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BP: Fachverband Biologische Physik

BP 27: Cell Mechanics II

BP 27.7: Vortrag

Donnerstag, 15. März 2018, 11:45–12:00, H 1028

Induction of cytoplasmic flows reveals: asymmetric cell division is a digital decision based on gradually varying PAR polarization states — M. Mittasch¹, M. Nestler², P. Groß³, A. Fritsch¹, M. Kar¹, S. Grill³, A. Voigt², and •M. Kreysing¹ — ¹MPI-CBG — ²Dept. of Mathematics, TUD — ³Biotec, TUD (all Dresden)

Throughout the last decades, access to genetic perturbations boosted our molecular-level understanding of cell biological processes. However, it was suggested that the spatio-temporal organization of cells and developing embryos also depends on physical transport processes, which remains an experimental challenge to confirm.

Here we present *Focused light induced cytoplasmic streaming* (FLUCS) which enables the dynamic control of cytoplasmic flows in cells and developing embryos via thermoviscous expansion phenomena (Weinert & Braun, J Appl Phys 2008). FLUCS allows to systematically dissect the role of flows during PAR polarization. We find that i) cytoplasmic flows towards the membrane drive PAR loading locally, ii) cytoplasmic flows parallel to the membrane induce cortical flows. iii) Control over cortical flows enables to move pre-established PAR domains. iv) We find that small displacements of PAR domains are self-corrected and cells divide normally. v) For rotations beyond 90 degrees, however, we observe a flip of the PAR defined body axis, followed by inverted asymmetric cell divisions. Our results suggest that asymmetric cell division is a digital decision based on a gradually varying PAR polarization states. Ref: Mittasch et al (accepted).