In skeletal muscle, actin is bound to Z line by

Actinin binds actin to the Z lines. Titin connects the Z lines to the M lines and provides scaffolding for the sarcomere. Desmin adds structure to the Z lines in pa by binding the Z lines to the plasma membrane. Tropomyosin molecules are long filaments located in the groove between the two chains in the actin (Figure 5-3). (Ref: Ganong's review of medical physiology 23rd Edition page no.96)