.