NEMATODE SPERM - AMEBOID MOVEMENT WITHOUT ACTIN

Nematodes produce amoeboid sperm that crawl over surfaces in a manner reminiscent of many actin-rich cells. However, These sperm contain no F-actin, and their motility is powered by a dynamic filament system co mposed of polymers of the 14-kDa major sperm protein (MSP). These simp le cells use this unique motility apparatus exclusively for locomotion . Recent studies have capitalized on this feature to explore the key s tructural properties of MSP related to its role in motility and to rec onstitute the motility apparatus both in vivo and in vitro. This revie w discusses how these investigations have laid the foundation for unde rstanding the physical basis of amoeboid movement by identifying the m echanistic properties shared by the MSP-based machinery and the more f amiliar actin-based systems.