Galectins as modulators of cell adhesion

The galectins are a family of carbohydrate-binding proteins that are distri buted widely in metazoan organisms. Each galectin exhibits a specific patte rn of expression in various cells and tissues, and expression is often clos ely regulated du ng development. Although these proteins are found mainly i n the cell cytoplasm, some are secreted from cells and interact with approp riately glycosylated proteins at the cell surface or within the extracellul ar matrix. These receptors include cell-adhesion molecules such as integrin s, and matrix glycoproteins such as laminin and fibronectin isoforms. Recen t studies have increased understanding of the roles of the galectins in reg ulating cell-cell and cell-matrix adhesion. These interactions are critical ly involved in modulation of normal cellular motility and polarity and duri ng tissue formation, and loss of adhesive function is implicated in several disease states including tumour progression, inflammation and cystic devel opment in branching epithelia such as kidney tubules. This review discusses recent progress in defining the specificities and mechanisms of action of secreted galectins as multifunctional cell regulators. (C) 2001 Societe fra ncaise de biochimie et biologie moleculaire / Editions scientifiques et med icales Elsevier SAS. All rights reserved.