Proteome-wide modulation of S-nitrosylation in Trypanosoma cruzi trypomastigotes upon interaction with the host extracellular matrix

ABSTRACT: Trypomastigotes from Trypanosoma cruzi adhere to the extracellular matrix (ECM) in order to invade mammalian host cells. Incubation of trypomastigotes with ECM leads to a decrease of nitric oxide synthase (NOS) activity and associated post-translational modifications (PTMs). Herein, resin-assisted enrichment of thiols combined with mass spectrometry were employed to map site-specific S-nitrosylated (SNO) proteins from T. cruzi trypomastigotes incubated (MTy) or not (Ty) with ECM. We confirmed the reduction of S-nitrosylation upon incubation with ECM, associated to a rewiring of the subcellular distribution and intracellular signaling pathways of the SNO proteins between MTy and Ty conditions. Forty (~10.7%) and 248 (~66.4%) SNO-peptides were uniquely identified in MTy and Ty, respectively, in addition to 85 peptides (~22.7%) quantified in both conditions. S-nitrosylated proteins were enriched in a wide range of cellular components, including surface membranes and vesicles, and are involved in ribosome, transport, carbohydrate and lipid metabolisms. Of note, we described for the first time nytrosylation of histones H2B and H3 on Cys64 and Cys126, respectively, which is was more abundant in MTy. Additionally, sequence alignment shows that H3 (Cys126) histone is also present in T.b.brucei, but not in L. major, while H2B (Cys64) is absent in both parasites and other higher eukaryotes. Protein-protein interaction networks analyzed by STRING revealed ribosomal proteins, proteins involved in carbon and fatty acid metabolism to be among the enriched protein complexes. Among the SNO ribosomal proteins, 90% were identified and quantified uniquely or upregulated in the Ty fraction. Enzymes involved in oxidoreductase, kinases and phosphatases were identified as nitrosylated and phosphorylated in the same conditions suggesting a crosstalk between these modifications linked to regulation of energy metabolism of T. cruzi in the presence of ECM. Although enzymatic activity of NOS was described in T. cruzi, its identification is elusive. In silico mapping of putative nitric oxide synthase (NOS) gene(s) based on domain architecture identified four putative T. cruzi proteins expressing a putative C-terminal NOS domain: two putative P450 reductases, a putative FMN/FAD containing oxidoreductase and a putative oxidoreductase-protein. Our results provide the first site-specific characterization of S-nitrosylated proteins in T. cruzi linked to the roles of NO in reprogramming parasite cells to invade mammalian hosts.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Trypanosoma Cruzi

DISEASE(S): Chagas Disease

SUBMITTER: Giuseppe Palmisano  

LAB HEAD: Giuseppe Palmisano

PROVIDER: PXD018275 | Pride | 2020-10-27

REPOSITORIES: Pride