​Extracellular matrix comprises various proteins and polysaccharides that assemble into an organized meshwork. This associates with the cells that produce them. Given below are a few statements regarding different components of the matrix:

A. Collagen is the major protein of the extracellular matrix and is a long, triple-stranded helical structure.
B. Hyaluronan, which is produced in large quantities during wound healing, is a type of glycosaminoglycan (GAG) that contains sulfated sugar and is covalently linked to the core protein.
C. Syndecans are plasma membrane proteoglycans that interact with the actin cytoskeleton and signaling molecules of the cell cortex.
D. Decorin is a small proteoglycan secreted by fibroblasts and contains 1-10 GAG chains.

Which one of the following options represents INCORRECT statement/s?

Correct option is D

​Explanation:

• Statement A (Correct)
• Collagen is the most abundant structural protein in the extracellular matrix (ECM).
• It forms a triple-stranded helical structure that provides mechanical strength and elasticity.
• Statement B (Incorrect)
• Hyaluronan (Hyaluronic acid) is a glycosaminoglycan (GAG), but it is NOT sulfated and does NOT attach to a core protein like other GAGs.
• Unlike other GAGs, hyaluronan is synthesized directly at the plasma membrane, instead of being synthesized in the Golgi and secreted.
• Statement C (Correct)
• Syndecans are transmembrane proteoglycans (not just plasma membrane-associated).
• They interact with the actin cytoskeleton and various signaling molecules, helping in cell adhesion, migration, and growth factor binding.
• Statement D (Incorrect)
• Decorin is a small leucine-rich proteoglycan that plays a role in collagen fibril formation and regulation of cell growth.
• However, it typically contains only one GAG chain, not 1–10.

Since the only incorrect statement is B, the correct answer is option (d) B only.

Information Booster:

1. Collagen provides tensile strength to tissues like bones, tendons, and skin.
2. Hyaluronan is important for tissue hydration and lubrication, especially in joints.
3. Syndecans play a role in cell-matrix adhesion and signal transduction.
4. Decorin regulates collagen fibril spacing and influences cell proliferation.
5. Glycosaminoglycans (GAGs) like chondroitin sulfate and heparan sulfate attach to core proteins to form proteoglycans, except hyaluronan.
6. Proteoglycans contribute to hydration, resilience, and biochemical signaling in tissues.