EspH utilizes phosphoinositide and Rab binding domains to interact with plasma membrane infection sites and Rab GTPases.

Enteropathogenic (EPEC) is a Gram-negative bacterial pathogen that causes persistent diarrhea. Upon attachment to the apical plasma membrane of the intestinal epithelium, the pathogen translocates virulence proteins called effectors into the infected cells. These effectors hijack numerous host processes for the pathogen's benefit.

Enteropathogenic infection co-elicits lysosomal exocytosis and lytic host cell death.

Enteropathogenic (EPEC) infection is a significant cause of gastroenteritis, mainly in children. Therefore, studying the mechanisms of EPEC infection is an important research theme. EPEC modulates its host cell life by injecting via a type III secretion machinery cell death modulating effector proteins.

Mitogen-Activated Protein Kinases (MAPKs) and Enteric Bacterial Pathogens: A Complex Interplay.

Diverse extracellular and intracellular cues activate mammalian mitogen-activated protein kinases (MAPKs). Canonically, the activation starts at cell surface receptors and continues via intracellular MAPK components, acting in the host cell nucleus as activators of transcriptional programs to regulate various cellular activities, including proinflammatory responses against bacterial pathogens. For instance, binding host pattern recognition receptors (PRRs) on the surface of intestinal epithelial cells to bacterial pathogen external components trigger the MAPK/NF-κB signaling cascade, eliciting cytokine production.

Topology and function of translocated EspZ.

EspZ and Tir are essential virulence effectors of enteropathogenic (EPEC). EspZ, the second translocated effector, has been suggested to antagonize host cell death induced by the first translocated effector, Tir (translocated intimin receptor). Another characteristic of EspZ is its localization to host mitochondria.

EspH interacts with the host active Bcr related (ABR) protein to suppress RhoGTPases.

Enteropathogenic are bacterial pathogens that colonize the gut and cause severe diarrhea in humans. Upon intimate attachment to the intestinal epithelium, these pathogens translocate via a type III secretion system virulent proteins, termed effectors, into the host cells. These effectors manipulate diverse host cell organelles and functions for the pathogen's benefit.

Type III secreted effectors that target mitochondria.

A type III secretion system (T3SS) is used by Gram-negative bacterial pathogens to secrete and translocate a battery of proteins, termed effectors, from the bacteria directly into the host cells. These effectors, which are thought to play a key role in bacterial virulence, hijack and modify the activity of diverse host cell organelles, including mitochondria. Mitochondria-the energy powerhouse of the cell-are important cell organelles that play role in numerous critical cellular processes, including the initiation of apoptosis and the induction of innate immunity.

Mitochondrial Targeting of the Enteropathogenic Escherichia coli Map Triggers Calcium Mobilization, ADAM10-MAP Kinase Signaling, and Host Cell Apoptosis.

The ability of diarrheagenic bacterial pathogens, such as enteropathogenic (EPEC), to modulate the activity of mitogen-activated protein kinases (MAPKs) and cell survival has been suggested to benefit bacterial colonization and infection. However, our understanding of the mechanisms by which EPEC modulate these functions is incomplete. In this study, we show that the EPEC type III secreted effector Map stimulates the sheddase activity of the disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) and the ERK and p38 MAPK signaling cascades.

Enteropathogenic Escherichia coli remodels host endosomes to promote endocytic turnover and breakdown of surface polarity.

Enteropathogenic E. coli (EPEC) is an extracellular diarrheagenic human pathogen which infects the apical plasma membrane of the small intestinal enterocytes. EPEC utilizes a type III secretion system to translocate bacterial effector proteins into its epithelial hosts.

Live cell near-field optical imaging and voltage sensing with ultrasensitive force control.

Force controlled optical imaging of membranes of living cells is demonstrated. Such imaging has been extended to image membrane potential changes to demonstrate that live cell imaging has been achieved. To accomplish this advance, limitations inherent in atomic force microscopy (AFM) since its inception in 1986 [G.

Live imaging of GLUT2 glucose-dependent trafficking and its inhibition in polarized epithelial cysts.

GLUT2 is a facilitative glucose transporter, expressed in polarized epithelial cells of the liver, intestine, kidney and pancreas, where it plays a critical role in glucose homeostasis. Together with SGLT1/2, it mediates glucose absorption in metabolic epithelial tissues, where it can be translocated apically upon high glucose exposure. To track the subcellular localization and dynamics of GLUT2, we created an mCherry-hGLUT2 fusion protein and expressed it in multicellular kidney cysts, a major site of glucose reabsorption.

Real-time sensing of enteropathogenic E. coli-induced effects on epithelial host cell height, cell-substrate interactions, and endocytic processes by infrared surface plasmon spectroscopy.

Enteropathogenic Escherichia coli (EPEC) is an important, generally non-invasive, bacterial pathogen that causes diarrhea in humans. The microbe infects mainly the enterocytes of the small intestine. Here we have applied our newly developed infrared surface plasmon resonance (IR-SPR) spectroscopy approach to study how EPEC infection affects epithelial host cells.

