The actin cytoskeleton is involved in the regulation of cell
morphology and migration. Wiskott-Aldrich Syndrome proteins
(WASPs) play an important role in controlling actin
polymerization by activating the Arp2/3 complex. The present
study investigated the roles of WasC, one of the 3 WASPs
in Dictyostelium, in cellular processes. Cells lacking WasC
displayed strong cell adhesion and approximately 1.5-fold
increase in F-actin levels as compared to the wild-type cells.
Loss of wasC caused defects in phagocytosis and decreased
the migration speed in chemoattractant-mediated cell migration
but did not affect directionality. WasC was localized to the
protruding region in migrating cells and, transiently and rapidly
translocated to the cell cortex in response to chemoattractant
stimulation, in an F-actin dependent manner. Our
results
suggest that WasC is involved in cell adhesion and
migration by regulating F-actin polymerization at the leading
edge of migrating cells, probably as a negative regulator.
The increased strength of adhesion in wasC null cells is likely
to decrease the migration speed but not the directionality.