title: Akt phosphorylates and regulates the osteogenic activity of Osterix.
abstract: Osterix (Osx), a zinc-finger transcription factor is required for osteoblast differentiation and new bone formation during embryonic development. Akt is a member of the serine/threonine-specific protein kinase and plays important roles in osteoblast differentiation. The function of Osterix can be also modulated by post-translational modification. But, the precise molecular signaling mechanisms between Osterix and Akt are not known. In this study, we investigated the potential regulation of Osterix function by Akt in osteoblast differentiation. We found that Akt phosphorylates Osterix and that Akt activation increases protein stability, osteogenic activity and transcriptional activity of Osterix. We also found that BMP-2 increases the protein level of Osterix in an Akt activity-dependent manner. These results suggest that Akt activity enhances the osteogenic function of Osterix, at least in part, through protein stabilization and that BMP-2 regulates the osteogenic function of Osterix, at least in part, through Akt.
authors.affiliation: College of Pharmacy and Research Institute of Drug development, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: You Hee
authors.initials: YH
authors.lastname: Choi
authors.forename: Hyung Min
authors.initials: HM
authors.lastname: Jeong
authors.forename: Yun-Hye
authors.initials: YH
authors.lastname: Jin
authors.forename: Hongyan
authors.initials: H
authors.lastname: Li
authors.forename: Chang-Yeol
authors.initials: CY
authors.lastname: Yeo
authors.forename: Kwang-Youl
authors.initials: KY
authors.lastname: Lee
mesh_terms: D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D002454:Cell Differentiation; D057809:HEK293 Cells; D006801:Humans; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D010012:Osteogenesis; D010766:Phosphorylation; D055550:Protein Stability; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D000076182:Sp7 Transcription Factor; C478163:SP7 protein, human; D014157:Transcription Factors; D051057:Proto-Oncogene Proteins c-akt