Cell adhesion molecules (CAMs), also known as cell surface glycoproteins, contain three domains, namely a trans-membrane, extracellular and an intracellular domain . They adhere to proteoglycans and glycoproteins on the cell surface to mediate cell contacts and adhesion with the extracellular matrix (ECM). CAMs are sub-divided into four families, namely integrins, cadherins, selectins and immunoglobulin CAM (Ig-CAM), which function mainly in cell adhesion, migration, differentiation, proliferation and stimulating gene expression.
An Overview of Cell Adhesion Molecules (CAMs)
Cell adhesion molecules (CAMs) are molecules involved in the interaction between cells and extracellular matrix. CAM refers to the adhesion between cells, which is a form of information exchange between cells. CAM is a transmembrane glycoprotein. The molecular structure is composed of three parts: 1 extracellular region, N-terminal of peptide chain, with sugar chain. It is responsible for identifying the transmembrane region with ligands, most of which are transmembrane 3 cytosolic regions. The C-terminal part of the peptide chain is generally small, usually directly linked to the skeleton component under the plasma membrane or to the intracellular chemical signal molecules.
Major types of CAM
CAM can be classified into the following types according to their structural characteristics:
1. Immunoglobulin superfamily: some common adhesion molecules in immunoglobulin superfamily, such as CD4, CD8, CD22, CD28, CTLA-4, ICOS, ICAM-1, CD80, CD86, etc.
2. Integrin family: including β 1 group ~ β 88 group;
3. Selectin family: L- selectin P- selectin and E- selectin;
4. Mucin-like vascular address element;
5. Cadherin family.
Inhibition of CAM
Many methods of inhibiting adhesion molecules are directly acting on adhesion molecules or their ligands, which include a variety of substances, such as specific monoclonal antibodies to adhesion molecules, soluble forms of adhesion molecules, and small inhibitory molecules. In addition, cytokine specific antibodies, soluble cytokine receptors, and drugs that inhibit cytokines, such as corticosteroids and cyclosporine A, are strongly inhibited by cytokine activity.
CAM and diseases
CAM are closely associated with the development of stroke, diabetes and tumours. For example, the first domain of the extracellular domain of CD4 molecule is the site of gp120 recognition of envelope glycoprotein of human immunodeficiency virus. Human CD4 molecule is the main receptor of HIV. HIV infects CD4 T cells and selectively reduces the number and function of CD4-T cells. Monitoring the absolute number of CD4 positive cells in peripheral blood of HIV patients is of great value in the diagnosis and diagnosis of HIV infection and AIDS. The absolute number of CD4 T cells in peripheral blood of normal people was more than 500 / μ l. The decrease of CD4-T cells below 200 / μ l in HIV infected patients was a precursor to the deterioration of the disease.
Ji Kerou. Advances in Cell Adhesion molecules (Review) [J]. China urban and rural enterprises health 2007 (02): 37-42.