An actin binding protein found at the leading edge of locomoting cells and the tips of hair cell villi.

References:-

Bearer, E.L. and Abraham, M.T. "2E4 (kaptin): a novel actin-associated protein from human blood platelets found in lamellipodia and the tips of the stereocilia of the inner ear. Eur.J.Cell Biol. 78, 117-126.