Chlamydia Internalization and Intracellular Fate

Scidmore-Carlson, Marci A.; Hackstadt, Ted

doi:10.1007/978-1-4757-4580-1_18

Cited by 5 publications

(4 citation statements)

References 86 publications

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“…Parachlamydia acanthamoebae is the first member of the order Chlamydiales, which is shown to traffic in association with vacuoles of the endocytic pathway. This is of importance, as Chlamydiaceae appear to completely bypass the early endocytic pathway (Scidmore-Carlson and Hackstadt, 2000), and replicate within an inclusion that is trafficked to the peri-Golgi region where it fuses with exocytic vesicles (Hackstadt et al, 1995). Early synthesis of chlamydial proteins apparently regulate the traffic of the chlamydial inclusion (Scidmore et al, 1996), by recruiting some rab GTPases (rab1, rab4, rab11), which are key regulators of membrane trafficking.…”

Section: Discussionmentioning

confidence: 99%

“…escape the endocytic pathway and replicate in a vacuole in close contact with the trans ‐Golgi network (Hackstadt et al ., 1995; Wolf and Hackstadt, 2001). Nevertheless, as P. acanthamoebae diverged from Chlamydiaceae more than 700 millions years ago (Greub and Raoult, 2003), it may use another strategy to resist to human macrophages and, like Legionella , multiplie within endoplasmic reticulum‐associated vacuoles (Scidmore‐Carlson and Hackstadt, 2000; Roy and Tilney, 2002). It may, also like Mycobacterium sp., interfere with phagosome maturation and replicate within endocytic vacuoles that did not acquired the vacuolar proton ATPase (v‐ATPase) responsible for the acidic pH of lysosome (Sturgill‐Koszycki et al ., 1994) or, like Tropheryma whipplei , replicate within acidic phagosomes, lacking lysosomal hydrolases such as cathepsin D (Ghigo et al ., 2002).…”

Section: Introductionmentioning

confidence: 99%

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Intracellular trafficking of Parachlamydia acanthamoebae

Greub

Mège

Gorvel

et al. 2005

Cellular Microbiology

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SummaryParachlamydia acanthamoebae is an obligate intracellular bacterium that naturally infects free-living amoebae. It is a potential agent of pneumonia that resists destruction by human macrophages. However, the strategy used by this Chlamydia -like organism in order to resist to macrophage destruction is unknown. We analysed the intracellular trafficking of P. acanthamoebae within monocyte-derived macrophages. Infected cells were immunolabelled for the bacteria and for various intracellular compartments by using specific antibodies. We analysed the bacteria colocalization with the different subcellular compartments by using epifluorescence and confocal microscopy. Bacterial replication took place 4-6 h post infection within acidic vacuoles. At that time, P. acanthamoebae colocalized with Lamp-1, a membrane marker of late endosomal and lysosomal compartments. A transient accumulation of EEA1 15 min post infection, and of rab7 and the mannose 6-phosphate receptor 30 min post infection confirmed that P. acanthamoebae traffic through the endocytic pathway. The acquisition of Lamp-1 was not different after infection with living and heat-inactivated bacteria. However, 24.5% and 79.5% of living and heat-inactivated P. acanthamoebae , respectively, colocalized with the vacuolar proton ATPase. Moreover, P. acanthamoebae did not colocalized with cathepsin D, a lysosomal hydrolase, suggesting that P. acanthamoebae interferes with maturation of its vacuole. Thus, P. acanthamoebae survives to destruction by human macrophages probably by controlling the vacuole biogenesis.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intracellular trafficking of Parachlamydia acanthamoebae

Greub

Mège

Gorvel

et al. 2005

Cellular Microbiology

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“…Several chlamydial ligands and host receptors have been proposed, although there has been little consensus as to which of the number of chlamydial ligands and host receptors are of primary importance. It is likely that many of these ligand-receptor interactions function in infection of different cell and tissue types conferring an advantage during infection [5].…”

