PhD Research Project: Cellular mechanisms underlying human infection by the intestinal bacterial pa

Understanding the molecular basis of host-pathogen interactions has never been more important given the health threat posed to humans and farmed food chain animals by bacterial pathogens that continue to develop multidrug resistance. Enterohaemorrhagic Escherichia coli (EHEC) 0157:H7 is an important enteric food-borne pathogen causing life-threatening haemorrhage colitis and haemolytic ureic syndrome in humans. Currently no treatment is available for EHEC infections. Advancing our knowledge of the EHEC virulence mechanisms has the potential to combat disease by speeding the development of anti-infectives and broadening the scope for therapeutic intervention.

To colonise the human intestine EHEC assembles a syringe-like Type 3 Secretion System that injects a cocktail of virulence effector proteins into host cells, which facilitate bacterial colonisation, survival and immune evasion in infected hosts (e.g. see Humphreys et al 2016). The effectors hijack cellular signalling pathways, including those involved in controlling the actin cytoskeleton, vesicle trafficking and cell survival. To combat this disease we need to know the host targets of the EHEC virulence effectors and the mechanisms by which they hijack cellular processes during infection.

We are looking for an enthusiastic and ambitious PhD candidate to investigate interactions between EHEC and mammalian host cells at the Department of Biomedical Science. The student will receive interdisciplinary training in a broad range of techniques, gaining valuable laboratory and research scientist experience, particularly in pathogen and cell biology, and will be an integral part of our research group and a collegiate Department.

The PhD project will combine pathogen genetics and molecular biology to engineer mutant strains of EHEC and recombinant virulence effectors. The recombinant strains will be used to identify pivotal virulence effectors and host cell targets (e.g. of the actin cytoskeleton, vesicle trafficking and/or cell survival) by performing high-throughput infection screens on cultured mammalian cells at the Sheffield RNAi Screening Facility. The screen will be used as a springboard to elucidate novel disease mechanisms by taking advantage of established protein-protein biochemical techniques, mass spectrometry, and cutting-edge fluorescence imaging microscopes at the Wolfson Imaging Light Microscopy Facility (e.g. super-structural resolution, confocal microscopy).

Funding Notes

Applications from self-funded students or students with secured funding are also welcome.

Entry requirements
First class or upper second 2(i) in a relevant subject. To formally apply for a PhD Studentship, you must complete the University's application form using the following link: http://www.sheffield.ac.uk/bms/prospective_pg/how_to_apply

*All applicants should ensure that both references are uploaded onto their application as a decision will be unable to be made without this information*.

References

http://www.sheffield.ac.uk/bms/research/humphreys/

1. Humphreys D. Singh V, Koronakis V. (2016). Inhibition of WAVE Regulatory Complex activation by a bacterial virulence effector counteracts pathogen phagocytosis. Cell Reports, in press.

2. Humphreys D, Davidson AC, Hume PJ, Makin LE, Koronakis V. (2013) Arf6 coordinates actin assembly through the WAVE complex, a mechanism usurped by Salmonella to invade host cells. Proceedings of the National Academy of Sciences of the United States of America. 110(42):16880-16885. PMID: 24085844

3. Humphreys D, Davidson AC, Hume PJ, Koronakis V. (2012) Salmonella SopE and host GEF ARNO cooperate to recruit and activate WAVE to trigger bacterial invasion. Cell Host & Microbe 11, 129-39. PMID: 22341462

4. Smith, K., Humphreys, D., Hume, P.J., and Koronakis, V. (2010) Enteropathogenic Escherichia coli recruits the cellular inositol phosphatase SHIP2 to regulate actin-pedestal formation.
Cell Host & Microbe 7, 13-24. PMID: 20114025