Cell adhesion codes

Tumor suppressor genes are genes that, by their inactivation due to mutations or deletion, promote tumor formation. The proteins for which they code are known as tumor suppressor proteins. Many of the known tumor suppressor proteins have a suppressing and negatively regulating effect on processes that are either directly associated with regulation of cell division or influence this in an indirect way. Other, equally important functions of tumor suppressor proteins are in the areas of DNA repair and cell adhesion. Inactivation of tumor suppressor genes can have various consequences ... 

Neurexin-1, a trans-synaptic cell adhesion molecule that binds to neuroligins, has also been implicated in ASD (Szatmari et al., 2007 Feng et al., 2006). Briefly, large internal deletions in neurexin-1 coding exons were found in two affected siblings... 

Boucard, AA, Chubykin, AA, Comoletti, D, Taylor, P and Sudhof, TC (2005) A splice-code for trans-synaptic cell adhesion mediated by binding of neuroligin 1 to a- and P-neurexins. Neuron 48(2) 229-236. 

RGD is the one-letter amino acid code abbreviation for arginine-glycine-aspartic acid. Peptide sequences containing a RGD motif are used as specific ligands to mediate cell adhesion. 

Proteins have many functions in the body. They serve as transporters of hydrophobic compounds in the blood, as cell adhesion molecules that attach cells to each other and to the extracellular matrix, as hormones that carry signals from one group of cells to another, as ion channels through lipid membranes, and as enzymes that increase the rate of biochemical reactions. The unique characteristics of a protein are dictated by its linear sequence of amino acids, termed its primary structure. The primary structure of a protein determines how it can fold and how it interacts with other molecules in the cell to perform its function. The primary structures of all of the diverse human proteins are synthesized from 20 amino acids arranged in a linear sequence determined by the genetic code. 

A more selective inhibition of NFkB can be achieved by transfecting cells with DNA coding for the natural inhibitor IkBo or a mutant IkB protein that lacks 36 N-terminal amino acids, and consequently becomes proteolysis resistant. In this way expression of adhesion molecules and monocyte adhesion and transmigration can be inhibited [87,88], The potentials and limitations of these latter types of therapy are however not fully understood as yet. Different transfection systems (adenoviral, retroviral, non-viral) are available for gene delivery purposes, all with their own potentials and restrictions. 

The domain structure in fibronectins is made up of a few types of peptide module that are repeated numerous times. Each of the more than 50 modules is coded for by one exon in the fibronectin gene. Alternative splicing (see p. 246) of the hnRNA transcript of the fibronectin gene leads to fibronectins with different compositions. The module that causes adhesion to cells contains the characteristic amino acid sequence -Arg-Gly-Asp-Ser-. It is these residues that enable fibronectin to bind to cell-surface receptors, known as integrins. 

One opinion is that these differentiation antigens act as a postal code. By an adhesion system, they direct the route that embryonic cells should follow in order to arrive at their destination, notably to assemble in large organs. But the traffic must be organized by postmen or traffic controllers . Therefore, other molecules are needed to recognize these antigens, a role which neighbouring lectins could carry out. 

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