Leading Edge Essay Glycomics Hits the Big Time Gerald W. Hart1,* and Ronald J. Copeland1 1Department of Biological Chemistry, School of Medicine, Johns Hopkins University, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA *Correspondence:
[email protected] DOI 10.1016/j.cell.2010.11.008 Cells run on carbohydrates. Glycans, sequences of carbohydrates conjugated to proteins and lipids, are arguably the most abundant and structurally diverse class of molecules in nature. Recent advances in glycomics reveal the scope and scale of their functional roles and their impact on human disease. By analogy to the genome, transcriptome, O-GlcNAc (Hart et al., 2007). Even though Dynamic Structural Complexity or proteome, the ‘‘glycome’’ is the the generic term ‘‘glycosylation’’ is often Underlies Glycan Functions complete set of glycans and glycoconju- used to categorize and lump all glycan Glycoconjugates provide dynamic struc- gates that are made by a cell or organism modifications of proteins into one bin, tural diversity to proteins and lipids that under specific conditions. Therefore, side by side with other posttranslational is responsive to cellular phenotype, to ‘‘glycomics’’ refers to studies that attempt modifications such as phosphorylation, metabolic state, and to the developmental to define or quantify the glycome of a cell, acetylation, ubiquitination, or methylation, stage of cells. Complex glycans play crit- tissue, or organism (Bertozzi and Sasise- such a view is not only inaccurate, but ical roles in intercellular and intracellular kharan, 2009). In eukaryotes, protein also is completely misleading. If one only processes, which are fundamentally glycosylation generally involves the cova- considers the linkage of the first glycan important to the development of multicel- lent attachment of glycans to serine, to the polypeptide in both prokaryotic lularity (Figure 1).