Osteopontin involvement in integrin-mediated cell signaling and regulation of expression of alkaline phosphatase during early differentiation of UMR cells.
To clarify the function of osteopontin in osteoblast differentiation, we have examined the signal transduction pathway in an osteoblastic cell line (UMR106-6) bound to osteopontin, fibronectin, vitronectin and collagen type I surfaces. This was done by investigating the production and autophosphorylation of focal adhesion kinase (FAK) and the expression of alkaline phosphatase (ALP) at the transcription level. Results suggest that osteopontin was not only responsible for the autophosphorylation of FAK but regulated the expression of ALP, which was strongly correlated with FAK activity. These results suggest that osteopontin might act as a trigger in the early differentiation of osteoblasts.
Liu
Y K
YK
Bionic Design Group, National Institute for Advanced Interdisciplinary Research, Tsukuba Research Center, Ibaraki, Japan.
Uemura
T
T
Nemoto
A
A
Yabe
T
T
Fujii
N
N
Ushida
T
T
Tateishi
T
T
D000469:Alkaline Phosphatase / Q000235:genetics*; D000818:Animals; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000378:metabolism; D002454:Cell Differentiation; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D016023:Integrins / Q000502:physiology*; D007700:Kinetics; D010006:Osteoblasts / Q000166:cytology* / Q000201:enzymology; D053495:Osteopontin; D012516:Osteosarcoma; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D012795:Sialoglycoproteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014407:Tumor Cells, Cultured
D015815:Cell Adhesion Molecules; D016326:Extracellular Matrix Proteins; D016023:Integrins; D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496052:Ptk2 protein, rat; D000469:Alkaline Phosphatase