Figure 4. Expression of dystrophin–glycoprotein complex and integrin complex proteins in aged muscle membranes.

One hundred micrograms of total hindlimb muscle membrane protein preparations from three young (12 month) and three very old rats (34–35 months) was analysed by SDS-PAGE and Western blotting (A) and quantified by densitometry (B) *P < 0.05 by Student's t test, data are means ±s.e.m.C and D, mislocalization of dysferlin and no upregulation of utrophin in aged muscle. While expression levels of dysferlin in membrane fractions is normal by Western blotting (C), immunolocalization of dysferlin (D) shows redistribution of dysferlin expression into cytoplasmic membrane compartments. E, no upregulation of utrophin was observed in aged muscle, although full length utrophin protein was detected in a positive control sample from neonatal muscle.