Cell receptors, integrin sequences

On such modified surfaces, some of the attached proteins are recognized by cytoskeletally associated receptors in the cell membrane. So, in the end, the extracellular substrate is mechanically connected with the intracellular cytoskele-ton, which may secrete its own adhesion proteins. Integrins, as an important class of cell receptors [63], bind to small domains on their adhesion proteins, e.g., the oligopeptide sequence arginine-glycine-aspartic acid (RGD) that is common in fibronectin [64],... 

Cells have surface receptors (integrins) that bind to known peptide sequences, such as RGD. 

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. 

Figure 48-3. Schematic representation of fibronectin. Seven functional domains of fibronectin are represented two different types of domain for heparin, cell-binding, and fibrin are shown. The domains are composed of various combinations of three structural motifs (I, II, and III), not depicted in the figure. Also not shown is the fact that fibronectin is a dimer joined by disulfide bridges near the carboxyl terminals of the monomers. The approximate location of the RGD sequence of fibronectin, which interacts with a variety of fibronectin integrin receptors on cell surfaces, is indicated by the arrow. (Redrawn after Yamada KM Adhesive recognition sequences.

Figure 48-4. Schematic representation of a cell interacting through various integrin receptors with collagen, fibronectin, and laminin present in the ECM. (Specific subunits are not indicated.) (Redrawn after Yamada KM Adhesive recognition sequences. J Biol Chem 1991 266 12809.)...

Baiillari G, Gendelman R, Gallo RC, Ensoli B (1993) The Tat protein of human immunodeficiency virus type 1, a growth factor for AIDS Kaposi sarcoma and cytokine-activated vascular cells, induces adhesion of the same cell types by using integrin receptors recognizing the ROD amino acid sequence. Proc Natl Acad Sci USA 90(17) 7941-7945... 

Figure. 4. Principle of the cell adhesion to artificial materials. In cell culture media or body fluids, the material is spontaneously adsorbed with cell adhesion-mediating extracellular matrix proteins (e g., vitronectin, fibronectin). The cells then adhere to specific amino acid sequences of these proteins by their adhesion receptors of integrin or non-integrin type [38-41].

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