Effects of cyclic tensile strain on the cytoskeletal arrangement and activation of focal adhesion kinase in murine myoblastic precursors

Mechanical stimulation has been shown capable of modulating cell behaviour. By mechanotransduction cells are able to translate extrinsic stimuli into chemical signals that can affect migration, proliferation, transcription and apoptosis. Focal adhesion kinase is a focal adhesion-associated protein kinase which is involved in binding of the cell to extracellular compartments. Recently, focal adhesion kinase has been associated as key factor in translating extrinsic signals into cellular response. In this work, the effect of cyclic tensile strain on myoblasts ability to assemble focal adhesions and in turn recruit and activate focal adhesion kinase was analysed with immunofluorescence techniques. Subconfluent mouse myoblastic precursors were cultured on flexible-bottomed culture plates and subjected to uniaxial or equibiaxial cyclic strain before stained for vinculin, focal adhesion kinase and Tyr397 phosphorylated focal adhesion kinase. Cell subjected to cyclic strain obtained elongated morphology with clear formation of focal adhesions. Colocalised to the focal adhesions were recruited focal adhesion kinase which was then phosphorylated. The cyclic tensile strains were capable of inducing cytoskeletal reorientation in myoblast as well as recruit and activate focal adhesion kinase.