The authors declared they have no conflict of interest.
Original Research Article
Protein phosphatase 2A Cα regulates osteoblast differentiation and the expressions of bone sialoprotein and osteocalcin via osterix transcription factor†
Article first published online: 28 JAN 2013
Copyright © 2012 Wiley Periodicals, Inc.
Journal of Cellular Physiology
Volume 228, Issue 5, pages 1031–1037, May 2013
How to Cite
Okamura, H., Yoshida, K., Yang, D. and Haneji, T. (2013), Protein phosphatase 2A Cα regulates osteoblast differentiation and the expressions of bone sialoprotein and osteocalcin via osterix transcription factor. J. Cell. Physiol., 228: 1031–1037. doi: 10.1002/jcp.24250
- Issue published online: 28 JAN 2013
- Article first published online: 28 JAN 2013
- Accepted manuscript online: 5 OCT 2012 07:48AM EST
- Manuscript Accepted: 26 SEP 2012
- Manuscript Received: 3 APR 2012
- Scientific Research Ministry of Education, Science, Sports, and Culture, Japan. Grant Number: 23592703
- Ichiro Kanehara Foundation, Promotion of Medical Sciences and Medical Care. Grant Number: 10KI171
Serine/threonine protein phosphatase 2A (PP2A) participates in regulating many important physiological processes such as cell cycle, growth, apoptosis, and signal transduction. Osterix is a zinc-finger-containing transcription factor that is essential for osteoblast differentiation and regulation of many bone-related genes. We have recently reported that decrease in α-isoform of PP2A catalytic subunit (PP2A Cα) accelerates osteoblast differentiation through the expression of bone-related genes. In this study, we further examined the role of PP2A Cα in osteoblast differentiation by establishing the stable cell lines that overexpress PP2A Cα. Overexpression of PP2A Cα reduced alkaline phosphatase (ALP) activity. Osteoblast differentiation and mineralization were also decreased in PP2A Cα-overexpressing cells, with reduction of bone-related genes including osterix, bone sialoprotein (Bsp), and osteocalcin (OCN). Luciferase assay showed that the transcriptional activity of the Osterix promoter region was decreased in PP2A Cα-overexpressing cells. Introduction of ectopic Osterix rescued the expression of Bsp and OCN in PP2A Cα-overexpressing cells. These results indicate that PP2A Cα and its activity play a negative role in osteoblast differentiation and Osterix is a key factor responsible for regulating the expressions of Bsp and OCN during PP2A Cα-mediated osteoblast differentiation. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.