Fascin

Fascin is a 54-58kDa monomeric actin filament bundling protein originally isolated from sea urchin egg but also found in Drosophila, vertebrates including man. Fascin (from the latin for bundle) is spaced at 11nm intervals along the filament. The bundles in cross section are seen to be hexagonally packed this and the longnitudinal spacing is compatible with a model where fascin cross-links at alternating 4 and 5 actins. It does seem likely that it may be most closely related to the fimbrin/plastin group since it is, like them, calcium insensitive, monomeric and close in apparent molecular weight.

Fascin binds b-catenin, a molecule that is not only part of cell-cell adhesion, but is also part of the wnt signalling pathway. It has been proposed that fascin reduces the cytplasmic pool of soluble b-catenin and so would be expected to act as an anti-oncogene.