Vital Functions of Glycans in the Biological Systems

Glycans and their various conjugates namely glycoproteins, glycolipids, and proteoglycans not only coat all the cells in nature and interact with the extracellular matrix (ECM) molecules but are also located in the intracellular regions of every living organism. Glycans mediate or modulate numerous biological roles that are essential for life. This most abundant cellular molecule is necessary to maintain various general and specialized functions of the cells. Some of the major vital roles of glycans include maintenance of the structural integrity and protection of the cells, cell adhesion, cell-t- -cell communication, crosstalk, and bidirectional cell signaling (both inside out and outside in). Briefly, this chapter predominantly focuses on the role of glycans and their various conjugates in maintaining the structural integrity of biological membranes and the overall cells, the different modulatory functions of glycans, and their implication in nutrient sequestration. Additionally, a brief outline of the role of glycans on intrinsic or intra-species recognition and extrinsic or interspecies recognition is discussed. Overall, the biological importance of glycans and their conjugates is elaborated.