Sweet and Sour Ehrlichia: Glycoproteomics and Phosphoproteomics Reveal New Players in Ehrlichia ruminantium Physiology and Pathogenesis
|Author(s)||Marcelino Isabel1, 2, 3, Colome-Calls Nuria4, Holzmuller Philippe2, 5, Lisacek Frederique6, 7, 8, Reynaud Yann3, Canals Francesc4, Vachiery Nathalie2, 5|
|Affiliation(s)||1 : UMR ASTRE, CIRAD, Petit Bourg, Guadeloupe, France.
2 : Univ Montpellier, INRA, CIRAD, ASTRE, Montpellier, France.
3 : Inst Pasteur Guadeloupe, Unite TReD Path Transmiss Reservoirs & Diversite, Les Abymes, Guadeloupe, France.
4 : VHIO, Prote Lab, Barcelona, Spain.
5 : UMR ASTRE, CIRAD, Montpellier, France.
6 : Swiss Inst Bioinformat, Proteome Informat, Geneva, Switzerland.
7 : Univ Geneva, Comp Sci Dept, Geneva, Switzerland.
8 : Univ Geneva, Sect Biol, Geneva, Switzerland.
|Source||Frontiers In Microbiology (1664-302X) (Frontiers Media Sa), 2019-03 , Vol. 10 , P. 450 (18p.)|
|WOS© Times Cited||5|
|Keyword(s)||Ehrlichia ruminantium, phosphoproteins, S/T/Y phosphorylation, N-glycoproteins, O-GIcNAcylated proteins, bacteria physiology, pathogenesis|
|Abstract||Unraveling which proteins and post-translational modifications (PTMs) affect bacterial pathogenesis and physiology in diverse environments is a tough challenge. Herein, we used mass spectrometry-based assays to study protein phosphorylation and glycosylation in Ehrlichia ruminantium Gardel virulent (ERGvir) and attenuated (ERGatt) variants and, how they can modulate Ehrlichia biological processes. The characterization of the S/T/Y phosphoproteome revealed that both strains share the same set of phosphoproteins (n = 58), 36% being overexpressed in ERGvir. The percentage of tyrosine phosphorylation is high (23%) and 66% of the identified peptides are multi-phosphorylated. Glycoproteomics revealed a high percentage of glycoproteins (67% in ERGvir) with a subset of glycoproteins being specific to ERGvir (n = 64/371) and ERGatt (n = 36/343). These glycoproteins are involved in key biological processes such as protein, amino-acid and purine biosynthesis, translation, virulence, DNA repair, and replication. Label-free quantitative analysis revealed over-expression in 31 proteins in ERGvir and 8 in ERGatt. While further PNGase digestion confidently localized 2 and 5 N-glycoproteins in ERGvir and ERGatt, respectively, western blotting suggests that many glycoproteins are O-GIcNAcylated. Twenty-three proteins were detected in both the phospho- and glycoproteome, for the two variants. This work represents the first comprehensive assessment of PTMs on Ehrlichia biology, rising interesting questions regarding ER-host interactions. Phosphoproteome characterization demonstrates an increased versatility of ER phosphoproteins to participate in different mechanisms. The high number of glycoproteins and the lack of glycosyltransferases-coding genes highlight ER dependence on the host and/or vector cellular machinery for its own protein glycosylation. Moreover, these glycoproteins could be crucial to interact and respond to changes in ER environment. PTMs crosstalk between of O-GIcNAcylation and phosphorylation could be used as a major cellular signaling mechanism in ER. As little is known about the Ehrlichia proteins/proteome and its signaling biology, the results presented herein provide a useful resource for further hypothesis-driven exploration of Ehrlichia protein regulation by phosphorylation and glycosylation events. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium with the data set identifier PXDO12589.|