InterPro : IPR000413

Name  Integrin alpha chain Short Name  Integrin_alpha
Type  Family Description  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 [, ]. The integrin receptors are composed of alpha and beta subunit heterodimers. 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 []. There are at least 18 types of alpha and 8 types of beta subunits recognised in humans []. Each alpha subunit tends to associate only with one type of beta subunit, but there are exceptions to this rule []. 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.Some alpha subunits are cleaved post-translationally to produce a heavy and a light chain linked by a disulphidebond [, ]. Integrin alpha chains share a conserved sequence which is found atthe beginning of the cytoplasmic domain, just after the end of thetransmembrane region. Within the N-terminal domain of alpha subunits, seven sequence repeats, eachof approximately 60 amino acids, have been found []. 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[]. Integrin ligands and a putative Mg2+ion are predicted to bind to theupper face of the propeller, in a manner analogous to the way in which thetrimeric G-protein beta subunit (G beta) (which also has a beta-propellerfold) binds the G protein alpha subunit [].Integrin cytoplasmic domains are normally less than 50 amino acids in length, with the beta-subunit sequencesexhibiting greater homology to each other than the alpha-subunit sequences []. This is consistent withcurrent evidence that the beta subunit is the principal site for binding of cytoskeletal and signallingmolecules, whereas the alpha subunit has a regulatory role. The first ten residues of thealpha-subunit cytoplasmic domain appear to form an alpha helix that is terminated by a proline residue. Theremainder of the domain is highly acidic in nature and this loops back to contact themembrane-proximal lysine anchor residue.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

4 Contains

Id Name Short Name Type
IPR013649 Integrin alpha-2 Integrin_alpha-2 Domain
IPR013517 FG-GAP repeat FG-GAP Repeat
IPR013519 Integrin alpha beta-propellor Int_alpha_beta-p Repeat
IPR018184 Integrin alpha chain, C-terminal cytoplasmic region, conserved site Integrin_alpha_C_CS Conserved_site

0 Found In

0 Parent Features

10 Publications

First Author Title Year Journal Volume Pages
Hynes RO Integrins: a family of cell surface receptors. 1987 Cell 48 549-54
Albelda SM Integrins and other cell adhesion molecules. 1990 FASEB J 4 2868-80
Springer TA Folding of the N-terminal, ligand-binding region of integrin alpha-subunits into a beta-propeller domain. 1997 Proc Natl Acad Sci U S A 94 65-72
Corbi AL cDNA cloning and complete primary structure of the alpha subunit of a leukocyte adhesion glycoprotein, p150,95. 1987 EMBO J 6 4023-8
Hynes RO Integrins: bidirectional, allosteric signaling machines. 2002 Cell 110 673-87
Humphries MJ Integrin structure: heady advances in ligand binding, but activation still makes the knees wobble. 2003 Trends Biochem Sci 28 313-20
Demetriou MC Integrin clipping: a novel adhesion switch? 2004 J Cell Biochem 91 26-35
Cheresh DA A novel vitronectin receptor integrin (alpha v beta x) is responsible for distinct adhesive properties of carcinoma cells. 1989 Cell 57 59-69
Bökel C Integrins in development: moving on, responding to, and sticking to the extracellular matrix. 2002 Dev Cell 3 311-21
Arnaout MA Integrin structure: new twists and turns in dynamic cell adhesion. 2002 Immunol Rev 186 125-40

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)