Surface plasmon-based infrared spectroscopy for cell biosensing.

Cell morphology is often used as a valuable indicator of the physical condition and general status of living cells. We demonstrate a noninvasive method for morphological characterization of adherent cells. We measure infrared reflectivity spectrum at oblique angle from living cells cultured on thin Au film, and utilize the unique properties of the confined infrared waves (i.

Real-time sensing of cell morphology by infrared waveguide spectroscopy.

We demonstrate that a live epithelial cell monolayer can act as a planar waveguide. Our infrared reflectivity measurements show that highly differentiated simple epithelial cells, which maintain tight intercellular connectivity, support efficient waveguiding of the infrared light in the spectral region of 1.4-2.

Retraction of enteropathogenic E. coli type IV pili promotes efficient host cell colonization, effector translocation and tight junction disruption.

Type IV pili (Tfp) play a primary role in mediating the adherence of pathogenic bacteria to their hosts. The pilus filament can retract with an immense force. However, the role of this activity in microbial pathogenesis has not been rigorously explored.

Bundle-forming pilus retraction enhances enteropathogenic Escherichia coli infectivity.

Enteropathogenic Escherichia coli (EPEC) is an important human pathogen that causes acute infantile diarrhea. The type IV bundle-forming pili (BFP) of typical EPEC strains are dynamic fibrillar organelles that can extend out and retract into the bacterium. The bfpF gene encodes for BfpF, a protein that promotes pili retraction.

Real-time monitoring of epithelial cell-cell and cell-substrate interactions by infrared surface plasmon spectroscopy.

The development of novel technologies capable of monitoring the dynamics of cell-cell and cell-substrate interactions in real time and a label-free manner is vital for gaining deeper insights into these most fundamental cellular processes. However, the label-free technologies available today provide only limited information on these processes. Here, we report a new (to our knowledge) infrared surface plasmon resonance (SPR)-based methodology that can resolve distinct phases of cell-cell and cell-substrate adhesion of polarized Madin Darby canine kidney epithelial cells.

Role for ADP ribosylation factor 1 in the regulation of hepatitis C virus replication.

We hypothesized that ADP-ribosylation factor 1 (Arf1) plays an important role in the biogenesis and maintenance of infectious hepatitis C virus (HCV). Huh7.5 cells, in which HCV replicates and produces infectious viral particles, were exposed to brefeldin A or golgicide A, pharmacological inhibitors of Arf1 activation.

EspM inhibits pedestal formation by enterohaemorrhagic Escherichia coli and enteropathogenic E. coli and disrupts the architecture of a polarized epithelial monolayer.

Enterohaemorrhagic Escherichia coli and enteropathogenic E. coli are enteropathogens characterized by their ability to induce the host cell to form actin-rich structures, termed pedestals. A type III secretion system, through which the pathogens deliver effector proteins into infected host cells, is essential for their virulence and pedestal formation.

Real-time monitoring of transferrin-induced endocytic vesicle formation by mid-infrared surface plasmon resonance.

We report on the application of surface plasmon resonance (SPR), based on Fourier transform infrared spectroscopy in the mid-infrared wavelength range, for real-time and label-free sensing of transferrin-induced endocytic processes in human melanoma cells. The evanescent field of the mid-infrared surface plasmon penetrates deep into the cell, allowing highly sensitive SPR measurements of dynamic processes occurring at significant cellular depths. We monitored in real-time, infrared reflectivity spectra in the SPR regime from living cells exposed to human transferrin (Tfn).

Enteropathogenic Escherichia coli subverts phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate upon epithelial cell infection.

Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)] and phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P(3)] are phosphoinositides (PIs) present in small amounts in the inner leaflet of the plasma membrane (PM) lipid bilayer of host target cells. They are thought to modulate the activity of proteins involved in enteropathogenic Escherichia coli (EPEC) infection. However, the role of PI(4,5)P(2) and PI(3,4,5)P(3) in EPEC pathogenesis remains obscure.

A Rab-GAP TBC domain protein binds hepatitis C virus NS5A and mediates viral replication.

Hepatitis C virus (HCV) is an important cause of liver disease worldwide. Current therapies are inadequate for most patients. Using a two-hybrid screen, we isolated a novel cellular binding partner interacting with the N terminus of HCV nonstructural protein NS5A.

Cholesterol-sensitive modulation of transcytosis.

Cholesterol-rich membrane domains (e.g., lipid rafts) are thought to act as molecular sorting machines, capable of coordinating the organization of signal transduction pathways within limited regions of the plasma membrane and organelles.

Infrared surface plasmon resonance: a novel tool for real time sensing of variations in living cells.

We developed a novel surface plasmon resonance (SPR) method, based on Fourier transform infrared (FTIR) spectroscopy, as a label-free technique for studying dynamic processes occurring within living cells in real time. With this method, the long (micrometer) infrared wavelength produced by the FTIR generates an evanescent wave that penetrates deep into the sample. In this way, it enables increased depth of sensing changes, covering significant portions of the cell-height volumes.