Domain

Tetraspanin, EC2 domain (IPR008952)

Short name: Tetraspanin_EC2

Domain relationships

Description

Tetraspanins are a distinct family of proteins, containing four transmembrane domains: a small outer loop (EC1), a larger outer loop (EC2), a small inner loop (IL) and short cytoplasmic tails. They contain characteristic structural features, including 4-6 conserved extracellular cysteine residues, and polar residues within transmembrane domains.

A fundamental role of tetraspanins appears to be organizing other proteins into a network of multimolecular membrane microdomains, sometimes called the `tetraspanin web'. Within this web there are primary complexes in which tetraspanins show robust, specific, and direct lateral associations with other proteins. The strong tendency of tetraspanins to associate with each other probably contributes to the assembly of a network of secondary interactions in which non-tetraspanin proteins are associated with each other via palmitoylated tetraspanins acting as linker proteins. In addition, the association of lipids, such as gangliosides and cholesterol, probably contributes to the assembly of even larger tetraspanin complexes, which have some lipid raft-like properties (e.g. resistance to solubilization in non-ionic detergents). Within the tetraspanin web, tetraspanin proteins can associate not only with integrins and other transmembrane proteins, but also with signalling enzymes such as protein kinase C and phosphatidylinositol-4 kinase. Thus, the tetraspanin web provides a mechanistic framework by which membrane protein signalling can be expanded into a lateral dimension [PMID: 12575999].

This entry represents the EC2 domain from tetraspanins, consisting of 5 helices in an irregular disulphide-linked array which plays a role in form homodimerization.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
SUPERFAMILY