Plays a role during the calcification of cartilage and the transition of cartilage to bone. Found on some small banded collagen fibrils and filamentous meshworks. Highly expressed in cartilage, eye and ear. Expressed in 14.5 dpc in several cartilaginous structures including anlagen of several bones and the developing lungs as well as in the eye, ear and colon. First detectable at 12.5 dpc. At 14.5 dpc localizes to cartilage, developing dermis, cornea, the inner limiting membrane of the retina, and major arteries of the heart. At 18.5 dpc appears restricted mainly to cartilage where expression continued into adulthood. The C-terminal propeptide, also known as COLFI domain, have crucial roles in tissue growth and repair by controlling both the intracellular assembly of procollagen molecules and the extracellular assembly of collagen fibrils. It binds a calcium ion which is essential for its function (By similarity). Belongs to the fibrillar collagen family.