Extracellular processing of bone and dentin proteins in matrix mineralization.
There are two steps in the process of matrix-mediated bone and dentin mineralization. First, as in other soft tissues, osteoblasts/odontoblasts synthesize collagenous matrices and second, mineral deposits in these matrices at a location distant from the cells that synthesized the matrices. We suggest a sequence of events that lead the matrix to mineralization: the phosphoproteins of bone and dentin are posttranslationally processed by limited proteolysis, then they are extracellularly processed into a more phosphorylated species that, we believe, facilitates mineralization. Our in situ phosphorylation experiments done with [gamma-32P] GTP suggest the existence of extracellular phosphorylation by a casein kinase II (CKII)-like enzyme, the enzyme known to phosphorylate most of the phosphate residues in dentin phosphophoryn and bone sialoproteins (osteopontin and BSP II).
Suzuki
Y
Y
Department of Oral Biochemistry, Kanagawa Dental College, Yokosuka, Japan.
Kubota
T
T
Koizumi
T
T
Satoyoshi
M
M
Teranaka
T
T
Kawase
T
T
Ikeda
T
T
Yamaguchi
A
A
Saito
S
S
Mikuni-Takagaki
Y
Y
D000251:Adenosine Triphosphatases; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D002113:Calcification, Physiologic; D047390:Casein Kinase II; D002417:Cattle; D002454:Cell Differentiation; D003804:Dentin / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D008903:Minerals; D009804:Odontoblasts / Q000166:cytology; D010011:Osteocytes / Q000166:cytology; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases; D051381:Rats; D017207:Rats, Sprague-Dawley; D014074:Tooth Calcification
D016326:Extracellular Matrix Proteins; D008903:Minerals; D010750:Phosphoproteins; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D000251:Adenosine Triphosphatases