Anchorage proteins

Vinculin is one of a number of proteins that bind the actin network to the plasma membrane. It is a 130-kDa protein that is phosphorylated at a tyrosine residue by a kinase that is controlled by the src gene. Vinculin function is Ca2+-dependent, and it is found in close association with a-actinin. 

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Collagen Type Anchorage Protein Proteoglycan Cell Type... 

Figure 8.1. Generalized scheme of components involved in a cell s interaction with extracellular matrix within an intact tissue. Collagen-anchorage protein-proteoglygan combinations specific for various cell types are listed below. Ca2+ dependence is also indicated. Preparation of isolated cell suspension requires that these interactions be disrupted, as generally accomplished with proteolysis and Ca2+ chelation.

Synthetic Spider Silk Proteins for the In Vitro Proliferation of Anchorage-dependent Cells... 

At least seven proteins, besides the RNA-polymerase II, participate in the transcription machinery. The initiation of the transcription occurs when the transcriptional complex in the promoter region of the gene has been stabilized. The receptor dimer forms a complex of high affinity with the sequence of the HRE. This binding provides a firm base for the anchorage and stabilization of the transcriptional complex. The dimeric structure of the receptor acquires affinity to attract different coactivators that bring together the proteins of the transcriptional complex (Fig. 1.9). 

Additionally the membrane itself can contribute to further modifications of the protein-protein interactions. It can provide additional electrostatic and hydrophobic interactions distinct from the lipid anchorage and thereby affect conformation and/or activity of membrane associated proteins. 

Doubly-Lipid Modified Protein Sequence Motifs Exhibit Long-Lived Anchorage to Lipid Bilayer Membranes, S. Shahinian, J. R. Silvius, Biochemistry 1995, 34, 3813-3822. 

The integrins comprise a family of cell-surface proteins that are involved in adhesion, a process vital for many processes, such as anchorage, migration, growth and differentiation. Cells may adhere to other cells (cell-cell adhesion) or may interact with soluble molecules that constitute the extracellular matrix (cell-extracellular matrix). The integrins are linked to elements of the cytoskeleton, and so they provide a bridge between the external cellular environment and intracellular activation processes. 

A two-dimensional micropatterned tissue can be easily obtained by utihz-ing the inherent differences in cell adhesiveness between different micropatterned photografted regions. This was attained by photoiniferter graft polymerization with a projection mask placed on an iniferter-derivatized surface. Since protein adsorption and cell adhesion are markedly suppressed on nonionic graft polymers, such as polyDMAm, any anchorage-dependent cells such as endothelial cell adhere and proliferate only on nonirradiated surfaces, resulting in the formation of a two-dimensional patterned tissue or cellular sheet (Fig. 24). 

Plakins are not the only proteins that tether IFs to the cell surface. A number of other proteins localized to cell surface structures including desmosomes, focal contacts, and muscle costameres also contribute to IF anchorage at plasma membranes. IFs may also associate with cell surface receptors outside of ultrastructurally distinct structures, a topic that will be dealt with below. 

Bornslaeger, E. B., Corcoran, C. M., Stappenbeck, T. S., and Green, K. J. (1996). Breaking the connection Displacement of the desmosomal plaque protein desmo-plakin from cell-cell interfaces disrupts anchorage of intermediate filament bundles and alters intercellular junction assembly./. Biol. Chem. 134, 985-1002. 

Hopkinson, S. B., and Jones, J. C. (2000). The N terminus of the transmembrane protein BP180 interacts with the N-terminal domain of BP230, thereby mediating keratin cytoskeleton anchorage to the cell surface at the site of the hemidesmo-some. Mol. Biol. Cell 11, 277-286. 

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