scholarly journals Immunodominant Regions of a Chlamydia trachomatis Type III Secretion Effector Protein, Tarp

2010 ◽  
Vol 17 (9) ◽  
pp. 1371-1376 ◽  
Author(s):  
Jie Wang ◽  
Yingqian Zhang ◽  
Ping Yu ◽  
Guangming Zhong
Keyword(s):  
Amino Acids ◽  
Chlamydia Trachomatis ◽  
Type Iii Secretion ◽  
Fusion Proteins ◽  
Host Cells ◽  
Ocular Tissue ◽  
Effector Protein ◽  
Immunodominant Region ◽  
Type Iii ◽  
Type Iii Secretion Effector

ABSTRACT We have previously shown that individuals infected with Chlamydia trachomatis can develop a robust antibody response to a Chlamydia type III secretion effector protein called Tarp and that immunization with Tarp induces protection against challenge infection in mice. The current study aimed to map the immunodominant regions of the Tarp protein by expressing 11 fragments of Tarp as glutathione S-transferase (GST) fusion proteins and detecting the reactivity of these fusion proteins with antisera from patients infected with C. trachomatis in the urogenital tract or in the ocular tissue and from rabbits immunized with C. trachomatis organisms. A major immunodominant region was strongly recognized by all antibodies. This region covers amino acids 152 to 302, consisting of three repeats (amino acids 152 to 201, 202 to 251, and 252 to 302). Each of the repeats contains multiple tyrosine residues that are phosphorylated by host cell kinases when Tarp is injected into host cells. Several other minor immunodominant regions were also identified, including those comprising amino acids 1 to 156, 310 to 431, and 582 to 682 (recognized by antisera from both humans and rabbits), that comprising amino acids 425 to 581 (recognized only by human antisera), and that comprising amino acids 683 to 847 (preferentially recognized by rabbit antisera). This immunodominance was also confirmed by the observations that six out of the nine monoclonal antibodies (MAbs) bound to the major immunodominant region and that the other three each bound to one of the minor fragments, comprising amino acids 1 to 119, 120 to 151, and 310 to 431. The antigenicity analyses have provided important information for further understanding the structure and function of Tarp.

scholarly journals SepL Resembles an Aberrant Effector in Binding to a Class 1 Type III Secretion Chaperone and Carrying an N-Terminal Secretion Signal

2010 ◽  
Vol 192 (22) ◽  
pp. 6093-6098 ◽  
Author(s):  
Rasha Younis ◽  
Lewis E. H. Bingle ◽  
Sarah Rollauer ◽  
Diana Munera ◽  
Stephen J. Busby ◽  
...  
Keyword(s):  
Amino Acids ◽  
Type Iii Secretion ◽  
Fusion Proteins ◽  
Effector Protein ◽  
Type Iii ◽  
Secretion Signal ◽  
Class 1 ◽  
Secretion Chaperone

ABSTRACT Here we show that the type III secretion gatekeeper protein SepL resembles an aberrant effector protein in binding to a class 1 type III secretion chaperone (Orf12, here renamed CesL). We also show that short N-terminal fragments (≤70 amino acids) from SepL are capable of targeting fusion proteins for secretion and translocation.

scholarly journals Chronic Effects of a Salmonella Type III Secretion Effector Protein AvrA In Vivo

PLoS ONE ◽  
2010 ◽  
Vol 5 (5) ◽  
pp. e10505 ◽  
Author(s):  
Rong Lu ◽  
Shaoping Wu ◽  
Xingyin Liu ◽  
Yinglin Xia ◽  
Yong-guo Zhang ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Effector Protein ◽  
Type Iii ◽  
Chronic Effects ◽  
Type Iii Secretion Effector

scholarly journals Global impact of Salmonella type III secretion effector SteA on host cells

2014 ◽  
Vol 449 (4) ◽  
pp. 419-424 ◽  
Author(s):  
Elena Cardenal-Muñoz ◽  
Gabriel Gutiérrez ◽  
Francisco Ramos-Morales
Keyword(s):  
Type Iii Secretion ◽  
Host Cells ◽  
Global Impact ◽  
Type Iii ◽  
Type Iii Secretion Effector

scholarly journals Structure and Dynamics of Type III Secretion Effector Protein ExoU As determined by SDSL-EPR Spectroscopy in Conjunction with De Novo Protein Folding

