Remodelling of the actin cytoskeleton is required for the dynamic cell shape changes that underlie cell migration, a pivotal developmental process. But what are the key regulators of actin reorganisation during cell migration?On , Zanet and colleagues reveal that the migration of a subpopulation of motile blood cells(macrophage-like plasmatocytes) during Drosophila embryogenesis involves the actin-bundling protein Fascin. They show that plasmatocytes express high levels of Fascin and that Fascin is required for their polarisation and migration during development and during an inflammatory response to epithelial wounding. Fascin, they report, localises to, and is essential for the assembly of, actin-rich microspikes that extend beyond the leading edge of the migrating plasmatocytes. Finally, they show that Fascin activity is regulated post-translationally by phosphorylation in a tissue-specific manner. In humans, increased Fascin expression is correlated with the invasiveness of various tumours. Thus, these unique insights into Fascin function and regulation during normal development might help to explain how fascin misregulation contributes to cancer progression.
