title: Calcineurin regulates phosphorylation status of transcription factor osterix.
abstract: Osterix is an osteoblast-specific transcriptional factor that is essential for osteoblast differentiation and bone formation. Calcineurin regulates bone formation through modulating osteoblast differentiation. However, post-translational modification of osterix such as phosphorylation and interactions between osterix and calcineurin remains unclear. In the present study, we demonstrated that calcineurin interacted with osterix determined by immunoprecipitation assay and Western analysis. Immunocytochemical study also revealed that osterix and calcineurin were co-localized in nucleus. Deletion of calcineurin binding motif on osterix molecule disrupted osterix-calcineurin interaction. Phosphorylation status of osterix was augmented by treatment with phosphatase inhibitors, FK506 and calyculin A. In contrast, treatment of recombinant calcineurin reduced phosphorylation status of osterix. Our present study suggests that calcineurin has an important role in the function of osterix through its modification of phosphorylation.
authors.affiliation: Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15, Kuramoto, Tokushima 770-8504, Japan. okamura@dent.tokushima-u.ac.jp
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Okamura
authors.forename: Bruna Rabelo
authors.initials: BR
authors.lastname: Amorim
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.forename: Kaya
authors.initials: K
authors.lastname: Yoshida
authors.forename: Tatsuji
authors.initials: T
authors.lastname: Haneji
mesh_terms: D000818:Animals; D019703:Calcineurin / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D010766:Phosphorylation; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000076182:Sp7 Transcription Factor; C479466:Sp7 protein, mouse; D014157:Transcription Factors; D019703:Calcineurin