Okadaic acid stimulates the expression of receptor activator of nuclear factor-kappa B ligand (RANKL) in mouse osteoblastic cells

Kaya Yoshida, Hirohiko Okamura, Hiroyuki Morimoto, Toshihiko Nagata, Tatsuji Haneji

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5 Citations (Scopus)


Receptor activator of nuclear factor-κB ligand (RANKL) is a membrane-bound signal transducer responsible for differentiation and maintenance of osteoclasts. To investigate a possible relationship between the status of protein phosphorylation and the regulation of RANKL in osteoblasts, we examined the effects of okadaic acid, a potent inhibitor of protein phosphatases, on cultured mouse osteoblastic MC3T3-E1 cells. Okadaic acid increased the amounts of RANKL protein in a dose-dependent fashion, with the maximum effective concentration being 100 nM. Okadaic acid at 100 nM stimulated the expression of RANKL mRNA and protein in MC3T3-E1 cells in a time-dependent manner up to 3 h. Okadaic acid also stimulated the expression of the Cbfa1 protein, a transcription factor required for osteoblast differentiation, in a dose-dependent manner. Binding of nuclear proteins prepared from MC3T3-E1 cells to Cbfa1 consensus sequence increased in a time-dependent manner when the cells had been treated with 100 nM okadaic acid. A 200-fold excess of unlabelled Cbfa1 oligonucleotide completely inhibited the DNA-protein complex formation. Our study demonstrate that okadaic acid stimulate RANKL production in MC3T3-E1 cells, indicating that the serine/threonine protein phosphatases play an important role in the regulation of bone metabolism.

Original languageEnglish
Pages (from-to)126-132
Number of pages7
JournalBiomedical Research
Issue number2
Publication statusPublished - Oct 1 2003



  • Cbfa1
  • Okadaic acid
  • Osteoblast
  • Protein phosphatase

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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