A protein linkage map of the ESAT-6 secretion system 1 (ESX-1) of Mycobacterium tuberculosis

Teutschbein, Janka; Schumann, G.; Möllmann, Ute; Grabley, Susanne; Cole, Stewart T.; Münder, Thomas

doi:10.1016/j.micres.2006.11.016

Cited by 64 publications

(50 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…24 The inactivation of PPE68 leads to an enhancement of the secretion of ESAT-6, suggesting that PPE68 is likely to have a role and participates in the control of secretion by the type VII secretion apparatus. 17 Similar observation has been made regarding the role of PPE68 protein by other groups. 26 This raises an important question: why the inactivation of PPE68, associated with increased secretion of ESAT-6, decreases the necrotic cell death as observed in our assays.…”

Section: Discussionsupporting

confidence: 81%

“…23 Recent studies have demonstrated that PPE68 is a significant immunogenic component of RD1 and most likely plays an important role in Mtb pathogenicity. 24 The profile of PPE68 interacting Mtb proteins Studies provide evidence that PPE68 interacts with multiple components of the ESX-1 machinery 17,25 and results further indicate that disruption of PPE68 is associated with increased secretion of ESAT-6 effector protein, suggesting the possible role of PPE68 as a gating protein during the type VII-dependent (2), Rv1093/glyA1 (3), Rv1388/mihF (4), Rv1837c/glcB (5), Rv2220/glnA1 (6) and Rv2626c (7) were confirmed using a yeast 2-hybrid system. To test the specificity of PPE68 interaction to target Mtb proteins, the yeast reporter strain containing the bait pGBKT7:PPE4 and pGBKT7:PPE27 constructs were screened against the selected Mtb gene constructs in pGADT7 vector; The yeast zygotes that grew on quadruple dropout medium SD/-Ade/-His/-Leu/-Trp supplemented with X-a-Gal and Aureobasidin A (QDO/X/A) and turned blue in color were considered positive.…”

Section: Necrosis Deficient Mutants Are Associated With Delayed Activmentioning

confidence: 99%

“…16 The fact is that ESAT-6 and CFP-10 proteins are secreted inside of macrophages soon after phagocytosis, but necrosis and eventual exit from the cell does not happen until several days after infection. In addition, both proteins have been associated with a number of virulence-related mechanisms [17][18][19] and there is a possibility that knockout mutants would have additional characteristics that might depend on ESAT-6 and CFP-10 indirectly. Our laboratory has demonstrated that Mtb partially inhibits macrophage apoptosis.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mycobacterium tuberculosisPPE68 and Rv2626c genes contribute to the host cell necrosis and bacterial escape from macrophages

2015

View full text Add to dashboard Cite

Alveolar macrophages are the main line of innate immune response against M. tuberculosis (Mtb) infection. However, these cells serve as the major intracellular niche for Mtb enhancing its survival, replication and, later on, cell-to-cell spread. Mtb-associated cytotoxicity of macrophages has been well documented, but limited information exists about mechanisms by which the pathogen induces cell necrosis. To identify virulence factors involved in the induction of necrosis, we screened 5,000 transposon mutants of Mtb for clones that failed to promote the host cell necrosis in a similar manner as the wild-type bacterium. Five Mtb mutants were identified as potential candidates inducing significantly lower levels of THP-1 cell damage in contrast to the H37Rv wild-type infection. Reduced levels of the cell damage by necrosis deficient mutants (NDMs) were also associated with delayed damage of mitochondrial membrane permeability when compared with the wild-type infection over time. Two knockout mutants of the Rv3873 gene, encoding a cell wall PPE68 protein of RD1 region, were identified out of 5 NDMs. Further investigation lead to the observation that PPE68 protein interacts and exports several unknown or known surface/secreted proteins, among them Rv2626c is associated with the host cell necrosis. When the Rv2626c gene is deleted from the genome of Mtb, the bacterium displays significantly less necrosis in THP-1 cells and, conversely, the overexpression of Rv2626c promotes the host cell necrosis at early time points of infections in contrast to the wild-type strain.

show abstract

Section: Discussionsupporting

confidence: 81%

Section: Necrosis Deficient Mutants Are Associated With Delayed Activmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mycobacterium tuberculosisPPE68 and Rv2626c genes contribute to the host cell necrosis and bacterial escape from macrophages

2015

View full text Add to dashboard Cite

show abstract

“…Serum CFP-10 was detectable at lower concentrations than ESAT-6, perhaps owing to variable expression levels of ESAT-6 and CFP-10 in different strains of Mtb (40,41). However, host β2 microglobulin also has been reported to bind ESAT-6 to mask a tryptic cleavage site (amino acids 90-95) required for the 1,900.95 m/z ESAT-6 peptide (16,42), and thus may inhibit ESAT-6 cleavage to decrease the apparent serum ESAT-6 levels in our assay.…”

