Ca ion and the troponin switch.

Muscle contraction as an event manifest by the sliding of myosin filaments along actin filaments was first proposed about fifty years ago by H. Huxley and J. Hanson (Huxley, 2004). This theory built a foundation for muscle research at the molecular level. A decade later the discovery of troponin by Professor S. Ebashi (Ebashi, 1963; Ebashi et al., 1967) highlighted the importance of regulation of muscle contraction and sparked numerous experimental studies of the mysterious protein troponin whose properties are now becoming understood at satisfying resolution.