Which of the following is an anchoring protein?

Some additional structural proteins that are impoant in skeletal muscle function include actinin, titin, and desmin. Actinin binds actin to the Z lines. Titin, the largest known protein (with a molecular mass near 3,000,000 Da), connects the Z lines to the M lines and provides scaffolding for the sarcomere. It contains two kinds of folded domains that provide muscle with its elasticity. At first, when the muscle is stretched there is relatively little resistance as the domains unfold, but with fuher stretch, there is a rapid increase in resistance that protects the structure of the sarcomere. Desmin adds structure to the Z lines in pa by binding the Z lines to the plasma membrane. Ref: Ganong 25th ed, p 101