Enjoy our new review!

Going with the flow: insights from Caenorhabditis elegans zygote polarization

(Gascon et al., 2020)

Cell polarity is the asymmetric distribution of cellular components along a defined axis. Polarity relies on complex signalling networks between conserved patterning proteins, including the PAR (partitioning defective) proteins, which become segregated in response to upstream symmetry breaking cues. Although the mechanisms that drive the asymmetric localization of these proteins are dependent upon cell type and context, in many cases the regulation of actomyosin cytoskeleton dynamics is central to the transport, recruitment and/or stabilization of these polarity effectors into defined subcellular domains. The transport or advection of PAR proteins by an actomyosin flow was first observed in the Caenorhabditis elegans zygote more than a decade ago. Since then a multifaceted approach, using molecular methods, high-throughput screens, and biophysical and computational models, has revealed further aspects of this flow and how polarity regulators respond to and modulate it. Here, we review recent findings on the interplay between actomyosin flow and the PAR patterning networks in the polarization of the C. elegans zygote. We also discuss how these discoveries and developed methods are shaping our understanding of other flow-dependent polarizing systems.

Congratulations all for such a nice paper!

Morphogenetic degeneracies in the actomyosin cortex

Naganathan et al., (2018)

Abstract. One of the great challenges in biology is to understand the mechanism by which morphogenetic processes arise from molecular activities. We investigated this problem in the context of actomyosin-based cortical flow in C. elegans zygotes, where large-scale flows emerge from the collective action of actomyosin filaments and actin binding proteins (ABPs). Large-scale flow dynamics can be captured by active gel theory by considering force balances and conservation laws in the actomyosin cortex. However, which molecular activities contribute to flow dynamics and large-scale physical properties such as viscosity and active torque is largely unknown. By performing a candidate RNAi screen of ABPs and actomyosin regulators we demonstrate that perturbing distinct molecular processes can lead to similar flow phenotypes. This is indicative for a ’morphogenetic degeneracy’ where multiple molecular processes contribute to the same large-scale physical property. We speculate that morphogenetic degeneracies contribute to the robustness of bulk biological matter in development.


Check out our paper in Dev Cell !

aPKC Cycles between Functionally Distinct PAR Protein Assemblies

to Drive Cell Polarity

Rodriguez et al. (2017)

Congrats and thank you all for the hard work

Thanks to Edwin Munro for a really clear review of our work in collaboration with Goehrings’ lab and that of Dickinson et al. (2017) and Wang et al. (2017) , all showing how PAR protein oligomerization can dynamically couple protein diffusion and transport by cortical flow to control kinase activity gradients and polarity in the C. elegans zygote.

Protein Clustering Shapes Polarity Protein Gradients

Munro (2017)