scholarly journals Beyond Slam: the DUF560 family outer membrane protein superfamily SPAM has distinct network subclusters that suggest a role in non-lipidated substrate transport and bacterial environmental adaptation

2020 ◽  
Author(s):  
Terra J. Mauer ◽  
Alex S. Grossman ◽  
Katrina T. Forest ◽  
Heidi Goodrich-Blair
Keyword(s):  
Host Range ◽  
Outer Membrane ◽  
Binding Protein ◽  
Sequence Similarity ◽  
Outer Membrane Proteins ◽  
Environmental Adaptation ◽  
Host Cells ◽  
Xenorhabdus Nematophila ◽  
Associated Bacteria ◽  
Host Phylogeny

AbstractIn host-associated bacteria, surface and secreted proteins mediate acquisition of nutrients, interactions with host cells, and specificity of host-range and tissue-localization. In Gram-negative bacteria, the mechanism by which many proteins cross, become embedded within, or become tethered to the outer membrane remains unclear. The domain of unknown function (DUF)560 occurs in outer membrane proteins found throughout and beyond the proteobacteria. Functionally characterized DUF560 representatives include NilB, a host-range specificity determinant of the nematode-mutualist Xenorhabdus nematophila and the surface lipoprotein assembly modulators (Slam), Slam1 and Slam2 which facilitate surface exposure of lipoproteins in the human pathogen Neisseria meningitidis. Through network analysis of protein sequence similarity we show that DUF560 subclusters exist and correspond with organism lifestyle rather than with taxonomy, suggesting a role for these proteins in environmental adaptation. Cluster 1 had the greatest number of representative proteins, was dominated by homologs from animal-associated symbionts, and was composed of subclusters: 1A (containing NilB, Slam1, and Slam2), 1B, and 1C. Genome neighborhood networks revealed that Cluster 1A DUF560 members are strongly associated with TonB, TonB-dependent receptors, and predicted co-receptors such as the Slam1 lipoprotein substrates transferrin binding protein and lactoferrin binding protein. The genome neighborhood network of Cluster 1B sequences are similarly dominated by TonB loci, but typically the associated co-receptors (the presumed DUF560 substrates) are predicted to be non-lipidated. We suggest that these subclusters within the DUF560 protein family indicate distinctive activities and that Slam activity may be characteristic of Cluster 1A members but not all DUF560 homologs. For Cluster 1 DUF560 homologs we propose the name SPAM (Surface/Secreted Protein Associated Outer Membrane Proteins) to accommodate the potential for non-lipoprotein substrates or different activities. We show that the repertoire of SPAM proteins in Xenorhabdus correlates with host phylogeny, suggesting that the host environment drives the evolution of these symbiont-encoded proteins. This pattern of selection for specific sequences based on host physiology and/or environmental factors may extend to other clusters of the DUF560 family.

scholarly journals Correction: Fine Mapping of the Interaction between C4b-Binding Protein and Outer Membrane Proteins LigA and LigB of Pathogenic Leptospira interrogans

2015 ◽  
Vol 9 (12) ◽  
pp. e0004286 ◽  
Author(s):  
Leandro C. D. Breda ◽  
Ching-Lin Hsieh ◽  
Mónica M. Castiblanco Valencia ◽  
Ludmila B. da Silva ◽  
Angela S. Barbosa ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Fine Mapping ◽  
Binding Protein ◽  
Outer Membrane Proteins ◽  
Leptospira Interrogans ◽  
Pathogenic Leptospira

scholarly journals Fine Mapping of the Interaction between C4b-Binding Protein and Outer Membrane Proteins LigA and LigB of Pathogenic Leptospira interrogans

2015 ◽  
Vol 9 (10) ◽  
pp. e0004192 ◽  
Author(s):  
Leandro C. D. Breda ◽  
Ching-Lin Hsieh ◽  
Mónica M. Castiblanco Valencia ◽  
Ludmila B. da Silva ◽  
Angela S. Barbosa ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Fine Mapping ◽  
Binding Protein ◽  
Outer Membrane Proteins ◽  
Leptospira Interrogans ◽  
Pathogenic Leptospira

scholarly journals Cag3 Is a Novel Essential Component of the Helicobacter pylori Cag Type IV Secretion System Outer Membrane Subcomplex

2009 ◽  
Vol 191 (23) ◽  
pp. 7343-7352 ◽  
Author(s):  
Delia M. Pinto-Santini ◽  
Nina R. Salama
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Protein Interactions ◽  
Sequence Similarity ◽  
Structural Similarity ◽  
Type Iv Secretion ◽  
Host Cells ◽  
Gastric Disease ◽  
Type Iv ◽  
Steady State Levels

