DMP1 is an extracellular matrix protein and a member of the small integrin binding ligand N-linked glycoprotein family. It is critical for proper mineralization of bone and dentin, and is present in diverse cells of bone and tooth tissues. DMP1 contains a large number of acidic domains, multiple phosphorylation sites, a functional arg-gly-asp cell attachment sequence, and a DNA binding domain. DMP1 may also have a dual function during osteoblast differentiation. In the nucleus of undifferentiated osteoblasts the unphosphorylated form acts as a transcriptional component for activation of osteoblast-specific genes like osteocalcin. During the osteoblast to osteocyte transition phase it is phosphorylated and exported into the extracellular matrix, where it regulates nucleation of hydroxyapatite.

Nucleus. Cytoplasm. Secreted; extracellular space; extracellular matrix. Note=In proliferating preosteoblasts it is nuclear, during early maturation stage is cytoplasmic and in mature osteoblast localizes in the mineralizated matrix. Export from the nucleus of differentiating osteoblast is triggered by the release of calcium from intracellular stores followed by a massive influx of this pool of calcium into the nucleus.