"The role played by actin in clathrin mediated endocytosis has been controversial for a long time," Zenisek said. "We've now shown in live cells that proteins involved in actin polymerization are recruited to sites of membrane scission, and that disturbing actin polymerization with the toxin latrunculin B, a toxin found in Red Sea sponge, drastically reduces the efficiency of membrane scission and affects many aspects of CCP dynamics."