Polarized epithelial cells display a cell surface organization well ad
apted to their specialized functions in transports and exchanges with
the external ''milieu''. The numerous microvilli that cover the apical
plasma membrane are supported by bundles of actin microfilaments and
associated actin binding proteins. Three independant experimental appr
oaches have been used to unravel the function(s) of villin: a) overexp
ression of the villin gene; b) inhibition of villin production iwth a
villin antisens RNA; c) disruption of the villin gene by homologeous r
ecombination, The role of ezrine, a protein able to interact both with
components of the plasma membrane and with actin microfilaments, in c
ellular morphogenesis and the signal transduction cascade elicitatd by
the scatter factor (HGF) and its receptor, has also been investigated
with molecular cell biology approaches.