Biological functions are inherently hierarchical. We plan to investigate the underlying mechanism of biological functions from the single molecular level to the level of supramolecular assemblies, focusing on the mechanism which is characteristic of each level of hierarchy. Our study will be focused primarily on a biological motility system, a typical example of the hierarchical nature of biological functions, starting from interactions between single molecular motors and track polymers (actin-myosin; kinesin-microtubule), to whole ensembles of such interactions (nanomuscle, myofibrils and fibers; cytoskeleton), and on to single cells and whole tissues (the heart). We also aim to develop a technique that will allow the use of the cytoskeleton as a "bionanogauge" that will allow, for example, the monitoring of stress imposed on the cytoskeleton.