Journal of Bone and Mineral Metabolism

, Volume 29, Issue 3, pp 279–290

Characterization of the osteoblast-specific transmembrane protein IFITM5 and analysis of IFITM5-deficient mice

Authors

    • Nanotechnology Innovation CenterNational Institute for Materials Science
    • Graduate School of Life ScienceHokkaido University
  • Xianglan Li
    • Nanotechnology Innovation CenterNational Institute for Materials Science
  • Hiromi Morita
    • Nanotechnology Innovation CenterNational Institute for Materials Science
  • Taro Takemura
    • Nanotechnology Innovation CenterNational Institute for Materials Science
  • Jie Li
    • Nanotechnology Innovation CenterNational Institute for Materials Science
  • Takashi Minowa
    • Nanotechnology Innovation CenterNational Institute for Materials Science
Original Article

DOI: 10.1007/s00774-010-0221-0

Cite this article as:
Hanagata, N., Li, X., Morita, H. et al. J Bone Miner Metab (2011) 29: 279. doi:10.1007/s00774-010-0221-0

Abstract

Interferon-inducible transmembrane protein 5 (IFITM5) is an osteoblast-specific membrane protein whose expression peaks around the early mineralization stage during the osteoblast maturation process. To investigate IFITM5 function, we first sought to identify which proteins interact with IFITM5. Liquid chromatography mass spectrometry revealed that FK506-binding protein 11 (FKBP11) co-immunoprecipitated with IFITM5. FKBP11 is the only protein it was found to interact with in osteoblasts, while IFITM5 interacts with several proteins in fibroblasts. FKBPs are involved in protein folding and immunosuppressant binding, but we could not be sure that IFITM5 participated in these activities when bound to FKBP11. Thus, we generated Ifitm5-deficient mice and analyzed their skeletal phenotypes. The skeletons, especially the long bones, of homozygous mutants (Ifitm5−/−) were smaller than those of heterozygous mutants (Ifitm5+/−), although we did not observe any significant differences in bone morphometric parameters. The effect of Ifitm5 deficiency on bone formation was more significant in newborns than in young and adult mice, suggesting that Ifitm5 deficiency might have a greater effect on prenatal bone development. Overall, the effect of Ifitm5 deficiency on bone formation was less than we expected. We hypothesize that this may have resulted from a compensatory mechanism in Ifitm5-deficient mice.

Keywords

IFITM5OsteoblastsProtein interactionKnockout miceBone growth

Copyright information

© The Japanese Society for Bone and Mineral Research and Springer 2010