Basement membranes interactions

Zieske JD, Mason VS, Wasson ME, Meunier SF, Nolte CJ, Fukai N, Olsen BR, Par-enteau NL. Basement membrane assembly and differentiation of cultured corneal cells Importance of culture environment and endothelial cell interaction. Exp Cell Res 214 621-633 (1994). 

Valkonen, K. H., Wadstrom, T., and Moran, A. P. (1994). Interaction of lipopolysaccharides of Helicobacter pylori with basement membrane protein laminin. Infect. Immun. 62,3640-3648. 

Helix bundles. A third peptide chain can be added to a coiled coil to form a triple-stranded bundle.180-183 An example is the glycoprotein laminin found in basement membranes. It consists of three peptide chains which, for -600 residues at their C-terminal ends, form a three-stranded coil with heptad repeats.182184 Numerous proteins are folded into four helical segments that associate as four-helix bundles (Fig. 2-22).185-188 These include electron carriers, hormones, and structural proteins. The four-helix bundle not only is a simple packing arrangement, but also allows interactions between the + and - ends of the macro-dipoles of the helices. 

The net surface charge of a cell and the associated electrical double layer are important in interactions between cells and may influence the development of extracellular structure such as basement membranes. The net negative charge on cells also gives rise to an experimentally measurable electrophoretic mobility. 

Kawashima, H., Watanabe, N., Hirose, M., Sun, X., Atarashi, K., Kimura, T., Shikata, K., Matsuda, M., Ogawa, D., Heljasvaara, R., Rehn, M., Pihlajaniemi, T., and Miyasaka, M. (2003). Collagen XVIII, a basement membrane heparan sulfate proteoglycan, interacts with L-selectin and monocyte chemoattractant protein-1. / Biol. Chem. 278, 13069-13076. 

The structure of PTPo is consistent with its role in binding ligands on the surface of other cells or in the extracellular matrix. It interacts with heparin sulphate proteoglycan in the basement membrane (Sajnani-Perez et al. 2003). It may also bind to the C-terminal domain of cell surface-exposed nucleolin, a normally nuclear protein that is presented on the surface of developing muscle cells (Alete et al. 2006). However, these complexes seem to mediate structural or long-term regulatory interactions rather than short-term signaling to the neuronal secretory machinery. 

Recent studies have shown that all basement membranes contain a unique collagen arranged in an unusual network structure as well as certain glycoproteins and proteoglycans that occur only in basement membranes (Laurie et al., 1983). The cooccurrence of these proteins in basement membranes is due both to their synthesis by the cells that lie along the basement membrane and to strong and specific interactions that maintain the components together in situ. Also, the cells on basement membranes have specific receptors for these components (Yamada, 1983 von der Mark and Kiihl, 1985 Kleinman et al., 1985 Martin and Timpl, 1987). 

Collagen IV has been found to bind to both laminin and heparan sulfate proteoglycan, whereas laminin binds both the nidogen and heparan sulfate proteoglycan. These observations suggest that multiple interactions of a specific nature could be important in determining both the composition and the deposition of basement membranes. 

In summary, both collagen IV and laminin show the ability to self-assemble. In addition, the various components of basement membrane have an affinity for one another that involves binding to specific sites. These interactions generate rather defined aggregates in solution and lead to the deposition of the components in a gel-like form whose ultrastructure resembles in some details authentic basement membranes. Such multiple interactions would be expected to be stronger than single interactions and may account for the codistributions of these components in basement membranes. 

Kramer, R. H., Enenstein, J., and Waleh, N. S., Integrin structure and ligand specificity in cell-matrix interactions, in Molecular and Cellular Aspects of Basement Membranes (D. H. Rohrbach and R. Timpl, Eds.), pp. 239-258. Academic Press, New York, 1993. 

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