dentin matrix acidic phosphoprotein 1; dentin matrix protein 1; DMP-1 (DMP1)

Function

• may have a dual function during osteoblast differentiation
• in the nucleus of undifferentiated osteoblasts, 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 & exported into the extracellular matrix, where it regulates nucleation of hydroxyapatite
• phosphorylated in the cytosol & extracellular matrix; unphosphorylated in the nucleus
• phosphorylation is necessary for nucleocytoplasmic transport & may be catalyzed by a nuclear isoform of CK2 & can be augmented by Ca+2
• interacts with importin alpha

Compartment

• nucleus, cytoplasm
• secreted, extracellular space, extracellular matrix
• in proliferating preosteoblasts, it is nuclear, during early maturation stage is cytoplasmic & in mature osteoblast localizes in the mineralizated matrix
• export from the nucleus of differentiating osteoblast is triggered by the release of Ca+2 from intracellular stores followed by a massive influx of this pool of Ca+2 into the nucleus

Alternative splicing

named isoforms=2

Expression

• expressed in tooth particularly in odontoblast, ameloblast & cementoblast

Pathology

• defects in DMP1 are the cause of hypophosphatemic rickets, autosomal recessive

More general terms

• matrix protein
• glycoprotein
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=1758
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:1758
• OMIM: https://mirror.omim.org/entry/241520
• OMIM: https://mirror.omim.org/entry/600980
• UniProt: http://www.uniprot.org/uniprot/Q13316.html