only in taxon only_in_taxon in taxon extracellular matrix collagen-containing extracellular matrix An extracellular matrix consisting mainly of proteins (especially collagen) and glycosaminoglycans (mostly as proteoglycans) that provides not only essential physical scaffolding for the cellular constituents but can also initiate crucial biochemical and biomechanical cues required for tissue morphogenesis, differentiation and homeostasis. The components are secreted by cells in the vicinity and form a sheet underlying or overlying cells such as endothelial and epithelial cells. cellular_component GO:0062023 2018-04-13T12:47:21Z dph Metazoa