Surface molecules involved in cell-cell interactions (cell adhesion molecules) are integral membrane proteins with extracellular, transmembrane and cytoplasmic domains. They mediate cell adhesion by forming non-covalent bonds with corresponding surface molecules of neighbouring cells. Adhesion molecules can be classified as being involved in:
* Cell body to cell body adhesion:
Calcium-dependent adhesion molecules: cadherins (classic cadherins; des-mosomal cadherins). Cadherins are involved in homophilic cell-to-cell adhesion in the presence of calcium ions. They are cell surface adhesion molecules that interact with the intracellular actin cytoskeleton via plakoglo-bulin and catenin molecules. Neural (N)-cadherins, placental (P)-cadherins, and epithelial (E)-cadherins are recognised. Calcium-independent adhesion molecules, which belong to the immunoglobulin superfamily including intercellular adhesion molecules (ICAMs) and neural cell adhesion molecules(N-CAMs). Cell to cell surface carbohydrate ligand-binding proteins: selectins, which are divalent cation-dependent glycoproteins.
* Cell to extracellular matrix adhesion: the integrins. Integrins are a family of transmembrane proteins that act as receptors for extracellular matrix molecules, integrating the matrix and the cytoskeleton functionally and structurally. They are non-covalently attached heterodimeric glycoproteins, composed of alpha and beta subunits.
The role of cell adhesion molecules i Cell-cell recognition
0 Cell signalling
Cell migration Embryogenesis
Information transfer from the extracellular matrix to the cell Establishment of the blood-brain barrier Cancer metastasis
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