SsaV Interacts with SsaL to Control the Translocon-to-Effector Switch in the Salmonella SPI-2 Type Three Secretion System.


:Nonflagellar type III secretion systems (nf T3SSs) form a cell surface needle-like structure and an associated translocon that deliver bacterial effector proteins into eukaryotic host cells. This involves a tightly regulated hierarchy of protein secretion. A switch involving SctP and SctU stops secretion of the needle protein. The gatekeeper protein SctW is required for secretion of translocon proteins and controls a second switch to start effector secretion. Salmonella enterica serovar Typhimurium encodes two T3SSs in Salmonella pathogenicity island 1 (SPI-1) and SPI-2. The acidic vacuole containing intracellular bacteria stimulates assembly of the SPI-2 T3SS and its translocon. Sensing the nearly neutral host cytosolic pH is required for effector translocation. Here, we investigated the involvement of SPI-2-encoded proteins SsaP (SctP), SsaU (SctU), SsaV (SctV), and SsaL (SctW) in regulation of secretion. We found that SsaP and SsaU are involved in the first but not the second secretion switch. A random-mutagenesis screen identified amino acids of SsaV that regulate translocon and effector secretion. Single substitutions in subdomain 4 of SsaV or InvA (SPI-1-encoded SctV) phenocopied mutations of their corresponding gatekeepers with respect to translocon and effector protein secretion and host cell interactions. SsaL interacted with SsaV in bacteria exposed to low ambient pH but not after the pH was raised to 7.2. We propose that SsaP and SsaU enable the apparatus to become competent for a secretion switch and facilitate the SsaL-SsaV interaction. This mediates secretion of translocon proteins until neutral pH is sensed, which causes their dissociation, resulting in arrest of translocon secretion and derepression of effector translocation.IMPORTANCESalmonella Typhimurium is an intracellular pathogen that uses the SPI-2 type III secretion system to deliver virulence proteins across the vacuole membrane surrounding intracellular bacteria. This involves a tightly regulated hierarchy of protein secretion controlled by two molecular switches. We found that SPI-2-encoded proteins SsaP and SsaU are involved in the first but not the second secretion switch. We identify key amino acids of the inner membrane protein SsaV that are required to interact with the so-called gatekeeper protein SsaL and show that the dissociation of SsaV-SsaL causes the second switch, leading to delivery of effector proteins. Our results provide insights into the molecular events controlling virulence-associated type III secretion and suggest a broader model describing how the process is regulated.






Yu XJ,Grabe GJ,Liu M,Mota LJ,Holden DW




Has Abstract


2018-10-02 00:00:00












  • Bacteriophage Distributions and Temporal Variability in the Ocean's Interior.

    abstract::Bacteriophages are numerically the most abundant DNA-containing entities in the oligotrophic ocean, yet how specific phage populations vary over time and space remains to be fully explored. Here, we conducted a metagenomic time-series survey of double-stranded DNA phages throughout the water column in the North Pacifi...


    pub_type: 杂志文章


    authors: Luo E,Aylward FO,Mende DR,DeLong EF

    更新日期:2017-11-28 00:00:00

  • Proposal of a Taxonomic Nomenclature for the Bacillus cereus Group Which Reconciles Genomic Definitions of Bacterial Species with Clinical and Industrial Phenotypes.

    abstract::The Bacillus cereus group comprises numerous closely related species, including bioterrorism agent B. anthracis, foodborne pathogen B. cereus, and biopesticide B. thuringiensis Differentiating organisms capable of causing illness or death from those used in industry is essential for risk assessment and outbreak prepar...


    pub_type: 杂志文章


    authors: Carroll LM,Wiedmann M,Kovac J

    更新日期:2020-02-25 00:00:00

  • Novel Insights into Conformational Rearrangements of the Bacterial Flagellar Switch Complex.

    abstract::The flagellar motor can spin in both counterclockwise (CCW) and clockwise (CW) directions. The flagellar motor consists of a rotor and multiple stator units, which act as a proton channel. The rotor is composed of the transmembrane MS ring made of FliF and the cytoplasmic C ring consisting of FliG, FliM, and FliN. The...


    pub_type: 杂志文章


    authors: Sakai T,Miyata T,Terahara N,Mori K,Inoue Y,Morimoto YV,Kato T,Namba K,Minamino T

    更新日期:2019-04-02 00:00:00

  • Heteroresistance at the single-cell level: adapting to antibiotic stress through a population-based strategy and growth-controlled interphenotypic coordination.

