May act as a cross-bridge between fibrils and other extracellular matrix molecules. Involved in skeletal myogenesis in the developing esophagus. May play a role in organization of the pericellular matrix or the sphinteric smooth muscle. Oligomer; disulfide-linked. Localized to vascular, neuronal, mesenchymal, and some epithelial basement membrane zones in umbilical cord. The numerous interruptions in the triple helix may make this molecule either elastic or flexible. Prolines at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains. Belongs to the fibril-associated collagens with interrupted helices (FACIT) family.