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Visualizing the dynamics of exported bacterial proteins with the chemogenetic fluorescent reporter FAST.
Chekli, Yankel; Peron-Cane, Caroline; Dell'Arciprete, Dario; Allemand, Jean-François; Li, Chenge; Ghigo, Jean-Marc; Gautier, Arnaud; Lebreton, Alice; Desprat, Nicolas; Beloin, Christophe
journal article - 10(1) 15791 - 10.1038/s41598-020-72498-2 - 2020
Bacterial proteins exported to the cell surface play key cellular functions. However, despite the interest to study the localisation of surface proteins such as adhesins, transporters or hydrolases, monitoring their dynamics in live imaging remains challenging, due to the limited availability of fluorescent probes remaining functional after secretion. In this work, we used the Escherichia coli intimin and the Listeria monocytogenes InlB invasin as surface exposed scaffolds fused with the recently developed chemogenetic fluorescent reporter protein FAST. Using both membrane permeant (HBR-3,5DM) and non-permeant (HBRAA-3E) fluorogens that fluoresce upon binding to FAST, we demonstrated that fully functional FAST can be exposed at the cell surface and used to specifically tag the external side of the bacterial envelop in both diderm and monoderm bacteria. Our work opens new avenues to study the organization and dynamics of the bacterial cell surface proteins.
Fluorescent secreted bacterial effectors reveal active intravacuolar proliferation of Listeria monocytogenes in epithelial cells.
Peron-Cane, Caroline; Fernandez, José-Carlos; Leblanc, Julien; Wingertsmann, Laure; Gautier, Arnaud; Desprat, Nicolas; Lebreton, Alice
journal article - 16(10) e1009001 - 10.1371/journal.ppat.1009001 - 2020
Real-time imaging of bacterial virulence factor dynamics is hampered by the limited number of fluorescent tools suitable for tagging secreted effectors. Here, we demonstrated that the fluorogenic reporter FAST could be used to tag secreted proteins, and we implemented it to monitor infection dynamics in epithelial cells exposed to the human pathogen Listeria monocytogenes (Lm). By tracking individual FAST-labelled vacuoles after Lm internalisation into cells, we unveiled the heterogeneity of residence time inside entry vacuoles. Although half of the bacterial population escaped within 13 minutes after entry, 12% of bacteria remained entrapped over an hour inside long term vacuoles, and sometimes much longer, regardless of the secretion of the pore-forming toxin listeriolysin O (LLO). We imaged LLO-FAST in these long-term vacuoles, and showed that LLO enabled Lm to proliferate inside these compartments, reminiscent of what had been previously observed for Spacious Listeria-containing phagosomes (SLAPs). Unexpectedly, inside epithelial SLAP-like vacuoles (eSLAPs), Lm proliferated as fast as in the host cytosol. eSLAPs thus constitute an alternative replication niche in epithelial cells that might promote the colonization of host tissues.s.
Fluorescence-free quantification of protein/nucleic-acid binding through single-molecule kinetic locking
Martin Rieu; Valle-Orero, Jessica; Ducos, Bertrand; Allemand, Jean-François; Croquette, Vincent
bioRxiv - - 10.1101/2020.09.30.321232 - 2020
Fluorescence-free micro-manipulation of nucleic acids (NA) allows the functional characterization of DNA/RNA processing proteins, without the interference of labels, but currently fails to detect and quantify their binding. To overcome this limitation, we developed a new method based on single-molecule force spectroscopy, called kinetic locking, that allows a direct in vitro visualization of protein binding while avoiding any kind of chemical disturbance of the protein’s natural function. We validate kinetic locking by measuring accurately the hybridization energy of ultrashort nucleotides (5,6,7 bases) and use it to measure the dynamical interactions of E. coli RecQ helicase with its DNA substrate.Competing Interest StatementThe authors have declared no competing interest.
