Cytoskeleton: Getting to the point with myosin VI

The rather inappropriately named ‘unconventional’ myosins — unconventional in comparison with the betterknown muscle myosin — are a superfamily of actin-based motor proteins, characterized by a conserved motor domain that generates ATP-dependent movement along actin [1]. Unconventional myosins have been found to be responsible for numerous cellular movements, such as cytokinesis, pseudopod extension, vesicle transport and the targeting of mRNAs, to name but a few [1,2]. Few unconventional myosins have been biochemically analyzed in detail, however, because of the difficulties in isolating sufficient quantities of the protein, but improvements in expression technology have now made it possible to begin to systematically study many members of the myosin superfamily. The approach is already providing important new insights, one exciting recent example of which is the discovery that myosin VI moves in a direction opposite to all other known myosins [3].