ABSTRACT Helicobacter pylori strains harboring the cag pathogenicity island (PAI) have been associated with more severe gastric disease in infected humans. The cag PAI encodes a type IV secretion (T4S) system required for CagA translocation into host cells as well as induction of proinflammatory cytokines, such as interleukin-8 (IL-8). cag PAI genes sharing sequence similarity with T4S components from other bacteria are essential for Cag T4S function. Other cag PAI-encoded genes are also essential for Cag T4S, but lack of sequence-based or structural similarity with genes in existing databases has precluded a functional assignment for the encoded proteins. We have studied the role of one such protein, Cag3 (HP0522), in Cag T4S and determined Cag3 subcellular localization and protein interactions. Cag3 is membrane associated and copurifies with predicted inner and outer membrane Cag T4S components that are essential for Cag T4S as well as putative accessory factors. Coimmunoprecipitation and cross-linking experiments revealed specific interactions with HpVirB7 and CagM, suggesting Cag3 is a new component of the Cag T4S outer membrane subcomplex. Finally, lack of Cag3 lowers HpVirB7 steady-state levels, further indicating Cag3 makes a subcomplex with this protein.

scholarly journals Physical Linkage of Naturally Complexed Bacterial Outer Membrane Proteins Enhances Immunogenicity

2007 ◽  
Vol 76 (3) ◽  
pp. 1223-1229 ◽  
Author(s):  
Henriette Macmillan ◽  
Junzo Norimine ◽  
Kelly A. Brayton ◽  
Guy H. Palmer ◽  
Wendy C. Brown
Keyword(s):  
T Cell ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Surface Protein ◽  
Host Cells ◽  
Effective Vaccine ◽  
T Cell Epitopes ◽  
Carrier Effect ◽  
Major Surface

ABSTRACTThe outer membrane proteins (OMPs) of bacterial pathogens are essential for their growth and survival and especially for attachment and invasion of host cells. Since the outer membrane is the interface between the bacterium and the host cell, outer membranes and individual OMPs are targeted for development of vaccines against many bacterial diseases. Whole outer membrane fractions often protect against disease, and this protection cannot be fully reproduced by using individual OMPs. Exactly how the interactions among individual OMPs influence immunity is not well understood. We hypothesized that one OMP rich in T-cell epitopes can act as a carrier for an associated OMP which is poor in T-cell epitopes to generate T-dependent antibody responses, similar to the hapten-carrier effect. Major surface protein 1a (MSP1a) and MSP1b1 occur as naturally complexed OMPs in theAnaplasma marginaleouter membrane. Previous studies demonstrated that immunization with the native MSP1 heteromer induced strong immunoglobulin G (IgG) responses to both proteins, but only MSP1a stimulated strong CD4+T-cell responses. Therefore, to test our hypothesis, constructs of CD4+T-cell epitopes from MSP1a linked to MSP1b1 were compared with individually administered MSP1a and MSP1b1 for induction of MSP1b-specific IgG. By linking the T-cell epitopes from MSP1a to MSP1b1, significantly higher IgG titers against MSP1b1 were induced. Understanding how the naturally occurring intermolecular interactions between OMPs influence the immune response may lead to more effective vaccine design.

scholarly journals How the colonic environment influences Enterohaemorrhagic E. coli outer membrane vesicle production, and the interaction between outer membrane vesicles with human host cells

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Daniel Yara ◽  
Regis Stentz ◽  
Tom Wileman ◽  
Stephanie Schuller
Keyword(s):  
Outer Membrane ◽  
Bile Salts ◽  
Membrane Vesicle ◽  
Outer Membrane Proteins ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
T84 Cells ◽  
E Coli

Enterohaemorrhagic E. coli (EHEC) may instigate bloody diarrhoea and haemolytic uraemic syndrome (HUS) due to Shiga toxin (Stx) production. Stx has been detected within outer membrane vesicles (OMVs), which are membrane-derived nanosized proteoliposomes. During colonisation, EHEC encounters many environmental surroundings such as the presence of bile salts and carbon dioxide (CO2). Here, the influence of different intestinal cues on EHEC OMV production was studied. OMV yield was quantified by densitometric analysis of outer membrane proteins F/C and A, following OMV protein separation by SDS-PAGE. Compared to cultures in Luria broth, higher OMV yields were attained following culture in human cell growth medium and simulated colonic environmental medium, with further increases in the presence of bile salts. Interestingly, lower yields were attained in the presence of T84 cells and CO2. The interaction between OMVs and different human cells was also examined by fluorescence microscopy. Here, OMVs incubated with cells showed internalisation by semi confluent but not fully confluent T84 cell monolayers. OMVs were internalised into the lysosomes in confluent Vero and Caco-2 cells, with Stx being transported to the Golgi and then the Endoplasmic reticulum. OMVs were detected within polarised Caco-2 cells, with no impact on the transepithelial electrical resistance by 24 hours. These results suggest that the colonic environmental factors influences OMV production in vivo. Additionally, results highlight the discrepancies which arise when using different cells lines to examine the intestine. Nevertheless, coupled with Stx, OMVs may serve as tools of EHEC which are involved in HUS development.

scholarly journals The Landscape of Pseudomonas aeruginosa Membrane-Associated Proteins

