Identification of Novel Host Interactors of Effectors Secreted by Salmonella and Citrobacter

Abstract

During infection, pathogenic bacteria face an adverse environment of factors driven by both cellular and humoral defense mechanisms. To help evade the immune response and ultimately proliferate inside the host, many bacteria evolved specialized secretion systems to deliver effector proteins directly into host cells. Translocated effector proteins function to subvert host defense mechanisms. Numerous pathogenic bacteria use a specialized secretion system called type III secretion to deliver effectors into the host cell cytosol. Here, we identified 75 new host targets of Salmonella and Citrobacter effectors, which will help elucidate their mechanisms of action.

The specific metabolome profiling of patients infected by SARS-COV-2 supports the key role of tryptophan-nicotinamide pathway and cytosine metabolism

“…Omics approaches in host cells infected by this virus may complete the data about the dynamics of metabolism-inflammation link, as well as the short and long term consequences on cells homeostasis. Our findings open the perspective of omics combination with proteomics and lipidomics to expand the metabolic coverage 43 .…”

The Plasmodium falciparum exported protein PF3D7_0402000 binds to erythrocyte ankyrin and band 4.1

“…After cooling to room temperature, cysteine residues were alkylated by adding 2 μL of 400 mM iodoacetamide and incubating at 37° C in the dark for 1 h. Proteins were digested overnight at 37° C by adding 140 μL of 3.5 ng/μL trypsin dissolved in a buffer containing 50 mM NH 4 HCO 3 and 1.3 mM CaCl 2 . The digested peptides were loaded onto C18 microspin columns; centrifuged according to the manufacturer’s instructions; the column was equilibrated by flushing twice with 100 μL of 100 % methanol and twice with 100 μL of 0.1 % trifluoroacetic acid (TFA), then the sample was loaded and the column was washed three times with 100 μL of 5 % acetonitrile (ACN)/0.1 % TFA before eluting the peptides in 100 μL 80% ACN/0.1% TFA [41, 42]. After drying in a SpeedVac, the samples were resuspended in 20 μL 0.1% formic acid and stored at −20° C. Samples were subjected to LC-MS/MS analysis on an NanoAcquity UPLC (Waters) connected to a Q Exactive Plus mass spectrometer (Thermo Fisher Scientific).…”

Keeping in Touch with Type-III Secretion System Effectors: Mass Spectrometry-Based Proteomics to Study Effector–Host Protein–Protein Interactions

“…Interestingly, while for some Salmonella enterica serovar Typhimurium ( S Tm) effectors, e.g., GtgA and SseI, 25, and 14 confident EH-PPIs, respectively, were retrieved, for four other effectors (CigR, PipB2, SifA, and SssA) no host interactors were found. In contrast, D’Costa and colleagues screened five Salmonella T3Es, including PipB2 and SifA, for human protein interactors using AP-MS in a cellular context (i.e., by the use stable epithelial cell lines and inducible effector expression), and identified a total of 130 putative EH-PPIs (including 63 EH-PPIs for PipB2 and 13 EH-PPIs for SifA) [ 52 ]. The observation that SifA and PipB2 localizations are steered by specific protein targeting mechanisms such as prenylation [ 53 ] and lipid raft-recruitment [ 54 ], respectively might (partially) account for the success of identifying EH-PPIs of these effectors in a cellular context.…”