Cell adhesion integrins

The largest numbers of integrins are members of the (31 integrins, also known as the very late antigen (VLA) subfamily because of its late appearance after activation. There are at least seven receptors characterized from this subfamily, each with different ligand specificity. Among the most studied include the 04(31 and a5 31 receptors. The leukocyte integrin a4 31 is a cell adhesion receptor that is predominantly expressed on lymphocytes, monocytes and eosinophils. 

Integrins, selectins, cadherins, claudins and other cell adhesion molecules are involved in the interaction of cells with other cells or with extracellular matrix components. Some of them also serve as receptors by inducing outside-in or additional inside-out signaling. 

The leukocyte integrin a 4(3 1 (also known as VLA-4 and CD49d/CD29) is a cell adhesion receptor, which is predominantly expressed on lymphocytes, monocytes and eosinophils. VLA-4 is generally selective for the CS1 domain within fibronectin, with an essential requirement for LDV sequence for binding. VLA-4 also binds to VCAM-1 as a counter receptor. 

Integrins constitute a large family of a (3 heterodimeric cell surface, transmembrane proteins that interact with a large number of extracellular matrix components through a metal ion-dependent interaction. The term integrin reflects their function in integrating cell adhesion and migration with the cystoskeleton. 

Ruoslahti E, Pierschbacher MD (1987) New perspectives in cell-adhesion - RGD and integrins. Science 238 491M97... 

A 3D model of the fibrinogen-derived (very late antigen-4, VLA-4) inhibitor 4-[N -(2-methylphenyl)ureido]phenylacetyl-Leu-Asp-Val was derived from the X-ray structure of the related integrin-binding region of the vascular cell adhesion molecule-1 (VCAM-1). A 3D pharmacophore was generated with the program Catalyst, and a 3D search was performed in 8624 molecules from... 

LFA-1 Leucocyte function-associated antigcn-1 also known to be member of the (3-2 integrin family of cell adhesion molecules... 

Keselowsky BG, Collard DM, Garcia AJ (2003) Surface chemistry modulates fibronectin conformation and directs integrin binding and specificity to control cell adhesion. J Biomed Mater Res 66A 247-259... 

CD9 is a well-characterized hematopoietic tetraspan protein that has been shown to be present in CNS and PNS myelin, although it is present at higher levels in PNS myelin. In other cells, it is involved in integrin signaling and cell adhesion and motility. It is expressed at late stages of myelination and in the CNS is primarily found in paranodal junctions [34]. While compact CNS myelin is apparently normal in CD9-null animals, the paranodal loops are often disconnected from axonal membranes, and the transverse bands of the paranodal loops are lost. In the PNS, in addition to altered paranodes, hypermy-elination occurs. Thus, this tetraspan protein appears to act primarily at paranodes, where it is crucial for normal paranodal junctions. 

Milner, R. and Campbell, I. L. The integrin family of cell adhesion molecules has multiple functions within the CNS. J. Neurosci. Res. 69 286-291,2002. 

Adhesion molecules such as LI, neural cell adhesion molecule (N-CAM) and N-cadherin promote axonal regeneration by homophilic interactions between axons and Schwann cell surfaces (see Ch. 7). The expression of p75 (low affinity NGF receptor, Ch. 27) is also increased at the Schwann cell surface after injury. Extracellular matrix molecules, such as tenascin and proteoglycans, increase the regenerative potential of damaged peripheral nerves by binding to integrins on the axonal surface. 

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