    abstract:UNLABELLED:Heteroresistance refers to phenotypic heterogeneity of microbial clonal populations under antibiotic stress, and it has been thought to be an allocation of a subset of "resistant" cells for surviving in higher concentrations of antibiotic. The assumption fits the so-called bet-hedging strategy, where a bacte...


    pub_type: 杂志文章,多中心研究


    authors: Wang X,Kang Y,Luo C,Zhao T,Liu L,Jiang X,Fu R,An S,Chen J,Jiang N,Ren L,Wang Q,Baillie JK,Gao Z,Yu J

    更新日期:2014-02-11 00:00:00

  • Population Structure and Genetic Diversity among Isolates of Coccidioides posadasii in Venezuela and Surrounding Regions.

    abstract::Coccidioides posadasii is a pathogenic fungus that causes coccidioidomycosis in many arid regions of the Americas. One of these regions is bordered by the Caribbean Sea, and the surrounding landscape may play an important role in the dispersion of C. posadasii across South America through southeastern Mexico, Honduras...


    pub_type: 杂志文章


    authors: Teixeira MM,Alvarado P,Roe CC,Thompson GR 3rd,Patané JSL,Sahl JW,Keim P,Galgiani JN,Litvintseva AP,Matute DR,Barker BM

    更新日期:2019-11-26 00:00:00

  • Identification of a gamma interferon-activated inhibitor of translation-like RNA motif at the 3' end of the transmissible gastroenteritis coronavirus genome modulating innate immune response.

    abstract:UNLABELLED:A 32-nucleotide (nt) RNA motif located at the 3' end of the transmissible gastroenteritis coronavirus (TGEV) genome was found to specifically interact with the host proteins glutamyl-prolyl-tRNA synthetase (EPRS) and arginyl-tRNA synthetase (RRS). This RNA motif has high homology in sequence and secondary st...


    pub_type: 杂志文章


    authors: Marquez-Jurado S,Nogales A,Zuñiga S,Enjuanes L,Almazán F

    更新日期:2015-03-10 00:00:00

  • A Flexible Binding Site Architecture Provides New Insights into CcpA Global Regulation in Gram-Positive Bacteria.

    abstract::Catabolite control protein A (CcpA) is the master regulator in Gram-positive bacteria that mediates carbon catabolite repression (CCR) and carbon catabolite activation (CCA), two fundamental regulatory mechanisms that enable competitive advantages in carbon catabolism. It is generally regarded that CcpA exerts its reg...


    pub_type: 杂志文章


    authors: Yang Y,Zhang L,Huang H,Yang C,Yang S,Gu Y,Jiang W

    更新日期:2017-01-24 00:00:00

  • An association between peptidoglycan synthesis and organization of the Streptococcus pyogenes ExPortal.

    abstract:UNLABELLED:The ExPortal of Streptococcus pyogenes is a focal microdomain of the cytoplasmic membrane that clusters the translocons of the general secretory pathway with accessory factors to facilitate the maturation of secreted polypeptides. While it is known that the ExPortal is enriched in anionic lipids, the mechani...


    pub_type: 杂志文章


    authors: Vega LA,Port GC,Caparon MG

    更新日期:2013-09-24 00:00:00

  • Contribution of resistance-nodulation-cell division efflux systems to antibiotic resistance and biofilm formation in Acinetobacter baumannii.

    abstract:UNLABELLED:Acinetobacter baumannii is a nosocomial pathogen of increasing importance due to its multiple resistance to antibiotics and ability to survive in the hospital environment linked to its capacity to form biofilms. To fully characterize the contribution of AdeABC, AdeFGH, and AdeIJK resistance-nodulation-cell d...


    pub_type: 杂志文章


    authors: Yoon EJ,Chabane YN,Goussard S,Snesrud E,Courvalin P,Dé E,Grillot-Courvalin C

    更新日期:2015-03-24 00:00:00

  • Streptococcus pneumoniae is desiccation tolerant and infectious upon rehydration.

    abstract:UNLABELLED:Streptococcus pneumoniae (pneumococcus) is a frequent colonizer of the nasopharynx and one of the leading causative agents of otitis media, pneumonia, and meningitis. The current literature asserts that S. pneumoniae is transmitted person to person via respiratory droplets; however, environmental surfaces (f...


