The fascins are a structurally unique and evolutionarily conserved group of actin cross-linking proteins. Fascins function in the organisation of two major forms of actin-based structures: dynamic, cortical cell protrusions and cytoplasmic microfilament bundles. The cortical structures, which include filopodia, spikes, lamellipodial ribs, oocyte microvilli and the dendrites of dendritic cells, have roles in cell-matrix adhesion, cell interactions and cell migration, whereas the cytoplasmic actin bundles appear to participate in cell architecture. We discuss the current understanding of the cellular mechanisms that regulate the binding of fascin to actin and how these processes contribute to the organisation or disassembly of cell protrusions. Although the in vivo roles of fascin have been studied principally in Drosophila, several human diseases are associated with inherited or acquired alterations in the expression of fascins. Strategies to modulate fascin-containing protrusions and thereby cell adhesive and migratory behaviour could have potential for therapeutic intervention in these conditions. The supplementary material referred to in this section can be found at http://www.interscience.wiley.com/jpages/0265-9247/suppmat/2002/v24.350.html

Abbreviations used in this paper: crm1, chromosome maintenance region 1; CTLH, C-terminal to LisH; DD, discoidin-like domain; FN, fi bronectin; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; LIS1, lissencephaly-1; LisH, LIS1 homology; NES, nuclear export sequence; shRNA, short hairpin RNA; SMART, simple modular architecture research tool; TSP-1, thrombospondin-1.The online version of this paper contains supplemental material.