Fig. 8. Model of normal and dystrophic costameric patterns. Sarcolemmal basement membrane (bm), plasma membrane (pm), cortical cytoskeleton (cc) and underlying sarcomeres (sm) are shown. Normal (wild-type, wt) basement membrane, although continuous, is condensed into circumferential Z (major) and M (minor) bands and longitudinal (L) striations that correspond to the same pattern elements seen with ß1-integrin and dystroglycan receptors and cytoskeletal vinculin and dystrophin. The basement membrane, receptor and cytoskeletal dy^2J lattice-like patterns become generally effaced while the receptor (dystroglycan, this study) and cytoskeletal (spectrin) (Williams and Bloch, 1999) M and L elements of mdx muscle are lost, with less-pronounced changes in the laminin pattern.