Stretching mesangial cells stimulates tyrosine phosphorylation of focal adhesion kinase pp125FAK.

Mechanical loading of cultured mesangial cells has been shown to induce both increased production of matrix proteins and cell proliferation. This in vitro phenomenon has been implicated in the progression of glomerular sclerosis observed in a variety of glomerular diseases. However, it is not yet known how cells sense mechanical stress and transfer this sense into biochemical and biological events. In this study, we show that mesangial stretching rapidly stimulates tyrosine phosphorylation of non-receptor tyrosine kinase pp125FAK. Since pp125FAK is a major constituent of focal adhesions, our findings suggest that the focal adhesion may be a site where mechanical forces are translated into biochemical events, and that pp125FAK may play an important role in this signaling cascade.