ACS Omega ◽  
2017 ◽  
Vol 2 (6) ◽  
pp. 2977-2984 ◽  
Author(s):  
Axel W. Fischer ◽  
David M. Anderson ◽  
Maxx H. Tessmer ◽  
Dara W. Frank ◽  
Jimmy B. Feix ◽  
...  
Keyword(s):  
Protein Folding ◽  
Epr Spectroscopy ◽  
Type Iii Secretion ◽  
De Novo ◽  
Effector Protein ◽  
Type Iii ◽  
Structure And Dynamics ◽  
Type Iii Secretion Effector

scholarly journals Effect of the O-Antigen Length of Lipopolysaccharide on the Functions of Type III Secretion Systems in Salmonella enterica

2009 ◽  
Vol 77 (12) ◽  
pp. 5458-5470 ◽  
Author(s):  
Stefanie U. Hölzer ◽  
Markus C. Schlumberger ◽  
Daniela Jäckel ◽  
Michael Hensel
Keyword(s):  
Type Iii Secretion ◽  
Salmonella Enterica ◽  
Defense Mechanisms ◽  
Host Cells ◽  
Effector Protein ◽  
Secretion Systems ◽  
Type Iii ◽  
O Antigen ◽  
T3ss Effector ◽  
Type Iii Secretion Systems

ABSTRACT The virulence of Salmonella enterica critically depends on the functions of two type III secretion systems (T3SS), with the Salmonella pathogenicity island 1 (SPI1)-encoded T3SS required for host cell invasion and the SPI2-T3SS enabling Salmonella to proliferate within host cells. A further T3SS is required for the assembly of the flagella. Most serovars of Salmonella also possess a lipopolysaccharide with a complex O-antigen (OAg) structure. The number of OAg units attached to the core polysaccharide varies between 16 and more than 100 repeats, with a trimodal distribution. This work investigated the correlation of the OAg length with the functions of the SPI1-T3SS and the SPI2-T3SS. We observed that the number of repeats of OAg units had no effect on bacterial motility. The interaction of Salmonella with epithelial cells was altered if the OAg structure was changed by mutations in regulators of OAg. Strains defective in synthesis of very long or long and very long OAg species showed increased translocation of a SPI1-T3SS effector protein and increased invasion. Invasion of a strain entirely lacking OAg was increased, but this mutant strain also showed increased adhesion. In contrast, translocation of a SPI2-T3SS effector protein and intracellular replication were not affected by modification of the OAg length. Mutant strains lacking the entire OAg or long and very long OAg were highly susceptible to complement killing. These observations indicate that the architecture of the outer membrane of Salmonella is balanced to permit sufficient T3SS function but also to confer optimal protection against antimicrobial defense mechanisms.

scholarly journals Role of the Salmonella Pathogenicity Island 1 (SPI-1) Protein InvB in Type III Secretion of SopE and SopE2, Two Salmonella Effector Proteins Encoded Outside of SPI-1

2003 ◽  
Vol 185 (23) ◽  
pp. 6950-6967 ◽  
Author(s):  
Kristin Ehrbar ◽  
Andrea Friebel ◽  
Samuel I. Miller ◽  
Wolf-Dietrich Hardt
Keyword(s):  
Type Iii Secretion ◽  
Inflammatory Responses ◽  
Pathogenicity Island ◽  
Effector Proteins ◽  
Host Cells ◽  
Effector Protein ◽  
Dependent Manner ◽  
Type Iii ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica subspecies 1 serovar Typhimurium encodes a type III secretion system (TTSS) within Salmonella pathogenicity island 1 (SPI-1). This TTSS injects effector proteins into host cells to trigger invasion and inflammatory responses. Effector proteins are recognized by the TTSS via signals encoded in their N termini. Specific chaperones can be involved in this process. The chaperones InvB, SicA, and SicP are encoded in SPI-1 and are required for transport of SPI-1-encoded effectors. Several key effector proteins, like SopE and SopE2, are located outside of SPI-1 but are secreted in an SPI-1-dependent manner. It has not been clear how these effector proteins are recognized by the SPI-1 TTSS. Using pull-down and coimmunoprecipitation assays, we found that SopE is copurified with InvB, the known chaperone for the SPI-1-encoded effector protein Sip/SspA. We also found that InvB is required for secretion and translocation of SopE and SopE2 and for stabilization of SopE2 in the bacterial cytosol. Our data demonstrate that effector proteins encoded within and outside of SPI-1 use the same chaperone for secretion via the SPI-1 TTSS.

