expresses expresses superficial zone articular chondrocyte 2026-02-18T11:06:13Z An articular chondrocyte located in the most superficial zone of articular cartilage, characterized by flattened morphology and tangential alignment parallel to the joint surface, and residing within a matrix of fine collagen fibrils and relatively low proteoglycan content. In mice and humans, this cell typically expresses lubricin (PRG4) and contributes to lubrication and resistance to shear and tensile forces at the cartilage surface. articular chondrocyte proteoglycan 4