fimbrin is present in several distinct structures in different cell types, including intestinal microvilli, hair cell stereocilia and fibroblast filopodia. it is usually associated with polarized actin filaments in membrane ruffles, filopodia, stereocilia and adhesion plaques. sequence homology and biochemical properties show that fimbrin is highly conserved from yeast to humans. yeast mutants lacking fimbrin are defective in morphogenesis and endocytosis.