Biology Reference
In-Depth Information
15
Role of Villin in the Dynamics of
Actin Microfilaments
Rafika Athman, Sylvie Robine
and
Daniel Louvard
Villin is a tissue specific actin-binding protein, present in intestinal and
proximal kidney brush borders. In vitro, villin has been shown to bundle and
sever F-actin in a calcium-dependent manner. Our previous in vivo data on
villin knock-out mice showed that, while this protein is not necessary for the
bundling of F-actin, it is important for the reorganization of the actin
cytoskeleton elicited by stresses during both physiological and pathological
conditions (Ferrary et al., 1999). These data suggest that villin may be
involved in the actin cytoskeleton remodelling necessary for many cellular
processes requiring cytoskeleton plasticity. Our further studies enabled us to
show that villin is involved in the actin dynamics occurring during different
cellular events. Indeed, we showed that villin expression results in increased
HGF induced cell motility and morphogenesis evaluated by tubulogenesis
assays (Athman et al., in press). We also showed that villin is involved in the
actin remodelling events necessary for the infectious process of Shigella
flexneri in vivo as well as in cell culture models (Athman et al., submitted).
Altogether, we show that villin acts as an enhancer of the actin cytoskeleton
dynamics elicited by HGF stimulation and infection. Our studies thus show
that villin is not only a structural actin-binding protein as shown by its role in
the architecture of the intestinal brush border but also an actin remodelling
protein playing a key role in the regulation of actin dynamics through its
multiple properties.
