Villin-1

Villin-1 contains multiple gelsolin-like domains capped by a small (8.5 kDa) "headpiece" at the C-terminus consisting of a fast and independently folding three-helix bundle that is stabilized by hydrophobic interactions.

[2] The headpiece domain is a commonly studied protein in molecular dynamics due to its small size and fast folding kinetics and short primary sequence.

[4] Villin is found localized in the microvilli of the brush border of the epithelium lining of the gut and renal tubules in vertebrates.

However, knockout mice appear to show ultra-structurally normal microvilli reminding us that the function of villin is not definitively known; it may play a role in cell plasticity through F-actin severing.

Villin-4 C-terminal construct VHP76 in Arabidopsis thaliana has been shown to exhibit higher affinity for F-actin in increasing concentrations of Ca2+, which further confirms the function of villin.

Currently, it is theorized the regulation of plant villins are caused by degradation via the binding protein auxin, which targets the headpiece domain (VHP).