Villin
| villin 1 | |
|---|---|
| Identifiers | |
| Symbol | VIL1 |
| Alt. symbols | VIL |
| Entrez | 7429 |
| HUGO | 12690 |
| OMIM | 193040 |
| RefSeq | NM_007127 |
| UniProt | P09327 |
| Other data | |
| Locus | Chr. 2 q35-q36 |
| villin 2 (ezrin) | |
|---|---|
| Identifiers | |
| Symbol | VIL2 |
| Entrez | 7430 |
| HUGO | 12691 |
| OMIM | 123900 |
| RefSeq | NM_003379 |
| UniProt | P15311 |
| Other data | |
| Locus | Chr. 6 q22-q27 |
Villin is a 92.5 kDa tissue-specific actin-binding protein associated with the actin core bundle of the brush border. Villin 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. The headpiece domain is a commonly studied protein in molecular dynamics due to its small size and fast folding kinetics and short primary sequence.
Villin is made up of seven domains, six homologous domains make up the N-terminal core and the remaining domain makes up the C-terminal cap. Villin contains three phosphatidylinositol 4,5-biphosphate (PIP2) binding sites, one of which is located at the head piece and the other two in the core. The core domain is approximately 150 amino acid residues grouped in six repeats. On this core is an 87 residue, hydrophobic, C-terminal headpiece The headpiece (HP67) is made up of a compact, 70 amino acid folded protein at the C-terminus. This headpiece contains an F-actin binding domain. Residues K38, E39, K65, 70-73:KKEK, G74, L75 and F76 surround a hydrophobic core and are believed to be involved in the binding of F-actin to villin. Residues E39 and K70 form a salt bridge buried within the headpiece which serves to connect N and C terminals. This salt bridge may also orient and fix the C-terminal residues involved in F-actin binding as in the absence of this salt bridge no binding occurs. A hydrophobic “cap” is formed by residue W64 side chains, which is completely conserved throughout the villin family. Below this cap is a crown of alternative positive and negative charged localities. Villin can undergo post-translational modifications like tyrosine phosphorylation. Villin has the ability to dimerize and the dimerization site is located at the amino end of the protein.
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Wikipedia