Please inhibit responsibly: Natural and synthetic actin toxins as useful tools in cell biology.

The actin cytoskeleton drives many critical cell functions, including motility, division, and vesicular trafficking. To fulfill these functions, actin networks are dynamic and tightly regulated by dozens of proteins that cause actin to assemble and disassemble at the proper time and place. Given the importance of actin to a cell's biology, it is not surprising that some organisms produce toxins that target actin dynamics to incapacitate prey, win turf wars, or as a defense against predation. For decades, cell biologists have leveraged these toxins and synthesized new ones to cause defects in the structure and function of the actin cytoskeleton. Here, we provide an overview of commonly used actin inhibitors and their origins, as well as best practices for their use in biological studies.