Performance evaluation of a MIP for the MISPE-LC determination of p-[18F]MPPF and a potential metabolite in human plasma
F.Lecomte J.Aerts Plenevaux .Defraiteur. Chapuis-Hugonc. Rozetd. Chiape. Luxen. Pichon, Ph.Huberta C.Huberta
ELSEVIER - 180 113015 - https://doi.org/10.1016/j.jpba.2019.113015 - 2020
The mapping of post-translational modifications (PTMs) of proteins can be addressed by bottom-up proteomics strategy using proteases to achieve the enzymatic digestion of the biomolecule. Glycosylation is one of the most challenging PTM to characterize due to its large structural heterogeneity. In this work, two Immobilized Enzyme Reactors (IMERs) based on trypsin and pepsin protease were used for the first time to fasten and improve the reliability of the specific mapping of the N-glycosylation heterogeneity of glycoproteins. The performance of the supports was evaluated with the digestion of human Chorionic Gonadotropin hormone (hCG), a glycoprotein characterized by four N- and four O-glycosylation sites, prior to the analysis of the digests by nanoliquid chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS). Firstly, the repeatability of the nanoLC-MS/MS was evaluated and a method to control the identification of the identified glycans was developed to validate them regarding the retention time of glycopeptides in reversed phase nanoLC separation. The repeatability of the digestion with trypsin-based IMER was evaluated on the same hCG batch and on three independent batches with common located glycans up to 75%. Then, the performance of the IMER digestions was compared to in-solution digestions to evaluate the qualitative mapping of the glycosylation. It has given rise to 42 out of 45 common glycans between both digestions modes. For the first time, the complementarity of trypsin and pepsin was illustrated for the glycosylation mapping as trypsin led to identifications on 2 out of 4 glycosylation site while pepsin was informative on the 4 glycosylation site. The potential of IMERs for the study of the glycosylation of a protein was illustrated with the comparison of two hCG-based drugs, Ovitrelle® and Pregnyl
Identification and semi-relative quantification of intact glycoforms by nano-LC–(Orbitrap)MS: application to the α-subunit of human chorionic gonadotropin and follicle-stimulating hormone
Amira Al Matari, Audrey Combès, Julien Camperi, Thierry Fournier, Valérie Pichon & Nathalie Delaunay
ELSEVIER - 412 5729–5741 - , 10.1007/s00216-020-02794-3 - 2020
Human chorionic gonadotropin (hCG) and follicle-stimulating hormone (FSH) belong to the family of glycoprotein polypeptide hormones called gonadotropins. They are heterodimers sharing the α-subunit structure that has 2 N-glycosylation sites. A method based on nano-reversed-phase liquid chromatography coupled to high-resolution mass spectrometry with an Orbitrap analyzer was developed for the first time to characterize the glycosylation state of the α-subunit at the intact level. A recombinant hCG-based drug, Ovitrelle®, was analyzed. This method combined with an appropriate data treatment allowed the detection of not only the major isoforms but also the minority ones with a high mass accuracy. More than 30 hCGα glycoforms were detected without overlapping of the isotopic patterns. The figures of merit of the method were assessed. The relative standard deviations (RSDs) of the retention time ranged between 0.1 and 6.08% (n = 3), with an average of 0.4%. The RSDs of the peak area measured on the extracted ion chromatogram of each glycoform are below 38% (n = 3), with an average of 16%, thus allowing semi-relative quantification. The ability to accurately profile glycosylated variants of hCGα was next demonstrated by comparing qualitatively and semi-quantitatively 3 batches of Ovitrelle®. The method was also used to analyze 3 batches of a recombinant FSH-based drug, Puregon®, and 30 FSHα glycoforms were detected and semi-quantified. This demonstrates the high potential of this method for fast quality control or comparison of the glycosylation of glycoprotein-based pharmaceutical preparations.