    pub_type: 杂志文章


    authors: Walsh RL,Camilli A

    更新日期:2011-05-24 00:00:00

  • Sex Steroids Induce Membrane Stress Responses and Virulence Properties in Pseudomonas aeruginosa.

    abstract::Estrogen, a major female sex steroid hormone, has been shown to promote the selection of mucoid Pseudomonas aeruginosa in the airways of patients with chronic respiratory diseases, including cystic fibrosis. This results in long-term persistence, poorer clinical outcomes, and limited therapeutic options. In this study...


    pub_type: 杂志文章


    authors: Vidaillac C,Yong VFL,Aschtgen MS,Qu J,Yang S,Xu G,Seng ZJ,Brown AC,Ali MK,Jaggi TK,Sankaran J,Foo YH,Righetti F,Nedumaran AM,Mac Aogáin M,Roizman D,Richard JA,Rogers TR,Toyofuku M,Luo D,Loh E,Wohland T,Czarny

    更新日期:2020-09-29 00:00:00

  • Improper Coordination of BamA and BamD Results in Bam Complex Jamming by a Lipoprotein Substrate.

    abstract::The β-barrel assembly machinery, the Bam complex, is central to the biogenesis of integral outer membrane proteins (OMPs) as well as OMP-dependent surface-exposed lipoproteins, such as regulator of capsule synthesis protein F (RcsF). Previous genetic analysis established the model that nonessential components BamE and...


    pub_type: 杂志文章


    authors: Tata M,Konovalova A

    更新日期:2019-05-21 00:00:00

  • Silver and Copper Acute Effects on Membrane Proteins and Impact on Photosynthetic and Respiratory Complexes in Bacteria.

    abstract::Silver (Ag+) and copper (Cu+) ions have been used for centuries in industry, as well as antimicrobial agents in agriculture and health care. Nowadays, Ag+ is also widely used in the field of nanotechnology. Yet, the underlying mechanisms driving toxicity of Ag+ ions in vivo are poorly characterized. It is well known t...


    pub_type: 杂志文章


    authors: Tambosi R,Liotenberg S,Bourbon ML,Steunou AS,Babot M,Durand A,Kebaili N,Ouchane S

    更新日期:2018-11-20 00:00:00

  • Novel Segment- and Host-Specific Patterns of Enteroaggregative Escherichia coli Adherence to Human Intestinal Enteroids.

    abstract::Enteroaggregative Escherichia coli (EAEC) is an important diarrheal pathogen and a cause of both acute and chronic diarrhea. It is a common cause of pediatric bacterial diarrhea in developing countries. Despite its discovery in 1987, the intestinal tropism of the pathogen remains unknown. Cell lines used to study EAEC...


    pub_type: 杂志文章


    authors: Rajan A,Vela L,Zeng XL,Yu X,Shroyer N,Blutt SE,Poole NM,Carlin LG,Nataro JP,Estes MK,Okhuysen PC,Maresso AW

    更新日期:2018-02-20 00:00:00

  • Biosynthesis of Conjugate Vaccines Using an O-Linked Glycosylation System.

    abstract:UNLABELLED:Conjugate vaccines are known to be one of the most effective and safest types of vaccines against bacterial pathogens. Previously, vaccine biosynthesis has been performed by using N-linked glycosylation systems. However, the structural specificity of these systems for sugar substrates has hindered their appl...


    pub_type: 杂志文章


    authors: Pan C,Sun P,Liu B,Liang H,Peng Z,Dong Y,Wang D,Liu X,Wang B,Zeng M,Wu J,Zhu L,Wang H

    更新日期:2016-04-26 00:00:00

  • Binding Heterogeneity of Plasmodium falciparum to Engineered 3D Brain Microvessels Is Mediated by EPCR and ICAM-1.

    abstract::Cerebral malaria is a severe neurological complication associated with sequestration of Plasmodium falciparum-infected erythrocytes (IE) in the brain microvasculature, but the specific binding interactions remain under debate. Here, we have generated an engineered three-dimensional (3D) human brain endothelial microve...


    pub_type: 杂志文章


    authors: Bernabeu M,Gunnarsson C,Vishnyakova M,Howard CC,Nagao RJ,Avril M,Taylor TE,Seydel KB,Zheng Y,Smith JD

    更新日期:2019-05-28 00:00:00

  • Nuclear Factor Y (NF-Y) Modulates Encystation in Entamoeba via Stage-Specific Expression of the NF-YB and NF-YC Subunits.

