SMART accession number:SM01242
Description: This is the beta tail domain of the Integrin protein. Integrins are receptors which are involved in cell-cell and cell-extracellular matrix interactions.
Interpro abstract (IPR012896):

Integrins are the major metazoan receptors for cell adhesion to extracellular matrix proteins and, in vertebrates, also play important roles in certain cell-cell adhesions, make transmembrane connections to the cytoskeleton and activate many intracellular signalling pathways [ (PUBMED:12297042) (PUBMED:12361595) ]. An integrin receptor is a heterodimer composed of alpha and beta subunits. Each subunit crosses the membrane once, with most of the polypeptide residing in the extracellular space, and has two short cytoplasmic domains. Some members of this family have EGF repeats at the C terminus and also have a vWA domain inserted within the integrin domain at the N terminus.

Most integrins recognise relatively short peptide motifs, and in general require an acidic amino acid to be present. Ligand specificity depends upon both the alpha and beta subunits [ (PUBMED:12234368) ]. There are at least 18 types of alpha and 8 types of beta subunits recognised in humans [ (PUBMED:14689578) ]. Each alpha subunit tends to associate only with one type of beta subunit, but there are exceptions to this rule [ (PUBMED:2467745) ]. Each association of alpha and beta subunits has its own binding specificity and signalling properties. Many integrins require activation on the cell surface before they can bind ligands. Integrins frequently intercommunicate, and binding at one integrin receptor activate or inhibit another.

This entry represents the tail domain of the integrin beta subunit. It forms a four-stranded beta-sheet that contains parallel and antiparallel strands and faces an alpha helix found at the N terminus of this domain [ (PUBMED:11546839) ]. Interactions between the alpha-helix and the beta-sheet are mostly hydrophobic and involve a disulphide bond. The rear of the beta sheet is covered with a long A-B loop.

Family alignment:
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There are 3207 Integrin_B_tail domains in 3193 proteins in SMART's nrdb database.

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