Section: Discussionmentioning

confidence: 99%

Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring

Liu

Zhao

Fan

et al. 2017

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

View full text Add to dashboard Cite

Tuberculosis (TB) is a major global health threat, resulting in an urgent unmet need for a rapid, non-sputum-based quantitative test to detect active Mycobacterium tuberculosis (Mtb) infections in clinically diverse populations and quickly assess Mtb treatment responses for emerging drug-resistant strains. We have identified Mtb-specific peptide fragments and developed a method to rapidly quantify their serum concentrations, using antibody-labeled and energy-focusing porous discoidal silicon nanoparticles (nanodisks) and high-throughput mass spectrometry (MS) to enhance sensitivity and specificity. NanoDisk-MS diagnosed active Mtb cases with high sensitivity and specificity in a case-control study with cohorts reflecting the complexity of clinical practice. Similar robust sensitivities were obtained for cases of culture-positive pulmonary TB (PTB; 91.3%) and extrapulmonary TB (EPTB; 92.3%), and the sensitivities obtained for culture-negative PTB (82.4%) and EPTB (75.0%) in HIV-positive patients significantly outperformed those reported for other available assays. NanoDisk-MS also exhibited high specificity (87.1-100%) in both healthy and high-risk groups. Absolute quantification of serum Mtb antigen concentration was informative in assessing responses to antimycobacterial treatment. Thus, a NanoDisk-MS assay approach could significantly improve the diagnosis and management of active TB cases, and perhaps other infectious diseases as well.D espite international efforts and initiatives, tuberculosis (TB) remains a major public health concern worldwide, associated with high morbidity and mortality (1, 2). Detecting active TB cases and monitoring their responses to therapy are fraught with challenges, relying predominantly on microbiologic techniques that use sputum samples, including acid-fast Bacillus (AFB) smear microscopy-widely used as an initial test for TB diagnosis (3, 4)-and Mycobacterium tuberculosis (Mtb) culture, both of which have only moderate sensitivity and specificity and a long turnaround time (5, 6). Moreover, sputum samples are difficult to obtain after symptom improvement, and often are not diagnostically useful for extrapulmonary TB (EPTB) cases. The PCR-based Xpert MTB/RIF sputum assay was introduced to improve the speed and specificity of TB diagnosis, but this assay has poor sensitivity under low bacterial loads and cannot distinguish live and nonviable Mtb contributions (7,8). A recent World Health Organization (WHO) policy update acknowledged the low quality of evidence supporting the use of Xpert MTB/RIF to diagnose EPTB (9). Diagnostic challenges can be further magnified in patients coinfected with HIV and TB (10). In addition, none of these techniques provides quantitative results that can be used to monitor treatment effects (11,12).Consequently, there is an urgent need, highlighted as a high priority in a recent WHO consensus report (13), for the development of rapid, quantitative, non-sputum-based biomarker tests that do not require bacterial isolation to detect active TB (13). Non-s...

show abstract

“…EccA is an ATPase that may be involved in dissociating the EspG-PPE interaction because (i) EccA proteins are only encoded in ESX gene clusters that also encode PE and PPE proteins, (ii) EccA mutants accumulate PPE-bound EspG (22), and (iii) EccA interacts with both PPE protein (35) and EspG (SI Appendix, Fig. S12) in yeast two-hybrid assays.…”

Section: Espg Encoded In the Esx-5 Gene Cluster Of Mtb Interacts Exclmentioning

confidence: 99%

Structure of a PE–PPE–EspG complex fromMycobacterium tuberculosisreveals molecular specificity of ESX protein secretion

Ekiert

Cox

2014

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

105

131

View full text Add to dashboard Cite

Nearly 10% of the coding capacity of the Mycobacterium tuberculosis genome is devoted to two highly expanded and enigmatic protein families called PE and PPE, some of which are important virulence/immunogenicity factors and are secreted during infection via a unique alternative secretory system termed "type VII." How PE-PPE proteins function during infection and how they are translocated to the bacterial surface through the five distinct type VII secretion systems [ESAT-6 secretion system (ESX)] of M. tuberculosis is poorly understood. Here, we report the crystal structure of a PE-PPE heterodimer bound to ESX secretion-associated protein G (EspG), which adopts a novel fold. This PE-PPE-EspG complex, along with structures of two additional EspGs, suggests that EspG acts as an adaptor that recognizes specific PE-PPE protein complexes via extensive interactions with PPE domains, and delivers them to ESX machinery for secretion. Surprisingly, secretion of most PE-PPE proteins in M. tuberculosis is likely mediated by EspG from the ESX-5 system, underscoring the importance of ESX-5 in mycobacterial pathogenesis. Moreover, our results indicate that PE-PPE domains function as cis-acting targeting sequences that are read out by EspGs, revealing the molecular specificity for secretion through distinct ESX pathways.tuberculosis | protein secretion | antigenic variation | virulence factor | host-pathogen interactions

show abstract

A protein linkage map of the ESAT-6 secretion system 1 (ESX-1) of Mycobacterium tuberculosis

Cited by 64 publications

References 23 publications

Mycobacterium tuberculosisPPE68 and Rv2626c genes contribute to the host cell necrosis and bacterial escape from macrophages

Mycobacterium tuberculosisPPE68 and Rv2626c genes contribute to the host cell necrosis and bacterial escape from macrophages

Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring

Structure of a PE–PPE–EspG complex fromMycobacterium tuberculosisreveals molecular specificity of ESX protein secretion

Contact Info

Product

Resources

About