The correct answer is Troponin because it contains a specific subunit, troponin C, that binds calcium ions during skeletal muscle contraction. This binding induces a conformational change that moves tropomyosin away from actin's myosin-binding sites, allowing muscle contraction to proceed. Without calcium binding to troponin, muscle contraction cannot be initiated, making troponin essential for the regulation of skeletal muscle activity. This mechanism is critical for proper muscle function and is a key target in understanding muscle-related diseases and surgical muscle manipulations.

Reference: Guyton and Hall Textbook of Medical Physiology, Arthur C. Guyton, 13th Edition.