Dystrophin is localized to the plasma membrane of human skeletal muscle fibers by electron-microscopic cytochemical study.

Electron-microscopic immunoperoxidase technique revealed plasmalemmal localization of dystrophin in microscopically normal human skeletal muscle fibers obtained from nine routine diagnostic muscle biopsies. There was no evidence of periodicity of the immunoreactive product nor was there any evidence of immunostaining in any organelle besides the plasma membrane. Dystrophin appears to be a cytoskeletal protein associated with the plasmalemma. Its function is presumed to be the maintenance of the mechanical stability of the surface membrane so that it can withstand the normal contraction-induced stresses without disruption.