Cytoskeletal reorganization mediates fluid shear stress-induced ERK5 activation in osteoblastic cells

Cell Biol Int. 2012 Mar 1;36(3):229-36. doi: 10.1042/CBI20110113.


Mechanotransduction is a complicated process, of which mechanosensation is the first step. Previous studies have shown that the cytoskeleton plays a crucial role in mechanosensation and the mediation of intracellular signal transduction. However, the mechanism of mechanotransduction in the bone remains elusive. Here, we investigated the potential involvement of a novel MAPK (mitogen-activated protein kinase) member, ERK5 (extracellular-signal-regulated kinase 5), in the response of osteoblastic cells to FSS (fluid shear stress). Our results demonstrated that ERK5 was rapidly phosphorylated in pre-osteoblastic MC3T3-E1 cells upon FSS, and the integrity and reorganization of the cytoskeleton were critical in this process, in which the cytoskeleton-dependent activation of FAK (focal adhesion kinase) may be involved in the activation of ERK5 induced by FSS. Moreover, we found that cytoskeletal disruption led to significant down-regulation of ERK5 phosphorylation, but had no effect on ERK5 nuclear localization. Furthermore, the cytoskeleton rapidly reorganized in response to FSS, but long-time fluid load, even at a physiological level, led to cytoskeletal disruption, suggesting that other pathways may be involved in long-term mechanotransduction. Taken together, our data provide new insight into the mechanisms of mechanosensation by highlighting the link between ERK5 activation and cytoskeletal reorganization in osteoblasts undergoing FSS.

MeSH terms

  • Animals
  • Cells, Cultured
  • Cytoskeleton / metabolism*
  • Down-Regulation
  • Mechanotransduction, Cellular
  • Mice
  • Mitogen-Activated Protein Kinase 7 / genetics
  • Mitogen-Activated Protein Kinase 7 / metabolism*
  • Osteoblasts / metabolism*
  • Stress, Mechanical*


  • Mitogen-Activated Protein Kinase 7