Incorporated into fibronectin-containing matrix fibers. May play a role in cell adhesion and migration along protein fibers within the extracellular matrix (ECM). Could be important for certain developmental processes and contribute to the supramolecular organization of ECM architecture, in particular to those of basement membranes. Homomultimerizes and interacts with various extracellular matrix components such as FN1, LAMA1, NID, AGC1 and CSPG2. Isoform C is detected in the later blastula period, 4 hours after fertilization. Isoform D is not detected at this stage, it first appears during the gastrula period in 8 hours old embryos. Expression of both isoforms is then maintained throughout development. During later developmental stages, prominent expression is seen in regions where tissue compartments are continuously moving in relation to each other. Belongs to the fibulin family.