[Biomechanics of actomyosin-dependent mobility of keratinocytes]

Migration of epidermal skin cells, keratinocytes, plays an important role in processes as wound healing or melanoma formation. Thus, characterization of their spontaneous motility in vitro could give indications about abnormalities of the responsible motor system, namely the cortical actomyosin layer and its interaction with the plasma membrane. Videomicroscopical observations and image data evaluations of keratinocytes spread on glass have revealed typical patterns of peripheral shape changes as rhythmical protrusions and retractions of lamellipodia, periodic waves of ruffles moving towards the cell body and, finally, pulsating or rotating waves of cell protrusions. We present two models of the behavior of actomyosin network taken as a highly viscous reactive and contractive polymer fluid. One describes the dynamics of lamellipodial protrusions transversal to the cell periphery, the other considers a simplified circular model along the whole cell circumference. Simulations of these partial differential equation models reproduce the observed spatio-temporal patterns.