called focal adhesions. Focal adhesions are physically linked to

tension-generating actin stress fibers inside the cell, allowing transfer of

intracellular force to the substrate. How stress fibers are assembled by

cells is not well-understood. We have developed and experimentally evaluated

a mathematical model for the reaction/diffusion/convection processes

involved in actin turnover in stress fibers. Model predictions are compared

to measured F-actin turnover inside living cells using live cell imaging and

FRAP. Our results suggest that new actin adds at sarcomeric dense bodies

along the length of stress fibers in diffusion-rate limited manner, as well

as at the stress fibers end located at focal adhesions. Preliminary

experiments to uncover the relationship between these processes and tension

generated by myosin will also be presented.