18 Questions
What is the function of proteoglycans in the ECM?
Act as tissue organizers
How are glycosaminoglycans attached to proteoglycans?
Covalently to a SGxG consensus motif within the protein
What are the two major families of membrane attached proteoglycans?
Syndecans and Glypicans
How do Syndecans attach to the membrane?
Via a single transmembrane domain
How are Glypicans anchored to the membrane?
Via a GPI anchor
What process allows cells to change their surface features quickly?
Proteoglycan shedding
What is the physiological role of Heparin?
The physiological role of Heparin is unclear.
What is the structure of Heparin that contributes to its extended rod-like helical conformation?
The negatively charged groups (SO4 and COO-) repel one another, leading to the extended rod-like helical conformation.
What is the function of the Glycocalyx in eukaryotic cells?
The Glycocalyx serves as an information-rich carbohydrate layer extending from the cell surface.
Differentiate between Glycoproteins, Proteoglycans, and Glycosphingolipids.
Glycoproteins are proteins modified by oligosaccharides, Proteoglycans have glycosaminoglycans attached to a 'core protein,' and Glycosphingolipids have oligosaccharides attached to sphingosine.
Describe the structure of Proteoglycans and how they are attached to proteins.
Proteoglycans have glycosaminoglycans attached to a 'core protein.'
What are Syndecans and Glypicans?
Syndecans and Glypicans are membrane-attached proteoglycans.
What is the role of aggrecan core protein in the extracellular matrix?
Contributing to tensile strength and resilience of connective tissue
How are proteoglycan aggregates bound to hyaluronate?
Via linker proteins
What is the function of fibronectin in the extracellular matrix?
Binding heparan sulfate, collagen, and integrins
How do integrins interact with the extracellular matrix?
By linking to the cytoskeleton of the cell
What percentage of mammalian proteins are glycosylated?
About half
How are O-linked saccharides connected to proteins?
By connecting the anomeric carbon to the -OH of Ser or Thr
Learn about the role of proteoglycans in the cell surface and extracellular matrix (ECM), and how they act as tissue organizers and influence cellular processes like attachment and growth factor activation. Understand the attachment of glycosaminoglycans to proteins and the significance of a tetrasaccharide linker.
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