    abstract::Nuclear factor Y (NF-Y) is a heterotrimeric transcription factor composed of three subunits, namely, NF-YA, NF-YB, and NF-YC, which are conserved throughout evolution. In higher eukaryotes, NF-Y plays important roles in several cellular processes (development, cell cycle regulation, apoptosis, and response to growth, ...


    pub_type: 杂志文章


    authors: Manna D,Singh U

    更新日期:2019-06-18 00:00:00

  • Combinatorial Loss of the Enzymatic Activities of Viral Uracil-DNA Glycosylase and Viral dUTPase Impairs Murine Gammaherpesvirus Pathogenesis and Leads to Increased Recombination-Based Deletion in the Viral Genome.

    abstract::Misincorporation of uracil or spontaneous cytidine deamination is a common mutagenic insult to DNA. Herpesviruses encode a viral uracil-DNA glycosylase (vUNG) and a viral dUTPase (vDUT), each with enzymatic and nonenzymatic functions. However, the coordinated roles of these enzymatic activities in gammaherpesvirus pat...


    pub_type: 杂志文章


    authors: Dong Q,Smith KR,Oldenburg DG,Shapiro M,Schutt WR,Malik L,Plummer JB,Mu Y,MacCarthy T,White DW,McBride KM,Krug LT

    更新日期:2018-10-30 00:00:00

  • Antisense transcription is pervasive but rarely conserved in enteric bacteria.

    abstract::Noncoding RNAs, including antisense RNAs (asRNAs) that originate from the complementary strand of protein-coding genes, are involved in the regulation of gene expression in all domains of life. Recent application of deep-sequencing technologies has revealed that the transcription of asRNAs occurs genome-wide in bacter...


    pub_type: 杂志文章


    authors: Raghavan R,Sloan DB,Ochman H

    更新日期:2012-08-07 00:00:00

  • Ecosystem Resilience and Limitations Revealed by Soil Bacterial Community Dynamics in a Bark Beetle-Impacted Forest.

    abstract::Forested ecosystems throughout the world are experiencing increases in the incidence and magnitude of insect-induced tree mortality with large ecologic ramifications. Interestingly, correlations between water quality and the extent of tree mortality in Colorado montane ecosystems suggest compensatory effects from adja...


    pub_type: 杂志文章


    authors: Mikkelson KM,Brouillard BM,Bokman CM,Sharp JO

    更新日期:2017-12-05 00:00:00

  • Viral profiling identifies multiple subtypes of Kaposi's sarcoma.

    abstract:UNLABELLED:Kaposi's sarcoma (KS), caused by KS-associated herpesvirus (KSHV), is the most common cancer among HIV-infected patients in Malawi and in the United States today. In Malawi, KSHV is endemic. We conducted a cross-sectional study of patients with HIV infection and KS with no history of chemo- or antiretroviral...


    pub_type: 杂志文章


    authors: Hosseinipour MC,Sweet KM,Xiong J,Namarika D,Mwafongo A,Nyirenda M,Chiwoko L,Kamwendo D,Hoffman I,Lee J,Phiri S,Vahrson W,Damania B,Dittmer DP

    更新日期:2014-09-23 00:00:00

  • Viral Diversity of House Mice in New York City.

    abstract::The microbiome of wild Mus musculus (house mouse), a globally distributed invasive pest that resides in close contact with humans in urban centers, is largely unexplored. Here, we report analysis of the fecal virome of house mice in residential buildings in New York City, NY. Mice were collected at seven sites in Manh...


    pub_type: 杂志文章


    authors: Williams SH,Che X,Garcia JA,Klena JD,Lee B,Muller D,Ulrich W,Corrigan RM,Nichol S,Jain K,Lipkin WI

    更新日期:2018-04-17 00:00:00

  • A Stress-Induced Bias in the Reading of the Genetic Code in Escherichia coli.

    abstract::Escherichia coli mazEF is an extensively studied stress-induced toxin-antitoxin (TA) system. The toxin MazF is an endoribonuclease that cleaves RNAs at ACA sites. Thereby, under stress, the induced MazF generates a stress-induced translation machinery (STM), composed of MazF-processed mRNAs and selective ribosomes tha...


    pub_type: 杂志文章


    authors: Oron-Gottesman A,Sauert M,Moll I,Engelberg-Kulka H

    更新日期:2016-11-15 00:00:00

  • Minimal Elements Required for the Formation of Respiratory Syncytial Virus Cytoplasmic Inclusion Bodies In Vivo and In Vitro.

