Frank LAFONT

LAFONT Frank Group Leader (since sep 2005) : Cellular Microbiology and Physics of Infection Center of Infection and Immunity of Lille, CNRS, Institut Pasteur, INSERM, University Regional Hospital Center Lille, Univ of Lille   Formation and positions Cursus : Medical, Biology and Business Education. F Lafont graduated from the University Paris VI Pierre et Marie Curie and En savoir plus surFrank LAFONT[…]

Publié dans CV

Charge Blinking Statistics of Semiconductor Nanocrystals Revealed by Carbon Nanotube Single Charge Sensors

Nano Lett.201515 (10), pp 6349–6356

We demonstrate the relation between the optical blinking of colloidal semiconductor nanocrystals (NCs) and their electrical charge blinking for which we provide the first experimental observation of power-law statistics. To show this, we harness the performance of CdSe/ZnS NCs coupled with carbon nanotube field-effect transistors (CNTFETs), which act as single charge-sensitive electrometers with submillisecond time resolution, at room temperature. A random telegraph signal (RTS) associated with the NC single-trap […]

Interplay between troponin T phosphorylation and O-N-acetylglucosaminylation in ischaemic heart failure

Cardiovasc Res. 2015 Jul 1;107(1):56-65

Previous studies have reported that decreased serine 208 phosphorylation of troponin T (TnTpSer208) is associated with ischaemic heart failure (HF), but the molecular mechanisms and functional consequences of these changes are unknown. The aim of this study was to characterize the balance between serine phosphorylation and ON-acetylglucosaminylation (O-GlcNAcylation) of TnT in HF, its mechanisms, and the consequences of modulating these post-translational modifications.

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Quantifying bacterial adhesion on antifouling polymer brushes via single-cell force spectroscopy

Polym. Chem., 2015,6, 5740-5751

Bacterial adhesion poses serious problems in food safety and biomedical applications. Antifouling polymer brushes have been shown to be effective as surface modifications to prevent biofilm formation from pathogenic bacteria. In this work, the adhesion of Yersinia pseudotuberculosis on seven types of brushes is examined by single-cell force spectroscopy. The brushes, known to possess excellent resistance to protein adsorption, […]

Structured illumination microscopy and correlative microscopy to study autophagy

Autophagy Volume 75, 15 March 2015, Pages 61–68

Autophagy is a predominant eukaryotic mechanism for the engulfment of “portions” of cytoplasm allowing their degradation to recycle metabolites. The autophagy is ubiquitous among the life kingdom revealing the importance of this pathway that appears more complex than previously thought. Several reviews have already addressed how to monitor this pathway and have highlighted the existence of new routes such as the LC3-associated phagocytosis (LAP) and the non-canonical autophagy. The principal difference between autophagosomes and LAP vacuoles is that the former has two limiting membranes positives for LC3 whereas the latter has one.  […]

Autophagy in osteoblasts is involved in mineralization and bone homeostasis

Autophagy Volume 10, Issue 11, Aug 2014 pages 1965-1977

Bone remodeling is a tightly controlled mechanism in which osteoblasts (OB), the cells responsible for bone formation, osteoclasts (OC), the cells specialized for bone resorption, and osteocytes, the multifunctional mechanosensing cells embedded in the bone matrix, are the main actors. Increased oxidative stress in OB, the cells producing and mineralizing bone matrix, has been associated with osteoporosis development but the role of autophagy in OB has not yet been addressed. This is the goal of the present study. We first show that the autophagic process is induced in OB during mineralization. Then, using knockdown of autophagy-essential genes and OB-specific autophagy-deficient mice, we demonstrate that autophagy deficiency reduces mineralization capacity. Moreover, our data suggest that autophagic vacuoles could be used as vehicles in OB to secrete apatite crystals.  […]

Autophagy cover image

Autophagy, sept 2014, pp. 1588–1602. Yersinia pseudotuberculosis is contained within single-membrane, non-acidic, LC3-positive vacuoles in HeLa cells as observed using correlative light-electron microscopy (CLEM). The upper panel shows the confocal light scanning microscopy (CLSM) image of one infected cell labeled with DAPI (blue) and stably expressing mRFP-GFP-LC3. The lower panel shows the corresponding transmission electron microscopy (TEM) En savoir plus surAutophagy cover image[…]

Role of VAMP3 and VAMP7 in the commitment of Yersinia pseudotuberculosis to LC3-associated pathways involving single- or double-membrane vacuoles

Autophagy Volume 10, Issue 9, 2014, pages 1588-1602

Yersinia pseudotuberculosis can replicate inside macrophages by hijacking autophagy and blocking autophagosome acidification. In bone marrow-derived macrophages, the bacteria are mainly observed inside double-membrane vacuoles positive for LC3, a hallmark of autophagy. Here, we address the question of the membrane traffic during internalization of Yersinia investigating the role of vesicle- associated membrane proteins (VAMPs). First, we show that as in epithelial cells, Yersinia pseudotuberculosis replicates mainly in nonacidic LC3-positive vacuoles. Second, in these cells, we unexpectedly found that VAMP3 localizes preferentially to Yersinia-containing vacuoles (YCVs) with single […]

Pathogenic Neisseria meningitidis utilizes CD147 for vascular colonization

Nature Medicine 20, 725–731 

Neisseria meningitidis is a cause of meningitis epidemics worldwide and of rapidly progressing fatal septic shock. A crucial step in the pathogenesis of invasive meningococcal infections is the adhesion of bloodborne meningococci to both peripheral and brain endothelia, leading to major vascular dysfunction. Initial adhesion of pathogenic strains to endothelial cells relies on meningococcal type IV pili, but the endothelial receptor for bacterial adhesion remains unknown. Here, we report that the immunoglobulin superfamily member CD147 (also called extracellular matrix metalloproteinase inducer (EMMPRIN) or Basigin) is a critical host receptor for the meningococcal pilus components PilE and PilV […]

Cellular Dewetting : Opening of Macroapertures in Endothelial Cells

Phys. Rev. Lett. 108, 218105 – May 2012

Pathogenic bacteria can cross from blood vessels to host tissues by opening transendothelial cell macroapertures (TEMs). To induce TEM opening, bacteria intoxicate endothelial cells with proteins that disrupt the contractile cytoskeletal network. Cell membrane tension is no longer resisted by contractile fibers, leading to the opening of TEMs. Here we model the opening of TEMs as a new form of dewetting. While liquid dewetting is irreversible, we show that cellular dewetting is transient. Our model predicts the minimum radius […]