Myosin Structure and Function

There has been an explosion of interest in molecular motors in the last decade, and it is clear that both the actin-based motors and the microtubule-based motors constitute large families, members of which carry out distinct functions in the cell (Vale 1992; Goldstein 1993; Mooseker 1993). This last decade has witnessed an increased effort in genetic and molecular genetic approaches that have revealed the molecular basis of a number of forms of cell movement and changes in cell shape (Vale 1992; Goldstein 1993; Spudich 1994). In addition, methods have been developed for measuring the movement of purified molecular motors in vitro, and these methods have allowed the definition of critical parameters of molecular motor function (for review, see Spudich 1994). Here we focus on the first-identified and best-characterized member of the molecular motor superfamily, the conventional myosin molecule, which was first discovered in muscle in the 19th century. This conventional...