Family with sequence similarity 20, member C also known as FAM20C or DMP4 is a protein which in humans is encoded by the FAM20Cgene. Fam20C, a Golgi localized protein kinase, is a serine kinase that phosphorylates both casein and other highly acidic proteins and members of the small integrin-binding ligand, the N-linked glycoproteins (SIBLING) family at the target motif SerXGlu.
Dmp4 causes differentiation of mesenchymal stem cells into functional odontoblast cells and is likely to function as a regulator of dentin mineralization. FAM20C is a secretory kinase, responsible for the phosphorylation of all secreted proteins, from milk to bone proteins. Phosphorylation by Fam20C in the secretory pathway is essential for proper biomineralization of bone. The substrate specificity of FAM20C indicates, however, that it is not likely to account for the tyrosine phosphorylation of the secreted protein. The characterization of FAM20C as an active serine kinase in the Golgi apparatus provides a clear precedent that ATP dependent protein phosphorylation can take place in the secretory apparatus.
^ abHao J, Narayanan K, Muni T, Ramachandran A, George A (May 2007). "Dentin matrix protein 4, a novel secretory calcium-binding protein that modulates odontoblast differentiation". J. Biol. Chem.282 (21): 15357–65. doi:10.1074/jbc.M701547200. PMID17369251.
^Yalak G, Vogel V (December 2012). "Extracellular phosphorylation and phosphorylated proteins: not just curiosities but physiologically important". Sci Signal5 (255): re7. doi:10.1126/scisignal.2003273. PMID23250399.
Hao J, Narayanan K, Muni T, Ramachandran A, George A (2007). "Dentin matrix protein 4, a novel secretory calcium-binding protein that modulates odontoblast differentiation.". J. Biol. Chem.282 (21): 15357–65. doi:10.1074/jbc.M701547200. PMID17369251.
Simpson MA, Scheuerle A, Hurst J, Patton MA, Stewart H, Crosby AH (2009). "Mutations in FAM20C also identified in non-lethal osteosclerotic bone dysplasia.". Clin. Genet.75 (3): 271–6. doi:10.1111/j.1399-0004.2008.01118.x. PMID19250384.