Anaplasma phagocytophilum APH_0032 is expressed late during infection and localizes to the pathogen-occupied vacuolar membrane

Huang, Bernice; Troese, Matthew J.; Howe, Dale; Ye, Shaojing; Sims, Jonathan T.; Heinzen, Robert A.; Borjesson, Dori L.; Carlyon, Jason A.

doi:10.1016/j.micpath.2010.06.009

Cited by 48 publications

(99 citation statements)

References 55 publications

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“…A search against the Pfam domain database revealed that, as expected, all AnkA sequences detected during the present study contained ankyrin repeats. Furthermore, all of them showed a putative T4SS signal sequence (51) in line with the fact that AnkA is translocated by heterologous T4SSs (29,34). AnkA sequences of all four clusters contained at their C-terminal end several tyrosine kinase phosphorylation sites predicted by Scansite (http: //scansite.mit.edu/).…”

Section: Resultsmentioning

confidence: 62%

“…Although the exact function of AnkA has not been determined yet (50), its C-terminal end has been shown to be secreted by the VirB/ VirD4-dependent type IV secretion system (T4SS) of Agrobacterium tumefaciens (34) and the Dot/Icm type T4SS of Legionella pneumophila (29). After translocation, AnkA is tyrosine phosphorylated by the host cell tyrosine kinases Src (31) and Abl (34).…”

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confidence: 99%

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Distinct Host Species Correlate with Anaplasma phagocytophilum ankA Gene Clusters

et al. 2011

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Anaplasma phagocytophilum is a Gram-negative, tick-transmitted, obligate intracellular bacterium that elicits acute febrile diseases in humans and domestic animals. In contrast to the United States, human granulocytic anaplasmosis seems to be a rare disease in Europe despite the initial recognition of A. phagocytophilum as the causative agent of tick-borne fever in European sheep and cattle. Considerable strain variation has been suggested to occur within this species, because isolates from humans and animals differed in their pathogenicity for heterologous hosts. In order to explain host preference and epidemiological diversity, molecular characterization of A. phagocytophilum strains has been undertaken. Most often the 16S rRNA gene was used, but it might be not informative enough to delineate distinct genotypes of A. phagocytophilum. Previously, we have shown that A. phagocytophilum strains infecting Ixodes ricinus ticks are highly diverse in their ankA genes. Therefore, we sequenced the 16S rRNA and ankA genes of 194 A. phagocytophilum strains from humans and several animal species. Whereas the phylogenetic analysis using 16S rRNA gene sequences was not meaningful, we showed that distinct host species correlate with A. phagocytophilum ankA gene clusters.

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Section: Resultsmentioning

confidence: 62%

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confidence: 99%

Distinct Host Species Correlate with Anaplasma phagocytophilum ankA Gene Clusters

et al. 2011

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“…L. pneumophila has been invaluable in identifying C. burnetii T4SS substrates (35,48,67). However, direct demonstration of effector secretion by C. burnetii would be ideal.…”

Section: Resultsmentioning

confidence: 99%

TheCoxiella burnetiiCryptic Plasmid Is Enriched in Genes Encoding Type IV Secretion System Substrates

et al. 2011

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The intracellular bacterial pathogen Coxiella burnetii directs biogenesis of a phagolysosome-like parasitophorous vacuole (PV), in which it replicates. The organism encodes a Dot/Icm type IV secretion system (T4SS) predicted to deliver to the host cytosol effector proteins that mediate PV formation and other cellular events. All C. burnetii isolates carry a large, autonomously replicating plasmid or have chromosomally integrated plasmid-like sequences (IPS), suggesting that plasmid and IPS genes are critical for infection. Bioinformatic analyses revealed two candidate Dot/Icm substrates with eukaryotic-like motifs uniquely encoded by the QpH1 plasmid from the Nine Mile reference isolate. CpeC, containing an F-box domain, and CpeD, possessing kinesin-related and coiled-coil regions, were secreted by the closely related Legionella pneumophila Dot/Icm T4SS. An additional QpH1-specific gene, cpeE, situated in a predicted operon with cpeD, also encoded a secreted effector. Further screening revealed that three hypothetical proteins (CpeA, CpeB, and CpeF) encoded by all C. burnetii plasmids and IPS are Dot/Icm substrates. By use of new genetic tools, secretion of plasmid effectors by C. burnetii during host cell infection was confirmed using ␤-lactamase and adenylate cyclase translocation assays, and a C-terminal secretion signal was identified. When ectopically expressed in HeLa cells, plasmid effectors trafficked to different subcellular sites, including autophagosomes (CpeB), ubiquitinrich compartments (CpeC), and the endoplasmic reticulum (CpeD). Collectively, these results suggest that C. burnetii plasmid-encoded T4SS substrates play important roles in subversion of host cell functions, providing a plausible explanation for the absolute maintenance of plasmid genes by this pathogen.

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“…We detected expression of 27 hypothetical proteins in tick salivary glands by proteomics or RNA-seq (Table 3 and Table 4). Some of these proteins have previously been characterized in HL-60 cultures for their roles in A. phagocytophilum infection (14,15,34) or identified as immunoreactive proteins (24). Two hypothetical proteins, APH_0220 and APH_0792, were classified as among the most abundant in the HL-60 culture proteome (23).…”

Section: Resultsmentioning

confidence: 99%

Postgenomic Analyses Reveal Development of Infectious Anaplasma phagocytophilum during Transmission from Ticks to Mice

2012

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Obligate intracellular bacteria of the Rickettsiales order have evolved to colonize both arthropod and mammalian hosts, but few details are known about the bacterial adaptations that occur during transmission from blood-feeding arthropods to mammals. Here we apply proteomics and transcriptome sequencing to Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis, in Ixodes scapularis tick salivary glands, to detect proteins or genes expressed by the pathogen during transmission feeding by the tick. We detected expression of 139 genes, representing 11% of the open reading frames (ORFs) in the A. phagocytophilum genome. The predominant categories of proteins were ribosomal proteins, cell surface proteins, chaperones, and uncharacterized proteins. There was no evidence of DNA replication enzymes, suggesting that most of the A. phagocytophilum cells were no longer dividing. Instead, protein expression reflected conversion to the extracellular, infectious "dense-core" (DC) form. High expression of a DC-specific marker, APH_1235, further suggested this developmental transition in ticks. We showed that blocking APH_1235 with antibodies reduced A. phagocytophilum infection levels in mammalian cell culture. This work represents a starting point for clarifying essential proteins expressed by A. phagocytophilum during transmission from ticks to mammals and demonstrates that the abundantly expressed, DC-associated APH_1235 protein is important during in vivo infection by A. phagocytophilum.

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Anaplasma phagocytophilum APH_0032 is expressed late during infection and localizes to the pathogen-occupied vacuolar membrane

Cited by 48 publications

References 55 publications

Distinct Host Species Correlate with Anaplasma phagocytophilum ankA Gene Clusters

Distinct Host Species Correlate with Anaplasma phagocytophilum ankA Gene Clusters

TheCoxiella burnetiiCryptic Plasmid Is Enriched in Genes Encoding Type IV Secretion System Substrates

Postgenomic Analyses Reveal Development of Infectious Anaplasma phagocytophilum during Transmission from Ticks to Mice

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