|
|
||||||||
RECEPTORS AND SIGNAL TRANSDUCTION
Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 101-0062, Japan
Submitted 4 November 2002 ; accepted in final form 16 April 2003
To investigate how bone cells respond to mechanical stimuli, we subjected osteoblastic cells to fluid flow. We and others already reported that in a culture system of osteoblast-like cells, ERK1/2, Shc, and other proteins were tyrosine-phosphorylated by medium flow and the early response gene, egr-1 or c-fos mRNA, increased. These are the same as events found after stimulation by various growth factors. Moreover, because there were also reports suggesting that growth factor signaling is involved in the responses to mechanical stimuli, we examined the change in epidermal growth factor (EGF) receptor in the cells exposed to medium flow. The results demonstrated that EGF receptor protein increased after exposure to medium flow. This increase did not occur without serum in media, and the addition of EGF restored it. Furthermore, leupeptin blocked this increase. These results suggest that degradation of EGF-occupied EGF receptor by leupeptin-sensitive protease(s) in endosomes decreased with exposure to medium flow. This was presumed to participate, at least in part, in signaling of fluid flow.
mechanical stimuli; epidermal growth factor receptor; leupeptin; proteolysis
This article has been cited by other articles:
![]() |
M. Hughes-Fulford Signal Transduction and Mechanical Stress Sci. Signal., September 7, 2004; 2004(249): re12 - re12. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |