Backbone chemical shift assignment and dynamics of the N-terminal domain of ClpB from Francisella tularensis type VI secretion system

AbstractThe Hsp100 family member ClpB is a protein disaggregase which solubilizes and reactivates stress-induced protein aggregates in cooperation with the DnaK/Hsp70 chaperone system. In the pathogenic bacterium Francisella tularensis, ClpB is involved in type VI secretion system (T6SS) disassembly through depolymerization of the IglA-IglB sheath. This leads to recycling and reassembly of T6SS components and this process is essential for the virulence of the bacterium. Here we report the backbone chemical shift assignments and 15N relaxation-based backbone dynamics of the N-terminal substrate-binding domain of ClpB (1-156).

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Unique Substrates Secreted by the Type VI Secretion System of Francisella tularensis during Intramacrophage Infection

PLoS ONE ◽

10.1371/journal.pone.0050473 ◽

2012 ◽

Vol 7 (11) ◽

pp. e50473 ◽

Cited By ~ 43

Author(s):

Jeanette E. Bröms ◽

Lena Meyer ◽

Kun Sun ◽

Moa Lavander ◽

Anders Sjöstedt

Keyword(s):

Francisella Tularensis ◽

Secretion System ◽

Type Vi Secretion System ◽

Type Vi Secretion

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Faculty Opinions recommendation of Unique substrates secreted by the type VI secretion system of Francisella tularensis during intramacrophage infection.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717967824.793467518 ◽

2012 ◽

Author(s):

Barbara Mann

Keyword(s):

Francisella Tularensis ◽

Secretion System ◽

Type Vi Secretion System ◽

Type Vi Secretion

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IglG and IglI of the Francisella Pathogenicity Island Are Important Virulence Determinants of Francisella tularensis LVS

Infection and Immunity ◽

10.1128/iai.01344-10 ◽

2011 ◽

Vol 79 (9) ◽

pp. 3683-3696 ◽

Cited By ~ 32

Author(s):

Jeanette E. Bröms ◽

Moa Lavander ◽

Lena Meyer ◽

Anders Sjöstedt

Keyword(s):

Francisella Tularensis ◽

Host Response ◽

Systemic Infection ◽

Pathogenicity Island ◽

Secretion System ◽

Virulence Determinants ◽

Negative Bacterium ◽

Type Vi Secretion System ◽

Content Type ◽

Type Vi Secretion

ABSTRACTThe Gram-negative bacteriumFrancisella tularensisis the causative agent of tularemia, a disease intimately associated with the multiplication of the bacterium within host macrophages. This in turn requires the expression ofFrancisellapathogenicity island (FPI) genes, believed to encode a type VI secretion system. While the exact functions of many of the components have yet to be revealed, some have been found to contribute to the ability ofFrancisellato cause systemic infection in mice as well as to prevent phagolysosomal fusion and facilitate escape into the host cytosol. Upon reaching this compartment, the bacterium rapidly multiplies, inhibits activation of the inflammasome, and ultimately causes apoptosis of the host cell. In this study, we analyzed the contribution of the FPI-encoded proteins IglG, IglI, and PdpE to the aforementioned processes inF. tularensisLVS. The ΔpdpEmutant behaved similarly to the parental strain in all investigated assays. In contrast, ΔiglGand ΔiglImutants, although they were efficiently replicating in J774A.1 cells, both exhibited delayed phagosomal escape, conferred a delayed activation of the inflammasome, and exhibited reduced cytopathogenicity as well as marked attenuation in the mouse model. Thus, IglG and IglI play key roles for modulation of the intracellular host response and also for the virulence ofF. tularensis.

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