Germ Warfare: The Mechanisms of Virulence Factor Delivery

Harper, Jill Reiss; Silhavy, Thomas J.

doi:10.1016/b978-012304220-0/50003-0

Cited by 5 publications

(2 citation statements)

References 232 publications

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“…Pathogenic and non‐pathogenic bacteria utilize this pathway to localize proteins to the cell surface or as the first step in secreting proteins out of the cell (Lee and Schneewind, 2001). Many bacterial pathogens also possess specialized protein export systems dedicated to the secretion of virulence factors (Harper and Silhavy, 2001; Lee and Schneewind, 2001). In some of these systems (Types I and III) the secreted protein does not contain a classical Sec signal sequence.…”

Section: Introductionmentioning

confidence: 99%

SecA2 functions in the secretion of superoxide dismutase A and in the virulence of Mycobacterium tuberculosis

Braunstein

Espinosa

Chan

et al. 2003

Molecular Microbiology

247

270

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Tuberculosis remains a severe worldwide health threat. A thorough understanding of Mycobacterium tuberculosis pathogenesis will facilitate the development of new treatments for tuberculosis. Numerous bacterial pathogens possess specialized protein secretion systems that are dedicated to the export of virulence factors. Mycobacterium tuberculosis is part of a developing group of pathogenic bacteria that share the uncommon property of possessing two secA genes (secA1 and secA2). In mycobacteria, SecA1 is the essential 'housekeeping' SecA protein whereas SecA2 is an accessory secretion factor. Here we demonstrate that SecA2 contributes to the pathogenesis of M. tuberculosis. A deletion of the secA2 gene in M. tuberculosis attenuates the virulence of the organism in mice. By comparing the profile of proteins secreted by wild-type M. tuberculosis and the DeltasecA2 mutant, we identified superoxide dismutase A (SodA) as a protein dependent on SecA2 for secretion. SodA lacks a classical signal sequence for protein export. Our data suggests that SecA2-dependent export is a new type of secretion pathway that is part of a virulence mechanism of M. tuberculosis to elude the oxidative attack of macrophages.

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Section: Introductionmentioning

confidence: 99%

SecA2 functions in the secretion of superoxide dismutase A and in the virulence of Mycobacterium tuberculosis

Braunstein

Espinosa

Chan

et al. 2003

Molecular Microbiology

247

270

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show abstract

“…To reach their extracytoplasmic localization, proteins have to cross one or two membranes. There are various secretion pathways facilitating this process (for recent reviews see Koster et al, 2000;Stathopoulos et al, 2000;Harper and Silhavy, 2001). Two pathways have been described for crossing the inner membrane: the Sec and the Tat pathways.…”

Section: Introductionmentioning

confidence: 99%

Folded HasA inhibits its own secretion through its ABC exporter

Debarbieux

Wandersman

2001

The EMBO Journal

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Gram-negative bacterial proteins secreted by ABC exporters carry a secretion signal in their carboxylic extremities. This characteristic suggests that the polypeptide needs to be fully synthesized before it can be secreted and, therefore, presumably may fold at least in part before its secretion. We investigated the relationship between folding and secretion using HasA, a hemoprotein of Serratia marcescens secreted into the extracellular medium by a dedicated Has ABC exporter. We ®rst demonstrated that when HasA is sequestered in the cytoplasm it can acquire its tertiary structure, as assessed from its capacity to bind heme. The cytoplasmic pool of HasA cannot be secreted and inhibits the secretion of newly synthesized molecules. HasA folding in the cytoplasm was independent of either its capacity to bind heme or the presence of SecB, although SecB is essential for HasA secretion. Our ®ndings indicate a strong coupling between synthesis and secretion in the type I secretion pathway.

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The Genome of the Natural Genetic Engineer Agrobacterium tumefaciens C58

Wood

Setúbal

Kaul

et al. 2001

Science

733

603

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The 5.67-megabase genome of the plant pathogen Agrobacterium tumefaciens C58 consists of a circular chromosome, a linear chromosome, and two plasmids. Extensive orthology and nucleotide colinearity between the genomes of A. tumefaciens and the plant symbiont Sinorhizobium meliloti suggest a recent evolutionary divergence. Their similarities include metabolic, transport, and regulatory systems that promote survival in the highly competitive rhizosphere; differences are apparent in their genome structure and virulence gene complement. Availability of the A. tumefaciens sequence will facilitate investigations into the molecular basis of pathogenesis and the evolutionary divergence of pathogenic and symbiotic lifestyles.

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Germ Warfare: The Mechanisms of Virulence Factor Delivery

Cited by 5 publications

References 232 publications

SecA2 functions in the secretion of superoxide dismutase A and in the virulence of Mycobacterium tuberculosis

SecA2 functions in the secretion of superoxide dismutase A and in the virulence of Mycobacterium tuberculosis

Folded HasA inhibits its own secretion through its ABC exporter

The Genome of the Natural Genetic Engineer Agrobacterium tumefaciens C58

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