Weizmann Institute of Science (WIN) - Israel

Supervisors: Alexander Bershadsky

Student: Tina Li

8 - Principles of actin cytoskeleton self-organisation

The mechanosensory function of FAs is important for cell shape polarisation and polarised actin filament self-assembly. Spreading of cells confined within cell-sized circular adhesive islands goes through transient formation of radially symmetrical actin arrays, comprising radial (R) and transverse (T) actin fibres, and chiral swirling of the entire system. We propose that contraction of myosin IIA-containing T-fibres generates stresses resulting in centripetal motion of these fibres and force-dependent growth of the R-fibres from FAs. We suggest a combined experimental and theoretical study (TAU) of the mechanisms by which the mechanical properties and topography of external substrates control the orientation of cytoskeletal elements. By tracking fibres over time we will investigate mechanisms that cause spontaneous symmetry breaks resulting in chiral swirling motion of the cytoskeleton. Experimental data from circular adhesive islands will be compared to light-induced small GTPase-dependent cell polarisation and growth factor-induced motility switching in keratinocytes. Results will be incorporated into life time and framework models.