Integrins subunit combinations

Several families of integral proteins in the plasma membrane provide specific points of attachment between cells, or between a cell and extracellular matrix proteins. Integrins are heterodimeric proteins (two unlike subunits, a and /3) anchored to the plasma membrane by a single hydrophobic transmembrane helix in each subunit (Fig. 11-22 see also Fig. 7-30). The large extracellular domains of the a and /3 subunits combine to form a specific binding site for extracellular proteins... 

Integrins themselves are found on nearly all cells and mediate several physiological responses, such as cell-cell and cell-matrix interactions. Three families of integrins, each family with a common beta subunit in combination with distinct alpha subunits, have been recognized. The beta 1 family, also called very late lymphocyte-activation antigen or VLA, has receptors mediating extracellular matrix interactions with molecules such as collagen, laminin, and fibronectin. Naturally, platelets contain many of the receptors of the beta 1 family. 

The structure of the integrin family has been deduced largely from the cDNA sequences of the cloned genes. All integrins comprise a- and fl-subunits, and the ligand binding that occurs at the binding site comprises an interaction between the two subunits. The a-subunits can combine with dif-... 

Integrins. The integrin family has been identified as excellent candidates for the development of target specific cancer therapies.29 Integrins are heterodimeric glycoproteins that consist of a and P subunits, which combine to form the various types of integrins. Currently, 18 a subunits, 8 P subunits, and approximately 22 different integrins have been identified.29,30... 

A functional integrin is a heterodimeric protein complex consisting of an a and a P subunit. So far, the mammalian integrin family consists of 8 P subunits and 18 a subunits, which are known to assemble into 24 distinct integrins (Fig. 1). The different combination of subunits accounts for heterodimer specificity, with certain integrins showing preference for particular ECM... 

Integrins are adhesion molecules involved in cell-matrix interaction. Integrins are heterodimeric membrane glycoproteins formed by the combination of an a- and p-subunit with an intracellular and an extracellular domain [115]. In the brain, endothelial cells, astrocytes, and the basal membrane such as laminin and collagen contribute to form the... 

Fig. 18. Subunits and assembly of integrins. Seven 3 subunits and fourteen a subunits are shown which can form in various combinations to produce dimeric, non-covalently bonded complexes with various ligand binding properties, some of which are indicated in boxes. Abbreviations Fn, fibronectin Lm, laminin coll, collagen Fb, fibrinogen Op, osteopontin ICAM, ICAM family 1 or 2 BM, unidentified basement membrane component(s). a, is also called pl50 or GDI Ic Ol and are GDI la and GDI lb, respectively 32 is GDIS in the immunological literature.

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