Understanding the function of microtubule-associated signalling networks in health and disease: role of adaptor proteins in network assembly

Microtubules (MTs) are essential for the regulation of key processes in eukaryotic cells, in particular cargo transport, cell division and migration. At the heart of these cellular processes are dynamic assemblies of MT plus-end tracking proteins (+TIPs). They guide MTs precisely to different areas in cells, and then selectively trigger specific responses "on arrival". +TIP-network assembly is governed by adaptor proteins that contain a small set of short protein interaction motifs (SxIP, EEY and basic-S/P-), embedded into intrinsically disordered regions however, this story is far from complete. Most of the research is focused on individual components, and little quantitative analysis is conducted. As a result, predictions from current models are unreliable. This project is an integral part of an on-going study to develop a comprehensive, multi-component model of +TIP signalling networks. Mutations of adaptor proteins in cancer contributes to disease progression and metastasis, demonstrating their critical role and the justification for more comprehensive research.

Using NMR, X-ray crystallography and ITC we will solve structures of the adaptor protein complexes and define thermodynamic characteristics of the main interactions within the plus-end networks that are currently uncharacterised. Primarily we will focus on the SxIP, EEY and basic-S/P-motifs that interconnect the core of the networks. We will also monitor the networks in live cells with high-resolution fluorescent microscopy and use cell-permeable structure-based peptide inhibitors to modulate their characteristics by disrupting specific interactions. These changes will be correlated with the effects on migration and proliferation of normal and cancer cells to define the contributions of specific proteins. With engineered cell substrates we will modulate cell environment to emulate healthy and pathological tumour and ageing tissues, thus defining the ability of cells to react to the environmental changes. Joining all the information together we hope to identify critical components of the signalling networks and test their potential as drug targets.