Identification and semi-relative quantification of intact glycoforms by nano-LC–(Orbitrap)MS: application to the α-subunit of human chorionic gonadotropin and follicle-stimulating hormone
Julien Camperi, Audrey Combès, Thierry Fournier, Valerie Pichon & Nathalie Delaunay
Research Paper - 412 4423–4432 - 10.1007/s00216-020-02684-8 - 2020
In the present work, the human chorionic gonadotropin (hCG) hormone was characterized for the first time by hydrophilic interaction liquid chromatography (HILIC) coupled to high-resolution (HR) quadrupole/time-of-flight (qTOF) mass spectrometry (MS) at the intact level. This heterodimeric protein, consisting of two subunits (hCGα and hCGβ), possesses 8 potential glycosylation sites leading to a high number of glycoforms and has a molecular weight of about 35 kDa. The HILIC conditions optimized in a first paper but using UV detection were applied here with MS for the analysis of two hCG-based drugs, a recombinant hCG and a hCG isolated from the urine of pregnant women. An amide column (150 × 2.1 mm, 2.6 μm, 150 Å), a mobile phase composed of acetonitrile and water both containing 0.1% of trifluoroacetic acid, and a temperature of 60 °C were used. The gradient was from 85 to 40% ACN in 30 min. The use of TFA that had been shown to be necessary for the separation of glycoforms caused, as expected, an ion suppression effect in MS that was partially overcome by increasing the amount of protein injected (2 μL at 1 mg mL−1) and reducing the detection m/z range (from 1500 to 300). These conditions allowed the detection of different glycoforms of hCGα. The performance of the HILIC-HRMS method was compared with that previously obtained in RPLC-HRMS in terms of the number of detected glycoforms, selectivity, and sensitivity. The complementarity and orthogonality of the HILIC and RP modes for the analysis of hCG at the intact level were demonstrated.
Development of Immobilized Enzyme Reactors for the characterization of the glycosylation heterogeneity of a protein
Stan Perchepied, Nicolas Eskenazi, Chiara Giangrande, Julien Camperi, Thierry Fournier, Joëlle Vinh, Nathalie Delaunay, Valérie Pichon
ELSEVIER - 209 120568 - doi.org/10.1016/j.talanta.2019.120171 - 2020
The mapping of post-translational modifications (PTMs) of proteins can be addressed by bottom-up proteomics strategy using proteases to achieve the enzymatic digestion of the biomolecule. Glycosylation is one of the most challenging PTM to characterize due to its large structural heterogeneity. In this work, two Immobilized Enzyme Reactors (IMERs) based on trypsin and pepsin protease were used for the first time to fasten and improve the reliability of the specific mapping of the N-glycosylation heterogeneity of glycoproteins. The performance of the supports was evaluated with the digestion of human Chorionic Gonadotropin hormone (hCG), a glycoprotein characterized by four N- and four O-glycosylation sites, prior to the analysis of the digests by nanoliquid chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS). Firstly, the repeatability of the nanoLC-MS/MS was evaluated and a method to control the identification of the identified glycans was developed to validate them regarding the retention time of glycopeptides in reversed phase nanoLC separation. The repeatability of the digestion with trypsin-based IMER was evaluated on the same hCG batch and on three independent batches with common located glycans up to 75%. Then, the performance of the IMER digestions was compared to in-solution digestions to evaluate the qualitative mapping of the glycosylation. It has given rise to 42 out of 45 common glycans between both digestions modes. For the first time, the complementarity of trypsin and pepsin was illustrated for the glycosylation mapping as trypsin led to identifications on 2 out of 4 glycosylation site while pepsin was informative on the 4 glycosylation site. The potential of IMERs for the study of the glycosylation of a protein was illustrated with the comparison of two hCG-based drugs, Ovitrelle® and Pregnyl
S-nitrosylation affects TRAP1 structure and ATPase activity and modulates cell response to apoptotic stimuli
Fiorella Faienza, Matteo Lambrughi, Salvatore Rizza, Chiara Pecorari, Paola Giglio, Juan Salamanca Viloria, Maria Francesca Allega, Giovanni Chiappetta, Joëlle Vinh, Francesca Pacello, Andrea Battistoni, Andrea Rasola, Elena Papaleo, Giuseppe Filomeni
bioRxiv - - doi: 10.1016/j.bcp.2020.113869 - 2020
The mitochondrial chaperone TRAP1 has been involved in several mitochondrial functions, and modulation of its expression/activity has been suggested to play a role in the metabolic reprogramming distinctive of cancer cells. TRAP1 posttranslational modifications, i.e. phosphorylation, can modify its capability to bind to different client proteins and modulate its oncogenic activity. Recently, it has been also demonstrated that TRAP1 is S-nitrosylated at Cys501, a redox modification associated with its degradation via the proteasome. Here we report molecular dynamics simulations of TRAP1, together with analysis of long-range structural communication, providing a model according to which Cys501 S-nitrosylation induces conformational changes to distal sites in the structure of the protein. The modification is also predicted to alter open and closing motions for the chaperone function. By means of colorimetric assays and site directed mutagenesis aimed at generating C501S variant, we also experimentally confirmed that selective S-nitrosylation of Cys501 decreases ATPase activity of recombinant TRAP1. Coherently, C501S mutant was more active and conferred protection to cell death induced by staurosporine. Overall, our results provide the first in silico, in vitro and cellular evidence of the relevance of Cys501 S-nitrosylation in TRAP1 biology.
