One of the most abundant forms of posttranslational modifications of proteins in cells is phosphorylation. This modification is regulated by kinases, reversible and thus highly dynamic. However, our ability to measure and monitor the dynamics of phosphorylation in vivo in real time are currently very limited. Being able to visualise this process in real time would shed light on the fundamental question of where biochemical reactions take place within cells and what their immediate consequences are.
This project aims at generating new tools to address this and to monitor kinase activity and the phosphorylation of kinase substrates of interest. We will exploit nanobodies (single chain camelid antibodies that can be expressed in cells) to develop these tools with the aim to study the phospho-regulation of cell polarity and monitor kinase activity. The lab has developed a suite of tools to study cell polarity in a stem cell model system, the neural stem cells of the fruit fly. These stem cells divide asymmetrically. This means that at each division they polarise to establish a particular subcellular organisation allowing them to sort fate determining molecules to different poles during mitosis. As a consequence, the two resulting daughter cells received each a different set of molecules such that they adopt different cell fates. One will remain a stem cell while the other will become a neuron or glial cell. We have generated tools by CrispR including the ability to use chemical genetics to specifically inhibit kinases with the aim to understand how cell polarity and cell fate are controlled by kinase signalling. The project involves further state of the art imaging technology and implements AI, in form of deep learning using content aware image restoration technology to improve the resolution in time and space when imaging live cells. Finally, the project will use biophysical methods to analyse protein-membrane interactions, to study how substrates behave in response to kinase signalling in vitro and in Drosophila neural stem cells to understand how fate determinants can localise to opposing membrane domains, with the ultimate goal to understand how this process safeguards asymmetrically dividing cells against malignant overgrowth as loss of polarity in stem cells can drive the stem cell lineage into tumorigenesis.