    abstract::Infection of host cells by the respiratory syncytial virus (RSV) is characterized by the formation of spherical cytoplasmic inclusion bodies (IBs). These structures, which concentrate all the proteins of the polymerase complex as well as some cellular proteins, were initially considered aggresomes formed by viral dead...


    pub_type: 杂志文章


    authors: Galloux M,Risso-Ballester J,Richard CA,Fix J,Rameix-Welti MA,Eléouët JF

    更新日期:2020-09-22 00:00:00

  • Proteomics Analysis Reveals Previously Uncharacterized Virulence Factors in Vibrio proteolyticus.

    abstract:UNLABELLED:Members of the genus Vibrio include many pathogens of humans and marine animals that share genetic information via horizontal gene transfer. Hence, the Vibrio pan-genome carries the potential to establish new pathogenic strains by sharing virulence determinants, many of which have yet to be characterized. He...


    pub_type: 杂志文章


    authors: Ray A,Kinch LN,de Souza Santos M,Grishin NV,Orth K,Salomon D

    更新日期:2016-07-26 00:00:00

  • Cytokeratin 8 is an epithelial cell receptor for Pet, a cytotoxic serine protease autotransporter of Enterobacteriaceae.

    abstract:UNLABELLED:The group of proteins known as serine protease autotransporters of Enterobacteriaceae (SPATE) is a growing family of serine proteases secreted to the external milieu by the type V secretion system. Pet toxin and some other SPATE belong to the class 1 cytotoxic SPATE, which have comparable protease strength o...


    pub_type: 杂志文章


    authors: Nava-Acosta R,Navarro-Garcia F

    更新日期:2013-12-10 00:00:00

  • Coagulase and Efb of Staphylococcus aureus Have a Common Fibrinogen Binding Motif.

    abstract:UNLABELLED:Coagulase (Coa) and Efb, secreted Staphylococcus aureus proteins, are important virulence factors in staphylococcal infections. Coa interacts with fibrinogen (Fg) and induces the formation of fibrin(ogen) clots through activation of prothrombin. Efb attracts Fg to the bacterial surface and forms a shield to ...


    pub_type: 杂志文章


    authors: Ko YP,Kang M,Ganesh VK,Ravirajan D,Li B,Höök M

    更新日期:2016-01-05 00:00:00

  • BiP and multiple DNAJ molecular chaperones in the endoplasmic reticulum are required for efficient simian virus 40 infection.

    abstract::Simian virus 40 (SV40) is a nonenveloped DNA virus that traffics through the endoplasmic reticulum (ER) en route to the nucleus, but the mechanisms of capsid disassembly and ER exit are poorly understood. We conducted an unbiased RNA interference screen to identify cellular genes required for SV40 infection. SV40 infe...


    pub_type: 杂志文章


    authors: Goodwin EC,Lipovsky A,Inoue T,Magaldi TG,Edwards AP,Van Goor KE,Paton AW,Paton JC,Atwood WJ,Tsai B,DiMaio D

    更新日期:2011-06-14 00:00:00

  • Middle East Respiratory Syndrome Coronavirus NS4b Protein Inhibits Host RNase L Activation.

    abstract:UNLABELLED:Middle East respiratory syndrome coronavirus (MERS-CoV) is the first highly pathogenic human coronavirus to emerge since severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002. Like many coronaviruses, MERS-CoV carries genes that encode multiple accessory proteins that are not required for replicat...


    pub_type: 杂志文章


    authors: Thornbrough JM,Jha BK,Yount B,Goldstein SA,Li Y,Elliott R,Sims AC,Baric RS,Silverman RH,Weiss SR

    更新日期:2016-03-29 00:00:00

  • Integration of the second messenger c-di-GMP into the chemotactic signaling pathway.

    abstract:UNLABELLED:Elevated intracellular levels of the bacterial second messenger c-di-GMP are known to suppress motility and promote sessility. Bacterial chemotaxis guides motile cells in gradients of attractants and repellents over broad concentration ranges, thus allowing bacteria to quickly adapt to changes in their surro...


    pub_type: 杂志文章


    authors: Russell MH,Bible AN,Fang X,Gooding JR,Campagna SR,Gomelsky M,Alexandre G

    更新日期:2013-03-19 00:00:00