Abstract Mast cells upon stimulation through high affinity IgE receptors massively release inflammatory mediators by the fusion of specialized secretory granules (related to lysosomes) with plasma membrane. Using RBL-2H3 rat mast cell line, we investigated whether granule secretion involves components soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) machinery. Several isoforms each family SNARE proteins were expressed. Among those, synaptosome-associated 23 kDa...

Many intracellular pathogens rely on host cell membrane compartments for their survival. The strategies they have developed to subvert trafficking are often unknown, and SNARE proteins, which essential fusion, possible targets. obligate bacteria Chlamydia replicate within an vacuole, termed inclusion. A large family of bacterial proteins is inserted in the inclusion membrane, role these mostly unknown. Here we identify SNARE-like motifs protein IncA, conserved among most species. We show...

Pathogens use diverse molecular machines to penetrate host cells and manipulate intracellular vesicular trafficking. Viruses employ glycoproteins, functionally structurally similar the SNARE proteins, induce eukaryotic membrane fusion. Intracellular pathogens, on other hand, need block fusion of their infectious phagosomes with various endocytic compartments escape from degradative pathway. The details concerning mechanisms underlying this process are lacking. Using both an in vitro liposome...

Aggregation of high affinity IgE receptors (Fc epsilonRI) expressed on mast cells and basophils is a potent stimulus for the release inflammatory mediators from cytoplasmic granules. Fc epsilonRI-dependent exocytosis requires activation protein kinase C mobilization calcium intra- extracellular stores. However, how these events ultimately regulate membrane fusion step between granules plasma still remains unclear. In this study, we investigated role small GTPases rab3 subfamily in regulated...

Soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins constitute the core of fusion machinery, and isolated SNAREs fuse membranes with exquisite specificity by cognate pairing. Most have a membrane-spanning region, an N-terminal domain, membrane proximal SNARE motif domain. Although is critical for complex formation, it sole determinant SNARE-dependent fusion? To test this, we make use functioning in late endosomal compartment yeast. Studying this previously...

ABSTRACT The intracellular bacterium Chlamydia trachomatis develops in a parasitic compartment called the inclusion. Posttranslationally modified microtubules encase inclusion, controlling positioning of Golgi complex fragments around molecular mechanisms by which coopts host cytoskeleton and to sustain its infectious are unknown. Here, using genetically strain, we discovered that both posttranslationally inclusion controlled chlamydial protein CT813/CTL0184/InaC ARF GTPases. CT813 recruits...

Chlamydia trachomatis is an obligate intracellular pathogen that the etiological agent of a variety human diseases, including blinding trachoma and sexually transmitted infections. Chlamydiae replicate within membrane-bound compartment, termed inclusion, which they extensively modify by insertion type III secreted proteins called Inc proteins. IncA inclusion membrane protein encodes two coiled-coil domains are homologous to eukaryotic SNARE (soluble N-ethylmaleimide-sensitive factor...

A new functional class of SNAREs, designated inhibitory SNAREs (i-SNAREs), is described here. An i-SNARE inhibits fusion by substituting for or binding to a subunit fusogenic SNAREpin form nonfusogenic complex. Golgi-localized were tested activity adding them as fifth SNARE together with four other that mediate Golgi reactions. striking pattern emerges in which certain subunits the cis-Golgi function i-SNAREs inhibit mediated trans-Golgi SNAREpin, and vice versa. Although opposing...

The t-SNARE in a late Golgi compartment (Tlg2p) syntaxin is required for endocytosis and localization of cycling proteins to the yeast. We show here that Tlg2p assembles with two light chains, Tlg1p Vti1p, form functional mediates fusion, specifically v-SNAREs Snc1p Snc2p. In vitro, this inert, locked nonfunctional state, unless it activated fusion. Activation can be mediated by peptide derived from v-SNARE, which likely bypasses additional regulatory cell. Locking t-SNAREs creates potential...

To penetrate host cells through their membranes, pathogens use a variety of molecular components in which the presence heptad repeat motifs seems to be prevailing element. Heptad repeats are characterized by pattern seven, generally hydrophobic, residues. In order initiate membrane fusion, viruses glycoproteins-containing repeats. These proteins structurally and functionally similar SNARE known involved eukaryotic fusion. SNAREs also display motif called "SNARE motif". As bacterial genomes...

Chlamydia trachomatis replicates in a parasitophorous membrane-bound compartment called an inclusion. The inclusions corrupt host vesicle trafficking networks to avoid the degradative endolysosomal pathway but promote fusion with each other order sustain higher bacterial loads process known as homotypic fusion. protein IncA (Inclusion A) appears play central roles both these processes it participates and inhibits endocytic SNARE-mediated membrane How selectively or activates remains poorly...

Chlamydia trachomatis is an obligate intracellular bacterium that has developed sophisticated mechanisms to survive inside its infectious compartment, the inclusion. Notably, weaves extensive network of microtubules (MTs) and actin filaments enable interactions with host organelles enhance stability. Despite global health economic burden caused by this sexually transmitted pathogen, little known about how MT scaffolds are integrated into increasingly complex virulence system. Previously, we...

Mast cells play a critical role in the innate immune response to bacterial infection. They internalize and kill variety of bacteria process antigen for presentation T via MHC molecules. Although mast cell phagocytosis appears significant during infection, little is known about proteins involved its regulation. In this study, we demonstrate that SNARE protein SNAP29 phagocytosis. localized endocytic pathway transiently recruited Escherichia coli (E. coli)-containing phagosomes. Interestingly,...

Abstract Many intracellular bacteria, including Chlamydia , establish a parasitic membrane-bound organelle inside the host cell that is essential for bacteria’s survival. trachomatis forms inclusions are decorated with poorly characterized membrane proteins known as Incs. The prototypical Inc, called IncA, enhances pathogenicity by promoting homotypic fusion of and shares structural functional similarity to eukaryotic SNAREs. Here, we present atomic structure cytoplasmic domain which reveals...

Mast cells orchestrate the allergic response through release of proinflammatory mediators, which is driven by fusion cytoplasmic secretory granules with plasma membrane. During this process, SNARE proteins including Syntaxin4, SNAP23 and VAMP8 play a key role. Following stimulation, kinase IKKβ interacts phosphorylates t-SNARE SNAP23. Phosphorylated then associates Syntaxin4 v-SNARE to form ternary complex, drives membrane mediator release. Interestingly, mast cell degranulation impaired...

Both actin and microtubules are major cytoskeletal elements in eukaryotic cells that participate many cellular processes, including cell division motility, vesicle organelle movement, the maintenance of shape. Inside its host cell, human pathogen Chlamydia trachomatis manipulates cytoskeleton to promote survival enhance pathogenicity. In particular, induces drastic rearrangement both microtubules, which is vital for entry, inclusion structure development, exit. As significant progress...

Chlamydia trachomatis is the leading cause of sexually transmitted bacterial disease and a global health burden. As an obligate intracellular pathogen, has evolved many strategies to manipulate its host establish niche called inclusion. C. reorganizes actin cytoskeleton form scaffolds around inclusion reinforce growing membrane. To control kinetics formation scaffolds, expresses effector InaC/CT813, which activates GTPase RhoA. Here, we have discovered that InaC stabilizes through...