Glycosaminoglycan biosynthesis and cartilage matrix enzymes

Glycosaminoglycan biosynthesis and cartilage matrix enzymes represent a complex network of proteins responsible for the formation and maintenance of the cartilage extracellular matrix (ECM) [PubMed: 28851905]. The biosynthetic component includes glycosyltransferases, such as xylosyltransferases (XYLT1/2) and galactosyltransferases, and various sulfotransferases that assemble and modify glycosaminoglycan (GAG) chains on proteoglycan cores like aggrecan [UniProt: Q86Y38]. Cartilage matrix enzymes also include degradative proteases, most notably matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family members, which mediate the physiological turnover and pathological breakdown of the matrix [PubMed: 21475201]. In diseases like osteoarthritis, an imbalance between these anabolic and catabolic activities leads to progressive cartilage loss and joint dysfunction [NIH: StatPearls]. Genetic mutations in biosynthetic enzymes can result in severe skeletal dysplasias or connective tissue disorders like Ehlers-Danlos syndrome [PubMed: 23440201]. While these enzymes are attractive therapeutic targets, developing selective inhibitors has proven difficult, often leading to side effects related to the systemic importance of ECM remodeling [PubMed: 17032161].

Other names

GAG biosynthetic enzymesCartilage extracellular matrix enzymesProteoglycan metabolic enzymes

Modulation of extracellular matrix turnover through the inhibition of catabolic enzymes (e.g., MMPs, ADAMTS) or the provision of substrates for anabolic biosynthetic pathways [PubMed: 21475201].