PROSITE documentation PDOC00568

Vinculin family signatures

Vinculin [1] is a eukaryotic protein that seems to be involved in the attachment of the actin-based microfilaments to the plasma membrane. Vinculin is located at the cytoplasmic side of focal contacts or adhesion plaques. In addition to actin, vinculin interacts with other structural proteins such as talin and α-actinins.

Vinculin is a large protein of 116 Kd (about a 1000 residues). Structurally the protein consists of an acidic N-terminal domain of about 90 Kd separated from a basic C-terminal domain of about 25 Kd by a proline-rich region of about 50 residues. The central part of the N-terminal domain consists of a variable number (3 in vertebrates, 2 in Caenorhabditis elegans) of repeats of a 110 amino acids domain.

Catenins [2] are proteins that associate with the cytoplasmic domain of a variety of cadherins. The association of catenins to cadherins produces a complex which is linked to the actin filament network, and which seems to be of primary importance for cadherins cell-adhesion properties. Three different types of catenins seem to exist: α, β, and γ. α-catenins are proteins of about 100 Kd which are evolutionary related to vinculin. In term of their structure the most significant differences are the absence, in α-catenin, of the repeated domain and of the proline-rich segment.

We developed two signature patterns for this family of proteins. The first pattern is located in the N-terminal section of both vinculin and α-catenins and is part, in vinculin, of a domain that seems to be involved with the interaction with talin. The second pattern is based on a conserved region in the N-terminal part of the repeated domain of vinculin.