Distribution, gene expression, and functional role of EphA4 during ossification

Chisa Kuroda, Satoshi Kubota, Kazumi Kawata, Eriko Aoyama, Kumi Sumiyoshi, Morihiko Oka, Miho Inoue, Shogo Minagi, Masaharu Takigawa

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


EphA4 receptor tyrosine kinase has been shown to be critically involved in neural tissue development. Here, we found EphA4 was also distributed among hypertrophic chondrocytes and osteoblasts in the growth plate of developing mouse long bones. In vitro evaluation revealed that ephA4 expression was elevated upon hypertrophic differentiation of chondrocytes and that markedly stronger expression was observed in osteoblastic SaOS-2 than chondrocytic HCS-2/8 cells. Of note, RNAi-mediated silencing of ephA4 in SaOS-2 cells resulted in the repression of osteocalcin gene expression and alkaline phosphatase activity. Interestingly, confocal laser-scanning microscopic analysis revealed the presence of EphA4 molecules in the nucleus as well as on the surface of SaOS-2 cells. These findings are the first indication of a critical role of EphA4 in ossification, especially at the final stage in which osteoblasts and hypertrophic chondrocytes play major roles.

Original languageEnglish
Pages (from-to)22-27
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - Sept 12 2008


  • Calcification
  • Chondrocyte
  • Eph family
  • EphA4
  • Osteoblast

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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