Villin is a major actin-bundling protein in the brush border of epithelial cells. In this study we
demonstrate for the first time that villin can bundle actin filaments using a single F-actin
binding site, because it has the ability to self-associate. Using fluorescence resonance
energy transfer, we demonstrate villin self-association in living cells in microvilli and in
growth factor-stimulated cells in membrane ruffles and lamellipodia. Using sucrose density
gradient, size-exclusion chromatography, and matrix-assisted laser desorption ionization …