Migration component dynamics and front-rear interplay

• Kritika Sahni
• Dmytro Kotsur
• Georg Dreissen
• Julian Mattes
• Bernd Hoffmann
• Rudolf Merkel
• Galiya Sakaeva

Cell migration is a fundamental process in development and maintenance of multicellular organisms. A coordinated assembly and release of focal adhesion complexes has been reported to be crucial for harmonious cellular movement. In addition, actin and myosinIIA are pivotal components of the cytoskeletal network that work in accord with each other, to facilitate directed cellular movement. In this study, we have analyzed distribution kinetics of Vinculin in nascent FA, mature FA and focal complexes at cell rear. We have also inspected the kinetics of Actin and Non-muscle MyosinIIA in different types of stress fiber structures of EGF stimulated primary human epidermal keratinocytes, using a photoswitchable fluorescent tag, Dendra2. Different focal adhesion complexes have implied varied vinculin exchange kinetics, depending on their location in a polarized cell, indicating divergent levels of front-rear FA kinetics. We have also scrutinized the dynamics of actin and myosin in transversal arcs and ventral stress fibers. Actin polymerization into the ventral stress fiber appears to depends on the retrograde actin flow from the retraction tails behind the cell. However myosinIIA in this fiber, depicts a affinity dependent exchange along the F-actin filament. Actin in transversal arcs show no significant turnover, whereas myosin dynamics was seen to be higher in these stress fiber structures. Our data therefore reflects the dynamics of prime cell migration components and indicates inhomogenous front-rear molecular kinetics.