In order to move, non-muscle cells are able to display stress fibers which consist of actin filaments, crosslinking proteins, and myosin II motors. These structures can also arise from tension applied on the cells, as these UCSD researchers showed here. They stretched cells in a workout chamber the size of a credit card to gain a better understanding of how repetitive stretching of endothelial cells that line arteries can make them healthy and resistant to vascular diseases. (jacobsschool.ucsd.edu)
An unstreched cell displays random patterns of stress fibers, which get more organized and align following the stretching force, the more the cell undergoes tension.