Poster Presentation 24th Annual Lorne Proteomics Symposium 2019

Multi-omics analysis of a nutrient transport protein required for full virulence in Campylobacter jejuni   (#95)

Lok Man 1 2 , Joel A. Cain 1 2 , William Klare 1 2 , Nestor Solis 3 4 , Pamela Soh 1 , Zeynep Sumer-Bayraktar 1 2 , Paula Niewold 2 5 , Ashleigh Dale 1 2 , Stuart J. Cordwell 1 2 5 6
  1. School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
  2. Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
  3. School of Molecular Bioscience, University of Sydney, Sydney, NSW, Australia
  4. Centre for Blood Research, University of British Columbia, Vancouver, Canada
  5. Discipline of Pathology, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
  6. Sydney Mass Spectrometry, The University of Sydney, Sydney, NSW, Australia

Campylobacter jejuni is the leading cause of bacterial gastroenteritis in the developed world. Infection is predominantly caused by the consumption of undercooked or poorly prepared poultry. C. jejuni exists mainly as a commensal within the intestines of chickens, but is pathogenic in humans. While the mechanism of this difference is unknown, factors such as motility and nutrient uptake are significant in the host-pathogen nexus. C. jejuni is considered assaccharolytic and primarily utilizes amino and organic acids as carbon sources, with only some strains able to utilize fucose. We conducted label-based LC-MS/MS proteomics of C. jejuni NCTC11168O to identify proteins associated with growth in environments that mimic host conditions (e.g. deoxycholate, iron limitation, presence of mucin). We quantified 1561 proteins, equating to ~93% of the predicted C. jejuni proteome. The most significantly induced protein (mean 4.6-fold induction) was the product of the cj0025 gene, which has been annotated as a ‘putative C4-dicarboxylate transporter’. Deletion of cj0025 resulted in reduced C. jejuni motility, increased susceptibility to polymyxin B, and reduced biofilm formation. Human epithelial cell infection assays confirmed Δcj0025 C. jejunidemonstrated significantly reduced adherence and invasion. To determine the function of Cj0025, metabolomic profiles of media inoculated with C. jejuni wild-type or Δcj0025 were compared, with focus on the uptake of amino acids and Krebs cycle intermediates. These assays showed that Δcj0025 was capable of utilizing all amino and organic acids commensurate with the wild-type. Sequence similarity to a family of bacterial cystine (Cys-Cys) transporters was determined and medium cystine levels were significantly maintained in Δcj0025 mutants compared with wild-type. Growth supplemented with a toxic mimic of cystine, selenocystine, significantly inhibited wild-type growth, but did not affect Δcj0025. We confirm that Cj0025 is a cystine transporter, which we have named TcyP consistent with the nomenclature of homologous proteins.