Fibronectin and Laminin

Proteins with Biological Activity Fibrous Proteins 207 

In the extracellular matix, fibronectin serves as the matrix organizer. This is still poorly understood, but it is known that fibronectin can interact with proteoglycans, collagens, and cells enmeshed in the matrix, where it binds cells together and anchors them to the matrix. This function also follows fibronectin to act as a mediator of cell growth and differentiation. In some cell systems such as the epithelial cells, this function is replaced by another tissue glycoprotein, laminin. 

---

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.)...

The major components of the ECM are the structural proteins collagen, elastin, and fibrihin a number of specialized proteins (eg, fibronectin and laminin) and various proteoglycans. 

Early attempts to functionalize biomaterial surfaces with biological molecules were focused on improving blood compatibility of cardiovascular devices, such as the artificial heart and synthetic blood vessels, by immobilizing heparin or albumin on polyurethane or Dacron . To enhance cell adhesion to biomaterial surfaces, entire extracellular matrix (ECM) proteins, such as fibronectin and laminin, have been used directly as coatings. However, because of the nonspecific manner of whole protein adsorption, most of the cell binding capability is often lost. Using a molecular templating technique, it may be possible to select which protein(s) to absorb on biomaterial surfaces. ... 

Kamihagi K, Katayama M, Ouchi R, et al. Osteonectin/SPARC regulates cellular secretion rates of fibronectin and laminin extracellular matrix proteins. Biochem Biophys Res Commun. 1994 200 423-428. 

Various constituents of fibrosis can be detected with immunohistochemical stains collagen, fibronectin, and laminin.Type IV collagen works best for most brain and meningeal tissues. For routine identification of fibrosis, standard tinctorial stains rival immunohistochemical stains (see Fig. 20.4). 

Many of the extracellular materials are filaments made from fibrous proteins, mainly collagen and elastin, and adhesion proteins such as fibronectin and laminin. Collagens form a family of proteins with a tissue-specific distribution, including types inifound in connective tissue such as filamentsand types IV and Vfound in basal laminae forming sheets of tissue. 

Fibronectin and laminin are the principal adhesive glycoproteins in connective tissues and basal laminae (the structures underlying tissues that form sheets), respectively. Adhesive glycoproteins link the outer surfaces of cells... 

The extracellular matrix is connected to cells by adhesive glycoproteins, fibronectin, and laminin, which bind to integrins in the plasma membrane. 

Bronner-Fraser, M. (1986b) An antibody to a receptor for fibronectin and laminin perturbs cranial neural crest development in vivo. Dev. Biol. 117 528-536. 

Krotoski, D.M., Domingo, C. and Bronner-Fraser M. (1986) Distribution of a putative cell surface receptor for fibronectin and laminin in the avian embryo. J. Cell Biol. 103 1061-1071. 

Newgreen, D. (1984) Spreading of explants of embryonic chick mesenchymes and epithelia on fibronectin and laminin. Cell Tissue Res. 236 265-277. 

Perris, R., Pausson, M. and Bronner-Fraser, M. (1989) Molecular mechanisms of avian neural crest cell migration on fibronectin and laminin. Dev. Biol. 136 222-239. 

Inflammatory processes in the liver increase production of cytokines, chemokines, and signaling molecules, which activate the stellate cells to produce a complex extracellular glycoprotein matrix (i.e., the development of fibrosis). The matrix formed includes collagen, elastin, fibronectin, and laminin. Several noninvasive tests can be used as nonspecific indicators of fibrosis, but these have not been widely applied in laboratory animals. These tests include the collagen markers type III procollagen, YKL-40, and hyaluronic acid however, these tests have not been widely evaluated in laboratory animals (Cho and Lee 1998 Tran et al. 2000 Ding et al. 2001 Mardini and Record 2005). 

---