Most cells are organised in space. To function properly, cells often have distinct domains exposed to for example the outer and inner surfaces. This organization in space is referred to as cell polarity, and is a widespread property across kingdoms. In multicellular organisms, polarity domains are often aligned with organismal (front/back, outer/inner, left/right, etc) axes. Furthermore, important decisions, such as the orientation of cell division, are coupled to cell polarity. As such, cell polarity is a fundamental principle connected to normal development and disease. While cell polarity has been studied in substantial detail in single-celled yeasts and in animal models, knowledge is much more limited in the plant kingdom. From genomic analyses, it appears that plants, yeasts and animals do not share proteins in cell polarity pathways, and therefore it is largely unknown whether there are common or distinct molecular mechanisms that drive cell polarisation.
The DIRNDL project builds on recent findings by the principal investigator's team that 1) established the tools for using the early plant embryo as a model system for genetically investigating the establishment of cell polarity in the plant kingdom; 2) offer a set of novel polarity proteins in plants that allow for a proteomics strategy to map the polar proteome and 3) identified a deep protein homology of a shared structural domain that mediates protein polarity across animal and plant kingdoms. The DIRNDL project takes an integrated approach to genetically, proteomically and mechanistically dissect cell polarisation in plants (Arabidopsis and Marchantia).