Characterization of the tick-pathogen interface by quantitative proteomics

Ticks are vectors of pathogens that affect human and animal health worldwide. Ticks and the pathogens they transmit have co-evolved molecular interactions involving genetic traits of both the tick and the pathogen that mediate their development and survival. Proteomics and genomics studies of infected ticks are required to understand tick-pathogen interactions and identify potential vaccine antigens to control tick infestations and pathogen transmission. In this paper, the application of quantitative proteomics to characterize differential protein expression in ticks and cultured tick cells in response to pathogen infection is reviewed. Analyses using (a) two-dimensional differential in gel electrophoresis (DIGE) labeling and (b) protein one-step in gel digestion, peptide iTRAQ labeling, and isoelectric focusing fractionation, both followed by peptide and protein identifications by mass spectrometry resulted in the identification of host, pathogen, and tick proteins differentially expressed in response to infection. Although at its infancy, these results showed that quantitative proteomics is a powerful approach to characterize the tick-pathogen interface and demonstrated pathogen and tick-specific differences in protein expression in ticks and cultured tick cells in response to pathogen infection.