The calcium ions released into the cytosol during excitation of skeletal muscle bind to

Bind to the protein complex troponin.

Explanation:

Excitation of skeletal muscle caused by the calcium ions. During excitation of skeletal muscle, after calcium ions released into the cytosol, they bind to the protein complex known as troponin and causing substitutions in the protein complex.

These alterations permit protein to push out from the myosin-binding sites on the actin filament.