University:
University of Cincinnati Blue Ash
Course:
BIOL 5180 | Immunology
Academic year:

2024
Views:

155

Pages:

2
Author:

Jasper J.

(2). Adhesion molecules (i) Selectins Selectins areconnecting a group ofblood glycoprotein cell endothelium. adhesion molecules and playofan important role in cells to the The members this familymolecules of surfacehave molecules have three separate structural forms. These adhesion a single N-terminal (extracellular) lectin motif that precedes the epidermal growth factor. This compound is involved in lymphocyte This cells. carbohydrate-binding protein facilitatesnamely: adhesion of leukocytesmigration. to endothelial There are three types of selectins, * L-selectin (CD62L), expressed on leukocytes * P-selectin (CD62P), expressed on platelets and activated endothelium *specific E-selectin (CD62E),form expressed on activated endothelium isdomain, characterized by a structural consisting of an N-terminal lectin a domain with homology to epidermal factor (EGF) and various complements that regulate the repeat sequencegrowth of the protein. (ii) Integrins Integrins are ba chain familysubunits. of heterodimeric cell membrane glycoproteins consisting of a and Integrins function as extracellular matrix glycoprotein receptors.The main function of integrins is to link the cytoskeleton with extracellular ligands.cells, Integrins also participate in wound healing,deficiency cell migration, killing target and phagocytosis. Leukocyte adhesion syndrome occurs when the b subunits of LFA-1 and-2,Mac-1 arelaminin missing.(VLA-1, VLA -2, proteins facilitate cell binding of collagen (VLA-1, and -3), and -6), and fibronectin (VLA-3, -4, and -5). The intercellular contacts formed bymyeloid integrins are essentialcytotoxicity for immuneand responses, such as antigen presentation, cell-mediated phagocytosis. Integrins comprise an the important part ofacross the adhesion receptor cascade that guides leukocytes from bloodstream the endothelium and into injured tissue in response to chemotactic signals. (iii) Immunoglobulin superfamily The immunoglobulin superfamily is a group ofsimilar cell surface proteins characterized by the presence of 70-110 amino acids to the variable or constant parts of Ig or antibodies. Included in immunoglobulins are CD2, CD3, CD4, CD7, CD8, CD28,function-associated T cell receptor (TCR), MHC 3class I andIgG MHC class II and molecules, leukocyte antigen (LFA-3), receptors, several proteins. other.likeThese molecules are similar to each other, especially in the immunoglobulin domain. (iv) Cadherins Cadherins areenvironment. part of a family of adhesion molecules that allow cells to interact with their Cadherins help cells to communicate with other cells in immune surveillance, extravasation, tumor migration & metastasis, wound healing, and tissue localization. Cadherins are calcium-dependent. There are 5 T-cadherin, different types of cadherin N-cadherin,domain of Pcadherin, V-cadherin, andmolecules, E-cadherin.namely The cytoplasmic cadherins can interact withbased cytoskeleton proteins. These cadherin molecules may bind other receptors on homophilic specificity, but they still depend on intracellular interactions related to the cytoskeleton. (v) Mucins Mucins are glycated serine and threonine-rich proteins that function as ligands for selectins. Mucin contributes to the activation of the function of other adhesion molecules.