Berlin 2018 – scientific programme
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BP: Fachverband Biologische Physik
BP 3: Cell Adhesion and Migration, Multicellular Systems I
BP 3.10: Talk
Monday, March 12, 2018, 12:15–12:30, H 2013
Universal kinetics for the engagement of mechanosensing pathways in cell adhesion — •Samuel Bell and Eugene M. Terentjev — Cavendish Laboratory, 19 JJ Thomson Ave, Cambridge, CB3 0HE, United Kingdom
When plated onto a 2D substrate, cells will adhere and then spread, before becoming polarised. It is well known that cells plated onto surfaces with lower elastic moduli spread to a smaller final area than on stiffer surfaces. We studied the time of onset of spreading for two cell lines, endothelial cells (EA.hy927) and fibroblasts (NIH/3T3) onto a large range of substrates, and, remarkably, found that the dynamics of early spreading are the same over a wide range of stiffnesses (460Pa-30GPa). Instead, the dynamics were found to be greatly influenced by temperature. The long-time probability of onset displays an exponential activation, P(t)∼ exp(−kt) for both cell lines, with an Arrhenius-type rate constant k∝exp(−G/kBT). The energy barrier was found for both cell lines to be G≈19kcal/mol, and tallies with a recent study on the activation of focal adhesion kinase (FAK). Further to this, the short-time probability of having spread by time t follows a universal power law scaling, much as in nucleation theory, Q(t)∝ t5. This is evidence for the onset of spreading being governed by the assembly of focal complexes with 5 major steps of building followed by FAK activation.