Background

Multicellular organisms develop by a tightly regulated sequence of cell divisions, to form all the cell types needed to build a variety of tissues and organs. This process requires uneven distribution of components, called cell polarity. Deficiencies in cell polarity regulators affect development and cause lethality in animals. In plants, the underlying molecular mechanisms of cell polarity are mostly unknown. An important limitation in studying this fundamental process is that the genes involved are likely either essential or functionally redundant, limiting the power of genetic approaches.

Project description

Therefore, I am using proteomics in this project instead, which allows the study of proteins in vivo with minimal to no disruption of their function. I am studying the Arabidopsis SOSEKI1 protein, a recently identified ‘molecular compass’ that consistently marks the same corner of each cell relative to the plant body axes and is activated during de novo polarity axis formation. SOSEKI1 forms a polar protein scaffold through self-polymerization, recruiting downstream effectors. While polar complex assembly is a recurring phenomenon in polarity systems, our understanding about how these form and function is limited. In this project, I am addressing 1) how SOSEKI1 gene expression is regulated, 2) where and in which oligomerization state protein-protein interactions take place, 3) how SOSEKI1 controls on cellular organization and 4) how novel identified regulators and interactors affect plant development. Through proteomic and functional investigation of this novel polarity protein and its interactors, I aim to identify key mechanisms and principles in cell polarization that are essential to regulated plant development, in collaboration with the ongoing work on cell polarity within the group.