EGF-stimulated lamellipod extension in adenocarcinoma cells

The extension of lamellipodia has been triggered by the application of epid ermal growth factor (EGF). We have used an atomic force microscope (AFM) to investigate this lamellipodial extension. During extension we could detect an increase in height from about 500 nm for the stable lamellipodium to ty pical values of 600-800 nm for the extending lamellipodium. The AFM was als o used to determine the mechanical properties of the lamellipodium where we found a decrease of the elastic modulus by a factor of 1.4 at the same loc ation within the same cell. Both findings are consistent with the cortical expansion hypothesis, suggesting that severing of actin filaments, leading to a swelling of the cytoskeleton, generates the protrusive force during la mellipodial extension. (C) 2001 Elsevier Science B.V. All rights reserved.