α-Actinin Is a Component of the Z-Filament, a Structural Backbone of Skeletal Muscle Z-Disks1

摘要: The relationship between the ultrastructure and protein components of Z-disks was studied using psoas muscles rabbit breast chicken. Glycerinated fiber bundles these were treated with a solution containing 0.1 mM Ca2+ to induce structural weakening non-enzymatically. During treatment, clear geometrical configurations Z-filaments could be observed along removal amorphous matrix under an electron microscope. Even after prolonged treatment for 14 d in which all entirely weakened, entangled left original region disks. Immunoelectron microscopic observations showed that antibodies against alpha-actinin bound Z-filaments, forming dense lines at position Z-disks. On SDS-PAGE Z-disk substances, remained unchanged Mr 75,000 55,000 proteins removed during Ca2+-treatment. We therefore conclude is component composed least proteins.