scholarly journals A multi-pronged search for a common structural motif in the secretion signal of Salmonella enterica serovar Typhimurium type III effector proteins

2010 ◽  
Vol 6 (12) ◽  
pp. 2448 ◽  
Author(s):  
Garry W. Buchko ◽  
George Niemann ◽  
Erin S. Baker ◽  
Mikhail E. Belov ◽  
Richard D. Smith ◽  
...  
2007 ◽  
Vol 51 (8) ◽  
pp. 2867-2876 ◽  
Author(s):  
Aurel Negrea ◽  
Eva Bjur ◽  
Sofia Eriksson Ygberg ◽  
Mikael Elofsson ◽  
Hans Wolf-Watz ◽  
...  

ABSTRACT A collection of nine salicylidene acylhydrazide compounds were tested for their ability to inhibit the activity of virulence-associated type III secretion systems (T3SSs) in Salmonella enterica serovar Typhimurium. The compounds strongly affected Salmonella pathogenicity island 1 (SPI1) T3SS-mediated invasion of epithelial cells and in vitro secretion of SPI1 invasion-associated effector proteins. The use of a SPI1 effector β-lactamase fusion protein implicated intracellular entrapment of the protein construct upon application of a salicylidene acylhydrazide, whereas the use of chromosomal transcriptional gene fusions revealed a compound-mediated transcriptional silencing of SPI1. Salicylidene acylhydrazides also affected intracellular bacterial replication in murine macrophage-like cells and blocked the transport of an epitope-tagged SPI2 effector protein. Two of the compounds significantly inhibited bacterial motility and expression of extracellular flagellin. We conclude that salicylidene acylhydrazides affect bacterial T3SS activity in S. enterica and hence could be used as lead substances when designing specific inhibitors of bacterial T3SSs in order to pharmaceutically intervene with bacterial virulence.


Vaccine ◽  
2006 ◽  
Vol 24 (37-39) ◽  
pp. 6216-6224 ◽  
Author(s):  
Camille N. Kotton ◽  
Alexander J. Lankowski ◽  
Nathaniel Scott ◽  
David Sisul ◽  
Li Mei Chen ◽  
...  

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1805-1814 ◽  
Author(s):  
R. Boonyom ◽  
M. H. Karavolos ◽  
D. M. Bulmer ◽  
C. M. A. Khan

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important pathogen and a causative agent of gastroenteritis. During infection, S. Typhimurium assembles molecular-needle complexes termed type III secretion (T3S) systems to translocate effector proteins from the bacterial cytoplasm directly into the host cell. The T3S signals that direct the secretion of effectors still remain enigmatic. SopD is a key T3S effector contributing to the systemic virulence of S. Typhimurium and the development of gastroenteritis. We have scrutinized the distribution of the SopD T3S signals using in silico analysis and a targeted deletion approach. We show that amino acid residues 6–10 act as the N-terminal secretion signal for Salmonella pathogenicity island 1 (SPI-1) T3S. Furthermore, we show that two putative C-terminal helical regions of SopD are essential for its secretion and also help prevent erroneous secretion through the flagellar T3S machinery. In addition, using protein–protein interaction assays, we have identified an association between SopD and the SPI-1 T3S system ATPase, InvC. These findings demonstrate that T3S of SopD involves multiple signals and protein interactions, providing important mechanistic insights into effector protein secretion.


Microbiology ◽  
2007 ◽  
Vol 153 (4) ◽  
pp. 1221-1228 ◽  
Author(s):  
M. N Giacomodonato ◽  
S Uzzau ◽  
D Bacciu ◽  
R Caccuri ◽  
S. H Sarnacki ◽  
...  

2013 ◽  
Vol 57 (5) ◽  
pp. 2191-2198 ◽  
Author(s):  
Jianfang Li ◽  
Chao Lv ◽  
Weiyang Sun ◽  
Zhenyu Li ◽  
Xiaowei Han ◽  
...  

ABSTRACTBacterial virulence factors have been increasingly regarded as attractive targets for development of novel antibacterial agents. Virulence inhibitors are less likely to generate bacterial resistance, which makes them superior to traditional antibiotics that target bacterial viability.Salmonella entericaserovar Typhimurium, an important food-borne human pathogen, has type III secretion system (T3SS) as its major virulence factor. T3SS secretes effector proteins to facilitate invasion into host cells. In this study, we identified several analogs of cytosporone B (Csn-B) that strongly block the secretion ofSalmonellapathogenicity island 1 (SPI-1)-associated effector proteins, without affecting the secretion of flagellar protein FliCin vitro. Csn-B and two other derivatives exhibited a strong inhibitory effect on SPI-1-mediated invasion to HeLa cells, while no significant toxicity to bacteria was observed. Nucleoid proteins Hha and H-NS bind to the promoters of SPI-1 regulator geneshilD,hilC, andrtsAto repress their expression and consequently regulate the expression of SPI-1 apparatus and effector genes. We found that Csn-B upregulated the transcription ofhhaandhns, implying that Csn-B probably affected the secretion of effectors through the Hha–H-NS regulatory pathway. In summary, this study presented an effective SPI-1 inhibitor, Csn-B, which may have potential in drug development against antibiotic-resistantSalmonella.


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