Chemical approaches for characterising and controlling physiological microtubule composition and dynamics

• Applicant: Dr. Oliver Thorn-Seshold
• Subject Area: Biological and Biomimetic Chemistry
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 400324123

Understanding and manipulating the eukaryotic microtubule cytoskeleton is crucial for decrypting a multitude of cellular processes vital to physiology and pathology: including cell migration, mechanostasis, cell division and embryogenesis, tissue morphogenesis, and neurodegeneration. In order to support the many simultaneous roles that microtubules (MTs) must play, cells must tightly control the structure, remodeling dynamics, and interactions with protein binding partners, of their MTs: all with extreme precision both in time and in space. To elucidate the complexities of the MT cytoskeleton and the many roles that it supports, we therefore require toolsets to probe and modulate MT structure, dynamics, and interactions, which give similar spatial and temporal resolution to that with which cells regulate and use their MTs. Ultimately, these tools will have to succeed in enabling highly precise MT studies in live multicellular organisms. Before this project, no tools had succeeded in these goals. The first funding periods of this project pioneered a range of spatially and temporally precise, light-responsive reagents to manipulate and understand native MT biology. We delivered light-responsive MT-stabilisers (epothilones and taxanes) and MT-destabilisers (colchicinoids) which have been widely distributed for biology studies, and have been applied to longstanding challenges in embryonic development, tissue morphogenesis, and cell migration, including in vivo across a range of live model organisms (fish, fly, frog, etc). To power this has involved developing novel strategies to exploit and harness light applications in vivo, as well as novel photoresponsive chemical scaffolds, which have promoted general progress in the broader field of chemical biology. The final year of project funding will tackle photoresponsive MT modulators that rely on high intrinsic potency and large photo-dependency of bioactivity to enable biological applications in larger model animals; which will be directly applied to study the role that MT stabilisation plays in axonal regeneration. Beyond these direct aims, it is hoped that the urgently-needed, novel layers of spatiotemporal resolution that this project adds onto the traditional paradigms of small molecule inhibitors, and its aims to develop perturbation-free imaging techniques, will open new vistas: for direct research in cytoskeleton biology, for indirect applications studying the many processes and functions that MTs support, and also more generally for the design paradigms that will underlie the chemical biology reagents of the future.

• DFG Programme: Independent Junior Research Groups