Actin-Binding Drugs: An Elegant Tool to Dissect Subcellular Processes in Endothelial and Cancer Cells

Until a decade or so ago there were only a few agents available that interfered with cellular activities by binding to actin. In fact, most of our initial knowledge concerning the involvement of actin in basic cellular processes was based on the extensive use of the mold metabolites cytochalasins. However, the actin-binding activities and cellular effects of cytochalasins are complex and difficult to interpret (Cooper 1987; Sampath and Pollard 1991), so that the functions and dynamics of the actin cytoskeleton in various organisms remained elusive. Another widely used class of actin-binding drugs, the mushroom-derived phallotoxins, stabilizes actin filaments and promotes actin polymerization (Cooper 1987; Sampath and Pollard 1991), but they do not enter most cell types and are predominantly used as fluorescent derivatives to visualize actin filaments in fixed cells.