BIOMECHANICS OF ACTOMYOSIN MEDIATED MOTIL ITY IN KERATINOCYTES

Migration of epidermal skin cells, keratinocytes, plays an important r ole in processes as wound healing or melanoma formation. Thus, charact erization of their spontaneous motility in vitro could give indication s about abnormalities of the responsible motor system, namely the cort ical actomyosin layer and its interaction with the plasma membrane. Vi deomicroscopical observations and image data evaluations of keratinocy tes spreaded on glass have revealed typical patterns of peripheral sha pe changes as rhythmical protrusions and retractions of lamellipodia, periodic waves of ruffles moving towards the cell body and, finally, p ulsating or rotating waves of cell protrusions. We present two models of the behavior of actomyosin network taken as a highly viscous reacti ve and contractive polymer fluid. One describes the dynamics of lamell ipodial protrusions transversal to the cell periphery, the other consi ders a simplified circular model along the whole cell circumference. S imulations of these partial differential equation models reproduce the observed spatio-temporal patterns.