Osteomodulin (OMD) is a member of the small leucine-rich repeat proteoglycan family, which is involved in the organization of the extracellular matrix. OMD is located in bone tissue and is reportedly important for bone mineralization. Mechanistically, OMD could bind to BMP2 via its terminal leucine-rich repeats and formed complexes with BMP2 and its membrane receptors, thus promoting BMP/SMAD signal transduction. In addition, OMD was a putative target gene of SMAD4, which plays a pivotal role in this pathway.