Dresden 2014 – scientific programme
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BP: Fachverband Biologische Physik
BP 33: Active cell and tissue mechanics (focus session) I
BP 33.8: Talk
Thursday, April 3, 2014, 12:00–12:15, HÜL 386
PAR dependent regulation of mechanical activity of the actomyosin cortex in C. elegans zygotes — •Peter Gross1,2, Vijay Krishnamurthy2,3, Nathan Goehring4, Justin Bois5, and Stephan Grill1,2,3 — 1MPI-CBG, Dresden, Germany — 2BIOTEC, TU Dresden — 3MPI-PKS, Dresden, Germany — 4London Research Institute, UK — 5UCLA, Los Angeles, CA
The interplay between biochemistry and cell mechanics is critical for a broad range of morphogenetic changes. A prominent example hereof is the emergence of cell polarity during the early embryogenesis of C. elegans, resulting in a patterned state of the membrane-associated PAR polarity proteins. Crucial for the robust emergence of the patterned state are large-scale flows in the membrane-associated actomyosin cortex, which are observed concomitantly with the emergence of PAR polarization. The coupling of biochemistry and large-scale transport via cortical flows, driving this mechanochemical patterning processes, remain poorly understood. We demonstrate a regulatory role of the PAR polarity domains on actomyosin cortex contractility, which can generate cortical flows at the onset of polarization. We quantify the spatial regulation of non-muscle myosin II (nmy-2) turnover in the cortex by a combination of Fluorescence Recovery After Photobleaching (FRAP) and RNA interference (RNAi). Furthermore we present a theoretical description of this process in the framework of active fluids combined with PAR biochemistry in a coupled reaction-diffusion-contraction-advection approach, and show that this model captures all aspects of the dynamics of the PAR polarization process quantitatively.