scholarly journals Bioinformatics Correctly Identifies Many Type III Secretion Substrates in the Plant Pathogen Pseudomonas syringae and the Biocontrol Isolate P. fluorescens SBW25

2005 ◽  
Vol 18 (8) ◽  
pp. 877-888 ◽  
Author(s):  
Boris A. Vinatzer ◽  
Joanna Jelenska ◽  
Jean T. Greenberg
Keyword(s):  
Amino Acids ◽  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Type Iii Secretion ◽  
Host Cells ◽  
Protein Accumulation ◽  
Large Set ◽  
Virulence Proteins ◽  
Type Iii ◽  
C Terminus

The plant pathogen Pseudomonas syringae causes disease by secreting a potentially large set of virulence proteins called effectors directly into host cells, their environment, or both, using a type III secretion system (T3SS). Most P.syringae effectors have a common upstream element called the hrp box, and their N-terminal regions have amino acids biases, features that permit their bioinformatic prediction. One of the most prominent biases is a positive serine bias. We previously used the truncated AvrRpt281–255 effector containing a serine-rich stretch from amino acids 81 to 100 as a T3SS reporter. Region 81 to 100 of this reporter does not contribute to the secretion or translocation of AvrRpt2 or to putative effector protein chimeras. Rather, the serine-rich region from the N-terminus of AvrRpt2 is important for protein accumulation in bacteria. Most of the N-terminal region (amino acids 15 to 100) is not essential for secretion in culture or delivery to plants. However, portions of this sequence may increase the efficiency of AvrRpt2 secretion, delivery to plants, or both. Two effectors previously identified with the AvrRpt281–255 reporter were secreted in culture independently of AvrRpt2, validating the use of the C terminus of AvrRpt2 as a T3SS reporter. Finally, using the reduced AvrRpt2101–255 reporter, we confirmed seven predicted effectors from P. syringae pv. tomato DC3000, four from P. syringae pv. syringae B728a, and two from P. fluorescens SBW25.

scholarly journals Type III secretion system effector proteins are mechanically labile

2021 ◽  
Vol 118 (12) ◽  
pp. e2019566118
Author(s):  
Marc-André LeBlanc ◽  
Morgan R. Fink ◽  
Thomas T. Perkins ◽  
Marcelo C. Sousa
Keyword(s):  
Type Iii Secretion ◽  
Protein Unfolding ◽  
Effector Proteins ◽  
Host Cells ◽  
Effector Protein ◽  
Secretion Systems ◽  
Channel Diameter ◽  
Type Iii ◽  
Pass Through ◽  
Partially Unfolded

Multiple gram-negative bacteria encode type III secretion systems (T3SS) that allow them to inject effector proteins directly into host cells to facilitate colonization. To be secreted, effector proteins must be at least partially unfolded to pass through the narrow needle-like channel (diameter <2 nm) of the T3SS. Fusion of effector proteins to tightly packed proteins—such as GFP, ubiquitin, or dihydrofolate reductase (DHFR)—impairs secretion and results in obstruction of the T3SS. Prior observation that unfolding can become rate-limiting for secretion has led to the model that T3SS effector proteins have low thermodynamic stability, facilitating their secretion. Here, we first show that the unfolding free energy (ΔGunfold0) of two Salmonella effector proteins, SptP and SopE2, are 6.9 and 6.0 kcal/mol, respectively, typical for globular proteins and similar to published ΔGunfold0 for GFP, ubiquitin, and DHFR. Next, we mechanically unfolded individual SptP and SopE2 molecules by atomic force microscopy (AFM)-based force spectroscopy. SptP and SopE2 unfolded at low force (Funfold ≤ 17 pN at 100 nm/s), making them among the most mechanically labile proteins studied to date by AFM. Moreover, their mechanical compliance is large, as measured by the distance to the transition state (Δx‡ = 1.6 and 1.5 nm for SptP and SopE2, respectively). In contrast, prior measurements of GFP, ubiquitin, and DHFR show them to be mechanically robust (Funfold > 80 pN) and brittle (Δx‡ < 0.4 nm). These results suggest that effector protein unfolding by T3SS is a mechanical process and that mechanical lability facilitates efficient effector protein secretion.

