Conserved Site

Integrin alpha chain, C-terminal cytoplasmic region, conserved site (IPR018184)

Short name: Integrin_alpha_C_CS


Some alpha subunits are cleaved post- translationally to produce a heavy and a light chain linked by a disulphide bond [PMID: 3028640, PMID: 2199285]. Integrin alpha chains share a conserved sequence which is found at the beginning of the cytoplasmic domain, just after the end of the transmembrane region. Within the N-terminal domain of alpha subunits, seven sequence repeats, each of approximately 60 amino acids, have been found [PMID: 3327687]. It has been predicted that these repeats assume the beta-propeller fold. The domains contain seven four-stranded beta-sheets arranged in a torus around a pseudosymmetry axis [PMID: 8990162]. Integrin ligands and a putative Mg2+ ion are predicted to bind to the upper face of the propeller, in a manner analogous to the way in which the trimeric G-protein beta subunit (G beta) (which also has a beta-propeller fold) binds the G protein alpha subunit [PMID: 8990162].

Integrin cytoplasmic domains are normally less than 50 amino acids in length, with the beta-subunit sequences exhibiting greater homology to each other than the alpha-subunit sequences [PMID: 12826403]. This is consistent with current evidence that the beta subunit is the principal site for binding of cytoskeletal and signalling molecules, whereas the alpha subunit has a regulatory role. The first ten residues of the alpha-subunit cytoplasmic domain appear to form an alpha helix that is terminated by a proline residue. The remainder of the domain is highly acidic in nature and this loops back to contact the membrane-proximal lysine anchor residue.

This entry represents the conserved site of the C-terminal integrin alpha chain.

Contributing signatures

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