Fluid flow-induced tyrosine phosphorylation and participation of growth factor signaling pathway in osteoblast-like cells |
| |
Authors: | Ogata T |
| |
Institution: | Department of Molecular Pharmacology, Division of Functional Disorder Research, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 101-0062, Japan. ogatatsk@wa2.so-net.ne.jp |
| |
Abstract: | To investigate how mechanical loading stimulates bone cells, we subjected murine osteoblast-like cells, MC3T3E1, to fluid flow generated by shaking culture dishes. Since we had previously found that egr-1 mRNA is up-regulated by the flow, and that the regulation involves tyrosine kinase, we examined which proteins are tyrosine-phosphorylated by flow. Western blotting and immunoprecipitation of cell lysates showed tyrosine phosphorylation enhancement of many proteins, including ERK2 and Shc, and activation of ERK1/2. Although these responses did not occur in serum-free media, addition of EGF or bFGF recovered the responses. AG1478, an inhibitor of EGF receptor kinase activity, abolished tyrosine phosphorylation enhancement, ERK1/2 activation, and egr-1 mRNA accumulation induced by the flow of EGF-containing serum-free media. These results suggest that growth factor signaling pathways are involved in these responses. Repetition of fluid flow induced repeatedly up-regulation of egr-1 mRNA. Such events may also occur in bone under mechanical loading. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|