About the Project
Intrinsically disordered proteins (IDPs) lack a single well-defined conformation and are instead flexible, exploring multiple possible conformations. This flexibility allows them to interact with multiple binding partners, sometimes simultaneously, in different ways. One example of IDP is Tarp (Translocated actin-recruiting protein), a protein from Chlamydia that is injected into the host cell in the first stages of infection. Once inside the cell, Tarp is capable of interacting with actin monomers and bundles, with vinculin, and with proteins in the signalling cascade involved in remodelling the actin cytoskeleton. Through these multiple interactions, Tarp can alter the actin cytoskeleton using multiple mechanisms to form an actin pedestal which brings Chlamydia into the newly infected cell.
We have recently shown that the WH2-like actin binding region has a partially helical conformation, which is stabilised when bound to an actin monomer. In the full protein, this region leads to the nucleation of actin filaments. We now aim to look at the conformation of other Tarp regions. For instance, Tarp contains a number of tyrosine-rich repeats that are phosphorylated upon cell entry, and then interact with Rac guanine exchange factors, which lead to polymerisation of actin via a signalling cascade. This project will characterise this and other interactions between Tarp and its binding partners.
Disordered proteins are involved in essential regulatory and signalling processes inside cells, often as hubs that bring together multiple signalling pathways, and Tarp is an extreme example of this hub function. A clearer understanding of how Tarp’s flexibility leads to its function will increase our knowledge about the disease processes of Chlamydia, and about the general mechanism of how IDPs perform their role as hub proteins.
The student will receive training in protein expression and purification, protein NMR spectroscopy, and a number of biophysical techniques for studying protein interactions.
For more information on the supervisor for this project, please go here: https://www.uea.ac.uk/chemistry/people/profile/t-blumenschein
Type of programme: PhD
Start date: October 2019
Entry requirements: Chemistry, Physics, Biochemistry or related subjects. The standard minimum entry requirement is 2:1.
Application deadline: 31 May 2019. NB Applications are processed as soon as they are received and the project may be filled before the closing date, so early application.
Funding Notes
This PhD project is offered on a self-funding basis. It is open to applicants with funding or those applying to funding sources. Details of tuition fees can be found at http://www.uea.ac.uk/study/postgraduate/research-degrees/fees-and-funding.
A bench fee is also payable on top of the tuition fee to cover specialist equipment or laboratory costs required for the research. The amount charged annually will vary considerably depending on the nature of the project and applicants should contact the primary supervisor for further information about the fee associated with the project.
References
i) Tolchard, J., Walpole, S. J., Miles, A. J., Maytum, R., Eaglen, L. A., Hackstadt, T., Wallace, B. A. and Blumenschein, T. M. A. (2018) The intrinsically disordered Tarp protein from Chlamydia binds actin with a partially preformed helix. Sci. Reports 8, 1960.
ii) Jewett, T. J., Miller, N. J., Dooley, C. A. and Hackstadt, T. (2010) The conserved Tarp actin binding domain is important for chlamydial invasion. PLoS Pathogens 6, e1000997.
iii) Clifton, D. R., Fields, K. A., Grieshaber, S. S., Dooley, C. A., Fischer, E. R., Mead, D, J., Carabeo, R. A. and Hackstadt, T. (2004) A chlamydial type III translocated protein is tyrosine-phosphorylated at the site of entry and associated with recruitment of actin. Proc. Natl. Acad. Sci. USA 101, 10166-71.
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