The zoonotic pathogen Leptospira interrogans mitigates environmental stress through cyclic-di-GMP-controlled biofilm production
Thibeaux R, Soupé-Gilbert ME, Kainiu M, Girault D, Bierque E, Fernandes J, Bähre H, Douyère A, Eskenazi N, Vinh J, Picardeau M, Goarant C
NPJ Biofilms Microbiomes - 6(1) 24 - DOI [DOI] – 10.1038/s41522-020-0134-1 - 2020
The zoonotic bacterium Leptospira interrogans is the aetiological agent of leptospirosis, a re-emerging infectious disease that is a growing public health concern. Most human cases of leptospirosis result from environmental infection. Biofilm formation and its contribution to the persistence of virulent leptospires in the environment or in the host have scarcely been addressed. Here, we examined spatial and time-domain changes in biofilm production by L. interrogans. Our observations showed that biofilm formation in L. interrogans is a highly dynamic process and leads to a polarized architecture. We notably found that the biofilm matrix is composed of extracellular DNA, which enhances the biofilm’s cohesiveness. By studying L. interrogans mutants with defective diguanylate cyclase and phosphodiesterase genes, we show that biofilm production is regulated by intracellular levels of bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) and underpins the bacterium’s ability to withstand a wide variety of simulated environmental stresses. Our present results show how the c-di-GMP pathway regulates biofilm formation by L. interrogans, provide insights into the environmental persistence of L. interrogans and, more generally, highlight leptospirosis as an environment-borne threat to human health.
On-Chip Sample Preparation Using a ChipFilter Coupled to NanoLC-MS/MS for Bottom-Up Proteomics
Massamba M Ndiaye, Ha Phuong Ta, Giovanni Chiappetta, Joëlle Vinh
J Proteome Res - 19(7) 2654-2663 - DOI: 10.1021/acs.jproteome.9b00832 - 2020
Sample preparation is a crucial step in bottom-up proteomics. Analytical performances of bottom-up proteomics can be improved by the miniaturization of sample preparation. Many microfluidic devices have been designed in the field of proteomics, but many of them are not capable of handling complex samples and do not integrate the processing and digestion steps. We propose a ChipFilter Proteolysis (CFP) microfluidic device as a proteomics reactor for the miniaturization of protein sample processing and digestion steps, whose design is closely related to the experimental setup of filter-aided sample processing, even if no denaturing surfactant is required. The microchip has two reaction chambers of 0.6 μL volume separated by a protein filtration membrane in regenerated cellulose (10kD cutoff) that will concentrate or retain large polypeptides and will release small molecules. Cell lysis, protein concentration, and rapid chemical or enzymatic treatment can be performed in the ChipFilter. Complex proteomic samples like yeast protein extract or whole human cells proteome have been successfully analyzed with our microchip. Compared with the membrane-based commercial ultracentrifugation cartridge, our microfluidic device offered a better proteome coverage with 10 times less starting material and 8 times faster protocol duration.

578 publications.