Control of type III-mediated virulence by a key bacterial signal (MALONE_J17DTP1)

Lead Research Organisation: University of East Anglia
Department Name: Graduate Office

Abstract

The bacterial Type III Injectisome T3I is a needle-like structure that delivers effectors and toxins directly into host cells. The T3I plays a crucial role in pathogenicity and host infection in many bacteria, including the major human and plant pathogens P. aeruginosa and P. syringae. We recently showed that a crucial component of the T3I; the export ATPase complex, binds specifically to the signalling molecule cyclic-di-GMP (cdG), a key regulator of bacterial behaviour associated with virulence control in many bacterial pathogens.
Defining the relationship between the T3I and cdG is key to understanding T3I regulation during bacterial infections.

In this project, we will use a combination of genetics, biochemistry and structural biology to define how cdG-binding controls the T3Is of P. aeruginosa and P. syringae. The student will construct specific cdG-binding mutants in both species, and characterise them for virulence and effector protein export. These experiments will be supported by in-depth biochemical analysis of purified ATPase proteins. The emerging model for cdG-ATPase control will be refined by structural characterisation by cryo-EM and X-ray crystallography.
 
Description This project work is still on-going. What has been shown up to this point is that an common signalling molecule known as cyclic-di-GMP is important for regulating virulence in Pseudomonas syringae. This regulatory control is achieved by the CdG binding to HrcN, an ATPase protein that drives the energetic function of the Type III secretion system (a bacterial nanomachine that facilitates infection). By altering the predicted binding site and the CdG binding interaction, virulence of plant targets is also impacted. Current work is exploring this binding interaction to unpick the mechanism for exactly how this regulation occurs.
Exploitation Route This project has several future avenues that can be explored as part of the pathway to impact. This project specifically looks at the bacteria genus Pseudomonas however in future, a key area of exploration by research scientists would be to see how well conserved this system is across other species. Bioinformatic analysis shows that similar Type III secretion system ATPase proteins exist, however it is still unclear whether their mechanisms of action are different. Increased knowledge of the ATPase:CdG binding interaction can also lead to several future applied projects. This binding interaction can potentially be used as a target for antibiotic discovery to control bacterial virulence in future.
Sectors Agriculture, Food and Drink,Chemicals,Education,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology
 
Description I have communicated my research to the public in a variety of settings including public lectures, outreach events and written articles. By communicating my research in an accessible way to a wide variety of audiences, I have helped to increase awareness and understanding of my particular research area. This ultimately has society and cultural benefits within the local community.
First Year Of Impact 2017
Sector Education,Other
Impact Types Cultural,Societal
 
Description Public talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact I have given a variety of public talks to a wide variety of audiences where I describe my research area, my findings and how this fits in to the context of wider society. This includes at the Norwich Science Festival.
Year(s) Of Engagement Activity 2018,2019,2020