Autophagy is a normal degradative pathway that involves the sequestration of cytoplasmic components and organelles in vacuole called an autophagosome finally fuses with lysosome. Rab7 member Rab family involved transport to late endosomes biogenesis perinuclear lysosome compartment. To assess role autophagy we stably transfected CHO cells wild-type pEGFP-Rab7, mutants T22N (GDP form) Q67L (GTP form). was induced by amino acid starvation autophagic vacuoles were labeled monodansylcadaverine....

Pathogens evolved mechanisms to invade host cells and multiply in the cytosol or compositionally functionally customized membrane-bound compartments. Coxiella burnetii, agent of Q fever man is a Gram-negative γ-proteobacterium which multiplies large, acidified, hydrolase-rich fusogenic vacuoles with phagolysosomal-like characteristics. We reported previously that C. burnetii phase II replicative compartments are labelled by LC3, protein specifically localized autophagic vesicles. show here...

The etiologic agent of Q fever Coxiella burnetii, is an intracellular obligate parasite that develops large vacuoles with phagolysosomal characteristics, containing multiple replicating bacteria. We have previously shown Phase II C. burnetii replicative generated after 24-48 h post infection are decorated the autophagic protein LC3. aim present study was to examine, at earlier stages infection, distribution and roles small GTPases Rab5 Rab7, markers early late endosomes respectively, as well...

The obligate intracellular bacterium Coxiella burnetii, the agent of Q fever in humans and coxiellosis other animals, survives replicates within large, acidified, phagolysosome-like vacuoles known to fuse homo- heterotypically with vesicles. To further characterize these vacuoles, HeLa cells were infected C. burnetii phase II; 48 h later, bacteria-containing labeled by LysoTracker, a marker acidic compartments, accumulated monodansylcadaverine displayed protein LC3, both markers autophagic...

Autophagy is a process by which cytoplasmic material sequestered in double-membrane vesicle destined for degradation. Nutrient deprivation stimulates the pathway and number of autophagosomes cell increases response to such stimulus. In current report we have demonstrated that actin necessary starvation-mediated autophagy. When cytoskeleton depolymerized, increase autophagic vacuoles starvation stimulus was abolished without affecting maturation remaining autophagosomes. addition, filaments...

Survival or destruction of a pathogen following phagocytosis depends, in part, on fusion events between the phagosome and endosomal lysosomal compartments. Here we use an vitro assay to show that phagosome-endosome is regulated by small GTPase rab5 are influenced internalized live organism, Listeria monocytogenes (LM). We compare phagosomes containing heat-killed organisms (dead LM) with nonhemolytic mutant (live LMhly-). Unlike wild-type LMhly- remains trapped inside phagosome....

Calmodulin (CaM) has previously been implicated in regulated exocytosis, transcytosis, and receptor recycling. We have investigated the role of CaM endocytic transport by examining effects several antagonists intact cells. present evidence indicating that mixing sequentially internalized ligands is inhibited antagonists, may play a general regulating endosomal membrane trafficking. To address specific events are affected we studied its an vitro assay reconstitutes fusion among endosomes....

Fusion among endosomes is an important step for transport and sorting of internalized macromolecules. Working in a cell-free system, we have previously reported that, the absence externally added calcium, endosome fusion requires cytosol, ATP, sensitive to N-ethylmaleimide (NEM) anti-NEM-sensitive factor (NSF) antibody. This cytosol-dependent regulated by monomeric heterotrimeric GTP-binding proteins. Further studies revealed, however, that presence micromolar concentrations free observed...

We have reconstituted fusion between phagosomes and lysosomes in streptolysin <i>O</i>-permeabilized J774-E macrophages. Fusion was assessed by measuring the delivery of avidin-conjugated horseradish peroxidase pre-internalized into to containing biotinylated β-glucuronidase-conjugated paramagnetic beads (1–2 μm). dependent on energy exogenously supplied cytosol. Phagosome-lysosome greatly inhibited when microtubules were depolymerized nocodazole treatment, suggesting that occurs via...

Trimeric G proteins have emerged as important regulators of membrane trafficking. To explore a role for Gβγ in endosome fusion, we taken advantage β-adrenergic receptor kinase (βARK), an enzyme translocated to membranes by interaction with Gβγ. The COOH terminus βARK (βARKct) has Gβγ-binding domain which blocks some Gβγ-mediated processes. We found that βARKct and peptide G, derived from βARKct, inhibit vitro fusion. Interestingly, ARF share sequence similarity. Peptide reversed ARF-mediated...

Q fever is a disease caused by Coxiella burnetii. In the host cell, this pathogen generates large parasitophorous vacuole (PV) with lysosomal characteristics. Here we show that F-actin not only recruited to but also involved in formation of typical PV. Treatment infected cells F-actin-depolymerizing agents alters PV development. The small PVs formed latrunculin B-treated were loaded transferrin and Lysotracker labeled an antibody against cathepsin D, suggesting B did affect cargo its...