Section: Introductionmentioning

confidence: 99%

Chlamydial Entry Involves TARP Binding of Guanine Nucleotide Exchange Factors

et al. 2008

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Chlamydia trachomatis attachment to cells induces the secretion of the elementary body–associated protein TARP (Translocated Actin Recruiting Protein). TARP crosses the plasma membrane where it is immediately phosphorylated at tyrosine residues by unknown host kinases. The Rac GTPase is also activated, resulting in WAVE2 and Arp2/3-dependent recruitment of actin to the sites of chlamydia attachment. We show that TARP participates directly in chlamydial invasion activating the Rac-dependent signaling cascade to recruit actin. TARP functions by binding two distinct Rac guanine nucleotide exchange factors (GEFs), Sos1 and Vav2, in a phosphotyrosine-dependent manner. The tyrosine phosphorylation profile of the sequence YEPISTENIYESI within TARP, as well as the transient activation of the phosphatidylinositol 3-kinase (PI3-K), appears to determine which GEF is utilized to activate Rac. The first and second tyrosine residues, when phosphorylated, are utilized by the Sos1/Abi1/Eps8 and Vav2, respectively, with the latter requiring the lipid phosphatidylinositol 3,4,5-triphosphate. Depletion of these critical signaling molecules by siRNA resulted in inhibition of chlamydial invasion to varying degrees, owing to a possible functional redundancy of the two pathways. Collectively, these data implicate TARP in signaling to the actin cytoskeleton remodeling machinery, demonstrating a mechanism by which C. trachomatis invades non-phagocytic cells.

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“…Internalization is accompanied by induction of a microvillus-like structure over a large portion of the host cell in a process that is dependent upon actin polymerization (3) and is mediated through Rac (4). Upon uptake, the organism is sequestered in a membrane-bound compartment, termed the chlamydial inclusion, which rapidly separates from the endocytic pathway and avoids phagolysosomal fusion (30,31). After replicating by binary fission within the ever-enlarging inclusion over a 48-to 72-h time frame, the host cell is lysed and the bacteria are released.…”

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confidence: 99%

Lipid Raft-Mediated Entry Is Not Required for Chlamydia trachomatis Infection of Cultured Epithelial Cells

Gabel¹,

Elwell²,

IJzendoorn

et al. 2004

Infect Immun

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Using pharmacologic and biochemical criteria, we evaluated whether uptake of four different Chlamydia trachomatis serovars, D, E, K, and L2, was dependent upon lipid rafts. Our data suggest that lipid raft-mediated entry is not required for C. trachomatis infection of cultured epithelial cells.Microbes often enter into nonphagocytic cells by usurping normal host cell endocytic pathways. In addition to clathrinmediated endocytosis, various nonclathrin endocytic mechanisms have been identified, including uptake through caveolae, macropinosomes, and a separate constitutive pathway (reviewed in reference 24). These non-clathrin-dependent pathways do not use known coat complexes for cargo recruitment and budding of transport intermediates but are heterogeneous in nature. A subset has been identified that utilizes lipid rafts, specialized dynamic, detergent-resistant regions of the plasma membrane enriched in cholesterol, glycosphingolipids, glycosylphosphatidylinositol-anchored proteins, and some membrane proteins, including caveolin (2, 33). A subtype of lipid rafts, caveolae, has a distinct cave-like morphology in the plasma membrane. Whereas caveolin is widely distributed, caveolae are found in only a few cell types and tissues (16).An increasing number of pathogens, including some bacteria, viruses, and even parasites, have been suggested to enter cells through lipid rafts (reviewed in reference 8). These conclusions are based on pharmacologic, biochemical, and cell biological assays. Inhibition of pathogen entry by drugs that are known to extract or bind to membrane cholesterol, such as methyl-␤-cyclodextrin (M␤CD), filipin, and nystatin, has been used as evidence for lipid raft involvement (35). However, M␤CD has pleiotropic effects, including disruption of clathrinmediated endocytosis, and should not be used as the sole criterion for defining lipid raft-dependent processes. Lipid rafts have also been defined by their resistance to extraction with nonionic detergents at 4°C (hence, they are often referred to as detergent-resistant membranes [DRMs]) and their sedimentation in low-density membrane fractions upon sucrose gradient centrifugation. The colocalization of caveolin or GM1 with pathogens is additional evidence that raft-mediated entry may be involved (7). However, the criterion used to define lipid rafts is at best imprecise and still evolving.Chlamydia spp. are obligate intracellular parasites that are associated with many important human diseases and undergo a dimorphic developmental cycle (13). They alternate between an extracellular, spore-like form, the elementary body (EB), and an intracellular form, the metabolically active but noninfectious reticulate body. The specific bacterial ligand and host receptor(s) that mediate entry are still unclear. Heparan sulfate acts as a bridging molecule for a relatively weak and reversible interaction (12,38,41,42) that is followed by a stronger, more specific binding to an unidentified secondary receptor (5, 11). Internalization is accompanied by induction of a...

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Chlamydia Internalization and Intracellular Fate

Cited by 5 publications

References 86 publications

Intracellular trafficking of Parachlamydia acanthamoebae

Intracellular trafficking of Parachlamydia acanthamoebae

Chlamydial Entry Involves TARP Binding of Guanine Nucleotide Exchange Factors

Lipid Raft-Mediated Entry Is Not Required for Chlamydia trachomatis Infection of Cultured Epithelial Cells

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