Open Access Te Herenga Waka-Victoria University of Wellington
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Identifying Human Host Cell Protein Targets of the Bartonella Effector Protein (Bep) Fic Domains

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posted on 2021-11-15, 21:22 authored by Trounson, Vaughan

The genus Bartonellae represents an increasing number of emerging bacterial pathogens that utilises an unusual infection strategy, parasitising the red blood cells of their mammalian host. The most common species to infect humans are B. henselae and B. quintana. B. henselae is transmitted between cats by the cat flea, although occasionally infects humans via cat scratches or bites, causing cat-scratch disease (CSD). CSD is characterised by enlarged tender lymph nodes and fever. B. henselae also infects the endothelial cells of both its hosts; likely a factor in disease progression. B. quintana, the cause of trench fever during WWI, is spread people by the body louse. Trench fever is characterised by relapsing fever, headache, and bone pain. B. quintana is also able to infect human endothelial cells. These bacteria secrete a range of Bartonella effector proteins (Beps) via a Type IV secretion system, directly into endothelial cells, subverting host cell processes and resulting in internalisation of the bacteria.  Beps have a range of functions, many of which are not fully characterised. B. henselae secretes three Beps (BepA-C) that contain a filamentation induced by cAMP (Fic) domain and a Bartonella Intracellular Delivery (BID) domain, with BepA being the best studied. BepA’s BID domain is responsible for intracellular delivery as well as inhibition of apoptosis by the host cell, however the exact function of the Fic domain remains unknown. Fic-containing bacterial toxins catalyse the transfer of an AMP moiety from ATP onto a host cell protein. This AMPylation frequently inactivates these proteins resulting in disrupted host cell processes and cytotoxicity. BepA has previously been shown to possess AMPylation activity, although the host target protein(s) are unknown. Evidence suggests that these proteins are novel targets.  The aim of this study was to create protein constructs containing these Fic domains, and to develop techniques to identify the host cell target proteins post AMPylation. To this end, both a fluorescent ATP analogue and a fluorescent click chemistry based approach were utilised. While no target protein was identified, a basic methodology was developed for protein production and target protein identification that could be further developed.


Copyright Date


Date of Award



Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Biomedical Science

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level


Degree Name

Master of Biomedical Science

Victoria University of Wellington Unit

Centre for Biodiscovery

ANZSRC Type Of Activity code


Victoria University of Wellington Item Type

Awarded Research Masters Thesis



Alternative Title

Identifying Human Host Cell Protein Targets of the Bep Fic Domains

Victoria University of Wellington School

School of Biological Sciences


MacKichan, Joanna