Rab24 is an atypical member of the Rab GTPase family whose distribution in interphase cells has been characterized; however, its function remains largely unknown. In this study, we have analyzed throughout cell division. We observed that was located at mitotic spindle metaphase, midbody during telophase and furrow cytokinesis. also partial co-localization tubulin demonstrated association to microtubules. Interestingly, more than 90% transiently transfected HeLa with presented abnormal...

The genomic actions of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) are mediated by the intracellular vitamin D receptor (VDR). Although immunocytochemistry has shown that disruption microtubular assembly prevents nuclear access sterol-VDR complex, role microtubules in response to 1,25(OH)2D3 not been studied viable cells. Our studies examined this interaction normal human monocytes. Monocytes convert 25(OH)D3 and 24-hydroxylated metabolites more polar than 1,25(OH)2D3. Microtubule totally...

The GTPases belonging to the Rho family control actin cytoskeleton rearrangements needed for particle internalization during phagocytosis. ROCK and mDia1 are downstream effectors of RhoA, a GTPase involved in that process. Coxiella burnetii, etiologic agent Q fever, is internalized by host´s cells an actin-dependent manner. Nevertheless, molecular mechanism this process has been poorly characterized. This work analyzes role different some C. burnetii phagocytic non-phagocytic cells. into...

Background Cortactin is a key regulator of the actin cytoskeleton and involved in pathogen-host cell interactions. Numerous pathogens exploit phagocytic process to infect host cells. Coxiella burnetii, etiologic agent Q fever, internalized by cells through molecular mechanism that poorly understood. Methodology/Principal Finding Here we analyzed role different cortactin motifs internalization C. burnetii non-phagocytic into HeLa was significantly reduced when expressed GFP-cortactin W525K,...

Dendritic cells (DCs) play critical functions in the initiation of immune responses. Understanding their role reactive arthritis (ReA) will help delineate pathogenesis this arthropathy. In early studies, we detected IL-12/23p40 deregulation Yersinia entercolitica (Ye)-induced ReA TNFRp55-deficient (TNFRp55-/-) mice. study, assessed contribution DCs overproduction. First, greater levels IL-12/23p40, IFN-γand IL-17A were confirmed supernatants lipopolysaccharide (LPS)-stimulated...

Particle internalization in macrophages is followed by a complex maturation process. We have previously observed that proteins bound to phagocytosed particles are sorted from phagosomes into heterogeneous population of vesicles fuse with endosomes. However, the mechanism and protein machinery involved formation these phagosome-derived largely unknown. It has been shown coated coat type I (COPI) role both secretion endocytosis. To address possibility COPI might participate we studied...

No AccessJournal of UrologyInvestigative Urology1 Feb 1999RECOVERY OF DISTAL NEPHRON ENZYME ACTIVITY AFTER RELEASE UNILATERAL URETERAL OBSTRUCTION P. VALLES, V. MERLO, W. BERON, and MANUCHA VALLESP. VALLES More articles by this author , MERLOV. MERLO BERONW. BERON MANUCHAW. View All Author Informationhttps://doi.org/10.1016/S0022-5347(01)61987-6AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract Purpose:...

Ezrin protein is involved in the interaction of actin cytoskeleton with membrane receptors such as CD44. It regulates plasma dynamics and intracellular signaling. Coxiella burnetii, etiologic agent Q fever, internalized into host cell through a poorly characterized molecular mechanism. Here we analyzed role ezrin CD44 C. burnetii internalization by HeLa cells. The knockdown inhibited bacterial uptake. Interestingly, at early stages internalization, was recruited to fraction phosphorylated....

Particle internalization in macrophages is followed by a complex maturation process. We have previously observed that proteins bound to phagocytosed particles are sorted from phagosomes into heterogeneous population of vesicles fuse with endosomes. However, the mechanism and protein machinery involved formation these phagosome-derived largely unknown. It has been shown coated coat type I (COPI) role both secretion endocytosis. To address possibility COPI might participate we studied...

Microtubules (Mts) are dynamic cytoskeleton structures that play a key role in vesicular transport. The Mts-mediated transport depends on motor proteins named kinesins and the dynein/dynactin complex. Rab7 adapter protein FYCO1 controls anterograde of endocytic compartments through interaction with kinesin KIF5. its partner RILP induce recruitment to late endosomes regulating retrograde perinuclear area fuse lysosomes. endosomal-lysosomal fusion is regulated by HOPS complex GTPase Arl8....

It is now well established that GTP-binding proteins are important regulators of vesicular transport. Recent work has shown multiple GTPases (both monomeric and heterotrimeric) required for trafficking. In the present study we have used aluminum fluoride (AIF), a reagent activates trimeric G proteins, as tool to involvement this family in regulation endocytosis intact cells. Our results indicate AIF inhibits fusion early endosomes with an intracellular proteolytic compartment. Using mixing...