PROTRUSIVE ACTIVITY QUANTITATIVELY DETERMINES THE RATE AND DIRECTION OF CELL LOCOMOTION

Locomoting blebbing cells have been used as a model to obtain novel in sight into the mechanisms of cell locomotion. We tested the hypothesis that locomotion can be due to progressive one-sided protrusion of cel lular volume into pseudopods. The hypothesis is supported by the findi ng that the rate and direction of locomotion of individual Walker carc inosarcoma cells can be predicted by sequential measurement of protrus ive activity. Protrusive activity at the front is closely associated w ith forward movement of the rear part of the cell. During bleb formati on the cell membrane of Walker carcinosarcoma cells is pushed forward faster (1.2-4.1 mu m/sec) than known rates of actin elongation. (C) 19 96 Wiley-Liss, Inc.