Oral Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

Analysis of In vivo Arginine-glycosylation targets of the NleB/SseK family of effectors reveals discrete effector substrate specificities (#106)

Nichollas Scott 1 , Joshua Newson 1 , Cristina Giogha 2 , Jaclyn Pearson 2 , Elizabeth Hartland 2
  1. Department of Microbiology and Immunology, University of Melbourne, Melbourne, VICTORIA, Australia
  2. Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Australia

Effector glycosyltransferases are a growing class of secreted bacterial proteins which subvert normal cellular functions through the modification of host proteins with carbohydrates. Within the enteric pathogens (enteropathogenic Escherichia coli (EPEC), Salmonella enterica serovar Typhimurium and Citrobacter rodentium) the NleB/SseK family of effector glycosyltransferases mediate the glycosylation of arginine residues. The archetype of this family, NleB1 of EPEC, has been shown to modify multiple death-domain-containing proteins responsible for extrinsic apoptosis, with N-acetylglucosamine under ectopic expression/in vitro conditions. Using an Arginine-GlcNAcylation affinity proteomic approach we recently showed that under in vivo condition NleB1 preferentially modifies a single protein, Fas-associated death domain protein (FADD), during infection (1). Building on this work we have now investigated the specificity and substrate repertoire of two homologues of NleB1, SseK1 and SseK3, from Salmonella enterica serovar Typhimurium during bacterial infections. We demonstrate that in contrast to recent ectopic expression studies during S. Typhimurium infection the SseK1 and SseK3 effectors target discrete death domain proteins in the TNF and TRAIL signaling pathways (2). We reconciled the difference between our finding and previous studies by demonstrating that the over expression of the NleB/SseK family of effectors leads to ramped modification of both host and bacterial substrates. Taken together, these findings demonstrate that the NleB/SseK effectors can act far more promiscuously than previously thought when overexpressed, but under endogenous infections each effector antagonise different components of death receptor signalling.


  1. Scott, N. E., Giogha, C., Pollock, G. L., Kennedy, C. L., Webb, A. I., Williamson, N. A., Pearson, J. S., and Hartland, E. L. (2017) The bacterial arginine glycosyltransferase effector NleB preferentially modifies Fas-associated death domain protein (FADD). The Journal of biological chemistry 292, 17337-17350
  2. Newson, J. P., Scott, N. E., Yeuk Wah Chung, I., Wong Fok Lung, T., Giogha, C., Gan, J., Wang, N., Strugnell, R., Brown, N. F., Cygler, M., Pearson, J. S., and Hartland, E. L. (2019) Salmonella effectors SseK1 and SseK3 target death domain proteins in the TNF and TRAIL signaling pathways. Molecular & cellular proteomics : MCP