ABSTRACT
Virtually all cells produce proteoglycans, which are macromolecules consisting of a protein core and one or more polysaccharide side chains. The polysaccharides are made up of unbranched chains of disaccharide repeats termed “glycosaminoglycans” (GAGs). Proteoglycans are either excreted into the extracellular matrix, installed into the cell membrane facing outward, or stored in vesicles inside the cell. The GAG portions of proteoglycans are able to interact with a myriad of proteins and thus are involved in a great number of physiological processes, including cell/matrix interactions (Monslow et al. 2015), angiogenesis (van Wijk and van Kuppevelt 2014), axon guidance (Rowlands et al. 2015), embryogenesis (Xiong et al. 2014), bone formation (Jochmann et al. 2014), coagulation, and many more. GAGs have been implicated in a number of pathologies, including cancer (Basappa et al. 2014), infl ammation (Pomin 2015), rheumatoid arthritis (Zhou et al. 2010), Alzheimer’s disease (Ariga et al. 2010), Parkinson’s disease (Lehri-Boufala et al. 2015), and infection (Kamhi et al. 2013). There are also several hereditary illnesses that are caused by defects in GAG degradation. These are collectively called mucopolysaccharidoses (MPS) (Cimaz and La Torre 2014), and it is estimated that one out of every 25,000 children born in the U.S. have an MPS.
