Emerging and re-emerging rickettsioses: endothelial cell infection and early disease events

Walker, David H.; Ismail, Nahed

doi:10.1038/nrmicro1866

Cited by 248 publications

(258 citation statements)

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“…However, we are aware that the species definition for Rickettsia remains a controversial issue, without a major consensus among rickettsiologists (Walker & Ismail 2008, Fournier & Raoult 2009, Goddard 2009). …”

Section: Discussionmentioning

confidence: 99%

Spotted fever group Rickettsia infecting ticks (Acari: Ixodidae) in the state of Santa Catarina, Brazil

Medeiros

Souza

Moura

et al. 2011

Mem. Inst. Oswaldo Cruz

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Section: Discussionmentioning

confidence: 99%

Spotted fever group Rickettsia infecting ticks (Acari: Ixodidae) in the state of Santa Catarina, Brazil

Medeiros

Souza

Moura

et al. 2011

Mem. Inst. Oswaldo Cruz

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“…Rickettsiae are obligate intracellular Gram-negative pathogens that are transmitted to humans via arthropod vectors, such as ticks, fleas, and lice (4). Rickettsia species are responsible for a number of severe human diseases, including typhus and spotted fever (5).…”

mentioning

confidence: 99%

Rickettsia Sca2 has evolved formin-like activity through a different molecular mechanism

Madasu

Suarez

Kast

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Sca2 (surface cell antigen 2) is the only bacterial protein known to promote both actin filament nucleation and profilin-dependent elongation, mimicking eukaryotic formins to assemble actin comet tails for Rickettsia motility. We show that Sca2's functional mimicry of formins is achieved through a unique mechanism. Unlike formins, Sca2 is monomeric, but has N-and C-terminal repeat domains (NRD and CRD) that interact with each other for processive barbed-end elongation. The crystal structure of NRD reveals a previously undescribed fold, consisting of helix-loop-helix repeats arranged into an overall crescent shape. CRD is predicted to share this fold and might form together with NRD, a doughnut-shaped formin-like structure. In between NRD and CRD, proline-rich sequences mediate the incorporation of profilin-actin for elongation, and WASP-homology 2 (WH2) domains recruit actin monomers for nucleation. Sca2's α-helical fold is unusual among Gram-negative autotransporters, which overwhelmingly fold as β-solenoids. Rickettsia has therefore "rediscovered" formin-like actin nucleation and elongation.passenger domain | translocator domain | spotted fever M any bacterial pathogens use the actin cytoskeleton of host eukaryotic cells for invasion and motility (1, 2). In so doing, bacteria often resort to mimicry by expressing proteins that adopt core functions of key actin cytoskeletal components, particularly actin filament nucleation and elongation factors. However, bacterial proteins tend to bypass the elaborate regulatory networks characteristic of their eukaryotic counterparts, offering a rare opportunity to dissect their functions within a simplified system (2, 3), with implications for our understanding of pathogenicity and the eukaryotic actin cytoskeleton alike.Rickettsiae are obligate intracellular Gram-negative pathogens that are transmitted to humans via arthropod vectors, such as ticks, fleas, and lice (4). Rickettsia species are responsible for a number of severe human diseases, including typhus and spotted fever (5). The spotted fever group, including Rickettsia parkeri, Rickettsia conorii, Rickettsia rickettsii, and over 20 other species throughout the world, uses the host-cell actin cytoskeleton to spread inter-and intracellularly. Similar to Listeria and Shigella, Rickettsia forms actin comet tails to propel its movement. However, the actin tails of Rickettsia consist of long and unbranched actin filaments, whereas those of Listeria and Shigella contain shorter and densely branched filaments (6, 7). These morphological differences stem from different molecular mechanisms for comet tail formation by these pathogens. Listeria and Shigella rely heavily on the activity of the host Arp2/3 complex that localizes uniformly along their tails (6). Although the Arp2/3 complex, activated by either host nucleation promoting factors (8) or the Rickettsia surface protein RickA (9, 10), is necessary for Rickettsia invasion (11), it is absent from Rickettsia tails (6). Another protein, Sca2 (surface cell antigen 2), has ...

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“…Like all Gram-negative bacteria, rickettsiae contain several outer membrane proteins (OMPs) 2 that are found in the outer leaflet of the outer membrane. OMPs provide the first line of communication with the extracellular environment, with prominent roles in molecular transport and bacterial infection and pathogenesis (3,4).…”

mentioning

confidence: 99%

“…Rickettsiae are obligatory intracellular infectious Gram-negative bacteria that are responsible for major rickettsiosis, which includes epidemic and endemic typhus, spotted fever, and scrub typhus (1,2). Like all Gram-negative bacteria, rickettsiae contain several outer membrane proteins (OMPs) 2 that are found in the outer leaflet of the outer membrane.…”

mentioning

confidence: 99%

Multimethylation of Rickettsia OmpB Catalyzed by Lysine Methyltransferases

Abeykoon

Wang

Chao

et al. 2014

Journal of Biological Chemistry

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Background: Methylation of OmpB has been implicated in rickettsial virulence. Results: Native OmpBs purified from Rickettsia contain mono-and trimethyllysine at specific locations that coincide with those catalyzed by methyltransferases in vitro. Conclusion: The number of trimethyllysine clusters in OmpBs correlates with degree of virulence. Significance: This study provides new insight into methylation of OmpB and its correlation with virulence.

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Emerging and re-emerging rickettsioses: endothelial cell infection and early disease events

Cited by 248 publications

References 114 publications

Spotted fever group Rickettsia infecting ticks (Acari: Ixodidae) in the state of Santa Catarina, Brazil

Spotted fever group Rickettsia infecting ticks (Acari: Ixodidae) in the state of Santa Catarina, Brazil

Rickettsia Sca2 has evolved formin-like activity through a different molecular mechanism

Multimethylation of Rickettsia OmpB Catalyzed by Lysine Methyltransferases

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