scholarly journals Essential Role of the SycP Chaperone in Type III Secretion of the YspP Effector

2008 ◽  
Vol 191 (5) ◽  
pp. 1703-1715 ◽  
Author(s):  
Hiroyuki Matsumoto ◽  
Glenn M. Young
Keyword(s):  
Amino Acids ◽  
Type Iii Secretion ◽  
Mammalian Cells ◽  
System Analysis ◽  
Tyrosine Phosphatase ◽  
Host Cells ◽  
Type Iii ◽  
System A ◽  
Minimal Region

ABSTRACT The Ysa type III secretion (T3S) system enhances gastrointestinal infection by Yersinia enterocolitica bv. 1B. One effector protein targeted into host cells is YspP, a protein tyrosine phosphatase. It was determined in this study that the secretion of YspP requires a chaperone, SycP. Genetic analysis showed that deletion of sycP completely abolished the secretion of YspP without affecting the secretion of other Ysps by the Ysa T3S system. Analysis of the secretion and translocation signals of YspP defined the first 73 amino acids to form the minimal region of YspP necessary to promote secretion and translocation by the Ysa T3S system. Function of the YspP secretion/translocation signals was dependent on SycP. Curiously, when YspP was constitutively expressed in Y. enterocolitica bv. 1B, it was recognized and secreted by the Ysc T3S system and the flagellar T3S system. In these cases, the first 21 amino acids were sufficient to promote secretion, and while SycP did enhance secretion, it was not essential. However, neither the Ysc T3S system nor the flagellar T3S system translocated YspP into mammalian cells. This supports a model where SycP confers secretion/translocation specificities for YspP by the Ysa T3S system. A series of biochemical approaches further established that SycP specifically interacts with YspP and protected YspP degradation in the cell prior to secretion. Collectively, the evidence suggests that YspP secretion by the Ysa T3S system is a posttranslational event.

scholarly journals Type III Secretion of the Salmonella Effector Protein SopE Is Mediated via an N-Terminal Amino Acid Signal and Not an mRNA Sequence

2005 ◽  
Vol 187 (5) ◽  
pp. 1559-1567 ◽  
Author(s):  
M. H. Karavolos ◽  
M. Wilson ◽  
J. Henderson ◽  
J. J. Lee ◽  
C. M. A. Khan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Host Cell ◽  
Type Iii Secretion ◽  
Effector Protein ◽  
Mrna Sequence ◽  
Type Iii ◽  
Amino Terminal ◽  
Terminal Amino

ABSTRACT Type III secretion systems (TTSS) are virulence-associated components of many gram-negative bacteria that translocate bacterial proteins directly from the bacterial cytoplasm into the host cell. The Salmonella translocated effector protein SopE has no consensus cleavable amino-terminal secretion sequence, and the mechanism leading to its secretion through the Salmonella pathogenicity island 1 (SPI-1) TTSS is still not fully understood. There is evidence from other bacteria which suggests that the TTSS signal may reside within the 5′ untranslated region (UTR) of the mRNA of secreted effectors. We investigated the role of the 5′ UTR in the SPI-1 TTSS-mediated secretion of SopE using promoter fusions and obtained data indicating that the mRNA sequence is not involved in the secretion process. To clarify the proteinaceous versus RNA nature of the signal, we constructed frameshift mutations in the amino-terminal region of SopE of Salmonella enterica serovar Typhimurium SL1344. Only constructs with the native amino acid sequence were secreted, highlighting the importance of the amino acid sequence versus the mRNA sequence for secretion. Additionally, we obtained frameshift mutation data suggesting that the first 15 amino acids are important for secretion of SopE independent of the presence of the chaperone binding site. These data shed light on the nature of the signal for SopE secretion and highlight the importance of the amino-terminal amino acids for correct targeting and secretion of SopE via the SPI-1-encoded TTSS during host cell invasion.

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