Dr M Molodtsov
Dr S Cox
Tuesday, November 12, 2019
Funded PhD Project (Students Worldwide)
A joint Crick-King’s College London funded PhD position for the 2020 programme between the labs of Maxim Molodtsov and Susan Cox.
Intracellular organization, trafficking and chromosome segregation depend on microtubules – long polymers, which physically organize cells and constitute the backbone of the cytoskeleton. Microtubules are stiff hollow polymers approximately 25 nm in diameter that grow by addition of a protein called tubulin. Regulation of microtubule dynamics is essential for cell division and represents one of the major targets for anticancer therapy today. Moreover, mutations in many microtubule-associated proteins lead to neurodegenerative disease and failure to establish connections between microtubule tips and chromosomes leads to aneuploidy - a hallmark of all solid tumours. In order to design better treatments, we need to understand the fundamental physical principles underlying microtubule dynamics and the way it is controlled by microtubule tip binding proteins.
The tips of the growing microtubules interact with proteins that regulate their dynamics, and enable engagement in multiple mechanical processes including force generation and microtubule rearrangement. The interaction between microtubules and tip-binding proteins is defined by structural rearrangements at the microtubule tip. Cryo-electron microscopy showed that microtubules tips adopt a variety of structures including blunt and flared, as well as ends that look like sheets of tubulin. However, these images are taken in a frozen environment. The resolution required to image the end of the microtubule (~5nm) is beyond the limits of current light microscopy methods. In this project new super-resolution microscopy and data analysis techniques will be developed to extract information about movement of molecules at the end of the microtubule, allowing us to gain insight into the fundamental physical principles underlying microtubule dynamics and the role of microtubule tip binding proteins.
As it is not possible to achieve sufficiently high resolution to image the structure on the sub-second timescale we will instead image fluorophores as they move and analyse the shape generated by movement of fluorophores. We will use this information to give both the position and the motion of the fluorophore. Enabling this will require a labelling method which places a fluorophore with a high photon yield very close to the protein, and a fluorophore which can be controlled so only a small proportion of the fluorophores emit light. Initially we will use standard labelling methods, like covalent coupling of small fluorophores to molecules of tubulin, and later use more sophisticated techniques such as photoactivatable proteins and DNA-PAINT technology.
Initially, computer simulations will be developed to determine the optical parameters required to achieve sufficient spatial and temporal resolution to determine the structure and dynamics of the microtubule ends. The student will also perform experiments with recombinant microtubules and analyse data. These approaches will provide fundamental mechanistic insights into how microtubule polymers grow and how their dynamics is regulated. At later stages of the project, we will aim to image microtubule dynamics in vivo, thus getting mechanistic insight into how microtubule dynamics is regulated in live cells. Methods developed in this project will also lend themselves to address much broader questions in cell biology and beyond, which require real-time single-molecule imaging.
The project is highly interdisciplinary and would therefore be suitable for those with a good first degree in biophysics, physics, computer science, engineering, chemistry or biology. Some prior experience in scientific programming would be highly desirable, as the project will involve a substantial amount of simulation and image analysis. Experience of fluorescence microscopy would be beneficial. A strong interest in interdisciplinary work, biological questions and quantitative methods are essential.
Talented and motivated students passionate about doing research are invited to apply for this PhD position. The successful applicant will join the Crick PhD Programme in September 2020 and will register for their PhD at one of the Crick partner universities (Imperial College London, King’s College London or UCL).
Applicants should hold or expect to gain a first/upper second-class honours degree or equivalent in a relevant subject and have appropriate research experience as part of, or outside of, a university degree course and/or a Masters degree in a relevant subject.
APPLICATIONS MUST BE MADE ONLINE VIA OUR WEBSITE (ACCESSIBLE VIA THE ‘APPLY NOW’ LINK ABOVE) BY 12:00 (NOON) 13 NOVEMBER 2019. APPLICATIONS WILL NOT BE ACCEPTED IN ANY OTHER FORMAT.
Successful applicants will be awarded a non-taxable annual stipend of £22,000 plus payment of university tuition fees. Students of all nationalities are eligible to apply.
1. McIntosh, J. R., Molodtsov, M. I. and Ataullakhanov, F. I. (2012)
Biophysics of mitosis.
Quarterly Reviews of Biophysics 45: 147-207. PubMed abstract
2. Molodtsov, M. I., Mieck, C., Dobbelaere, J., Dammermann, A., Westermann, S. and Vaziri, A. (2016)
A force-induced directional switch of a molecular motor enables parallel microtubule bundle formation.
Cell 167: 539-552 e514. PubMed abstract
3. Marsh, R. J., Pfisterer, K., Bennett, P., Hirvonen, L. M., Gautel, M., Jones, G. E. and Cox, S. (2018)
Artifact-free high-density localization microscopy analysis.
Nature Methods 15: 689-692. PubMed abstract
4. Cox, S., Rosten, E., Monypenny, J., Jovanovic-Talisman, T., Burnette, D. T., Lippincott-Schwartz, J., . . . Heintzmann, R. (2012)
Bayesian localization microscopy reveals nanoscale podosome dynamics.
Nature Methods 9: 195-200. PubMed abstract