In recent years, cell adhesion and cell adhesion molecules have been shown to be important for many normal biological processes, including embryonic cell migration, immune system functions and wound healing. It has also been shown that they contribute to the pathogenesis of a large number of common human disorders, such as rheumatoid arthritis and tumor cell metastasis in cancer. | Turk J Biol 25 (2001) 1-15 © T†BÜTAK Review Article Cellular Adhesion and Adhesion Molecules Zerrin SELLER University of Anatolia, Department of Pharmacology, TBAM, Eskißehir-TURKEY Received: Abstract: In recent years, cell adhesion and cell adhesion molecules have been shown to be important for many normal biological processes, including embryonic cell migration, immune system functions and wound healing. It has also been shown that they contribute to the pathogenesis of a large number of common human disorders, such as rheumatoid arthritis and tumor cell metastasis in cancer. In this review, the basic mechanisms of cellular adhesion and the structural and functional features of adhesion molecules are summarized. Introduction Cells in vivo must form contacts with their neighbours or with an extracellular matrix (ECM) in order to form tissues or organs. The macromolecular components of ECM, which are secreted by resident cells, include proteglycans, glycoproteins and collagens, which may function as tracks, directing migrating cells along a particular route. Other members of the ECM, including adhesive molecules such as laminin, vitronectin and fibronectin, facilitate the adherence of cells to their substratum as they migrate. ECM not only fills intercellular spaces, shaping and strengthening many tissues, but also influences celluar functions such as state of differentiation and proliferation (1, 2, 4). Evidence originally obtained from studies with antisera against cell surface proteins revealed that the morphology of cells bound to the ECM could be modified and that these cells could become de-attached by such treatments, suggesting that specific receptors regulated the process (2). In the last 20 years, the nature of many of these cell adhesion receptors has been elucidated, while the use of synthetic peptides or proteolytic fragments of adhesive proteins has revealed the nature of cell-binding sites on these receptors (3, 4). Cell adhesion .