Collagen III

Collagen III (COL3A1) is a fibrillar extracellular matrix collagen synthesized as pre-procollagen and enriched in extensible tissues, including skin, blood vessels, intestine, uterus, and lung^[1]. Mechanistically, collagen III regulates collagen I fibrillogenesis, fibril diameter, extracellular matrix architecture, and tissue mechanical integrity^[2][3]. In wound models, collagen III supports re-epithelialization and limits scar-associated collagen fiber alignment, while reduced collagen III increases myofibroblast differentiation and scar deposition^[4][5]. In disease models, COL3A1 mutations or deficiency produce vascular and dermal fragility resembling vascular Ehlers-Danlos syndrome^[6][7]. Compared with collagen I, collagen III functions less as a dominant tensile scaffold and more as a fibril-network modifier that controls matrix organization, mechanosensing, and repair quality^[2][3][4]. For experimental applications, the collagen III N-propeptide cysteine-rich domain attenuates TGFβ signaling and suppresses fibroblast activation, supporting its use as a mechanistic inhibitor tool in fibrosis and scarring studies^[8].