Identification of protein interactions between Salmonella and the mammalian host during intracellular survival

Andrea Briones Gomez

Research output: ThesisDoctoral Thesis

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Salmonella typhimurim is the major cause of gastroenteritis in the developed and developing world. This research focuses on the hypothesis that the Salmonella atypical fimbriae (Saf) plays an important role in attachment and re-infection of cells. Salmonella atypical fimbriae (Saf) is mainly composed of several SafA subunits and one SafD unit at the tip of the SafA polymer. SafA's sequence is variable within Salmonella strains but SafD's is not, indicating that SafD is most likely a conserved adhesin, whereas SafA is involved in host specificity.
The Saf fimbriae was studied by designing recombinant dual tagged protein SafA' (GST-SafA-6xHis). This was immobilised in a repertoire of systems until finding a suitable one that would allow us to study protein-protein interactions between Salmonella and the mammalian host. Finally, any SafA-6xHis binding partners identified in the large intestine affinity-enrichments were identified by mass spectrometry.
The experiments were performed with a variety of negative controls, including GST, BSA, cleaved SafA' (SafA-6xHIs), SafA’ (GST-SafA-6xHis), among others to identify specific interactions. The analysis was carried out with Scaffold, a bioinformatics tool that increases confidence in protein identification reports through the use of several statistical methods. A stringent analysis was performed, leading to the identification of five SafA-6xHis interacting proteins.
Whilst hypothetical, a role for the Saf fimbriae other than in surface attachment is suggested on the basis of the results. Different functions for the Saf fimbriae that will allow Salmonella to modulate crucial events during the infection process are discussed: mitochondrial apoptosis, effect on the transcription of host genes, neutrophil induced cell death and the binding to host transmembrane proteins.
Original languageEnglish
Awarding Institution
  • Royal Holloway, University of London
  • Devoto, Alessandra, Supervisor
  • Soloviev, Mikhail, Supervisor
  • Bindschedler, Laurence , Supervisor
Award date1 May 2017
Publication statusUnpublished - 1 Sept 2016


  • Salmonella
  • SafA
  • protein
  • mass spctrometry

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