This family consists of several eukaryotic fascin or singed proteins. 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 [1]. Dictyostelium hisactophilin, another actin-binding protein, is a submembranous pH sensor that signals slight changes of the H+ concentration to actin by inducing actin polymerisation and binding to microfilaments only at pH values below seven [1]. Members of this family are histidine rich, typically contain the repeated motif of HHXH [3].

1: Fascins, and their roles in cell structure and function. Kureishy N, Sapountzi V, Prag S, Anilkumar N, Adams JC; Bioessays 2002;24:350-361. PMID:11948621

2: Fascin, an echinoid actin-bundling protein, is a homolog of the Drosophila singed gene product. Bryan J, Edwards R, Matsudaira P, Otto J, Wulfkuhle J; Proc Natl Acad Sci U S A 1993;90:9115-9119. PMID:8415664

3: Structure of hisactophilin is similar to interleukin-1 beta and fibroblast growth factor. Habazettl J, Gondol D, Wiltscheck R, Otlewski J, Schleicher M, Holak TA; Nature 1992;359:855-858. PMID:1436061