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2421
Author(s):  
Sara Motta ◽  
Davide Vecchietti ◽  
Alessandra M. Martorana ◽  
Pietro Brunetti ◽  
Giovanni Bertoni ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Protein Identification ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Protein Domains ◽  
Host Cells ◽  
Inner Membrane ◽  
Proteomic Data ◽  
Associated Proteins

Background: Pseudomonas aeruginosa cell envelope-associated proteins play a relevant role in infection mechanisms. They can contribute to the antibiotic resistance of the bacterial cells and be involved in the interaction with host cells. Thus, studies contributing to elucidating these key molecular elements are of great importance to find alternative therapeutics. Methods: Proteins and peptides were extracted by different methods and analyzed by Multidimensional Protein Identification Technology (MudPIT) approach. Proteomic data were processed by Discoverer2.1 software and multivariate statistics, i.e., Linear Discriminant Analysis (LDA), while the Immune Epitope Database (IEDB) resources were used to predict antigenicity and immunogenicity of experimental identified peptides and proteins. Results: The combination of 29 MudPIT runs allowed the identification of 10,611 peptides and 2539 distinct proteins. Following application of extraction methods enriching specific protein domains, about 15% of total identified peptides were classified in trans inner-membrane, inner-membrane exposed, trans outer-membrane and outer-membrane exposed. In this scenario, nine outer membrane proteins (OprE, OprI, OprF, OprD, PagL, OprG, PA1053, PAL and PA0833) were predicted to be highly antigenic. Thus, they were further processed and epitopes target of T cells (MHC Class I and Class II) and B cells were predicted. Conclusion: The present study represents one of the widest characterizations of the P. aeruginosa membrane-associated proteome. The feasibility of our method may facilitates the investigation of other bacterial species whose envelope exposed protein domains are still unknown. Besides, the stepwise prioritization of proteome, by combining experimental proteomic data and reverse vaccinology, may be useful for reducing the number of proteins to be tested in vaccine development.

scholarly journals Mutagenesis and Functional Reconstitution of Chlamydial Major Outer Membrane Proteins: VS4 Domains Are Not Required for Pore Formation but Modify Channel Function

2001 ◽  
Vol 69 (3) ◽  
pp. 1671-1678 ◽  
Author(s):  
E. S. Hughes ◽  
K. M. Shaw ◽  
R. H. Ashley
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Single Channel ◽  
Outer Membrane Proteins ◽  
Host Cells ◽  
Chimeric Proteins ◽  
Functional Differences ◽  
And Function ◽  
Bacterial Porins ◽  
Medical Interest

ABSTRACT Chlamidial organisms are obligate intracellular pathogens containing highly antigenic porin-like major outer membrane proteins (MOMPs). MOMP epitopes are of substantial medical interest, and they cluster within four relatively short variable (VS) domains. If MOMPs adopt a β-barrel fold, like bacterial porins, the VS domains may form extramembranous loops and the conserved regions of the protein may correspond to predicted membrane-located β-strands. However, molecular studies on native MOMPs have been hampered by the need to culture chlamydiae in eukaryotic host cells and purification and reconstitution remain problematic. In addition, the organisms are difficult to manipulate genetically, and it has also been difficult to functionally reconstitute recombinant MOMPs. To help overcome these problems and improve our understanding of MOMP structure and function, we cloned and expressed C. trachomatis and C. psittaci MOMPs and functionally reconstituted them at the single-channel level. We measured significant functional differences between the two proteins, and by removing and exchanging VS4, we tested the hypothesis that the largest variable domain forms an extramembranous loop that contributes to these differences. Proteins in which VS4 was deleted continued to form functional ion channels, consistent with the idea that the domain forms an extramembranous protein loop and incompatible with models in which it contributes to predicted membrane-located β-strands. Additionally, the properties of the chimeric proteins strongly suggested that the VS4 domain interacts closely with other regions of the protein to form the channel entrance or vestibule. Our approach can be used to probe structure-function relationships in chlamydial MOMPs and may have implications for the generation of effective antichlamydial vaccines.

scholarly journals Lack of Outer Membrane Protein A Enhances the Release of Outer Membrane Vesicles and Survival ofVibrio choleraeand Suppresses Viability ofAcanthamoeba castellanii

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Soni Priya Valeru ◽  
Salah Shanan ◽  
Haifa Alossimi ◽  
Amir Saeed ◽  
Gunnar Sandström ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Wild Type ◽  
Outer Membrane Protein A

Vibrio cholerae, the causative agent of the diarrhoeal disease cholera, survives in aquatic environments. The bacterium has developed a survival strategy to grow and survive insideAcanthamoeba castellanii. It has been shown thatV. choleraeexpresses outer membrane proteins as virulence factors playing a role in the adherence to interacted host cells. This study examined the role of outer membrane protein A (OmpA) and outer membrane vesicles (OMVs) in survival ofV. choleraealone and during its interaction withA. castellanii. The results showed that anOmpAmutant ofV. choleraesurvived longer than wild-typeV. choleraewhen cultivated alone. Cocultivation withA. castellaniienhanced the survival of both bacterial strains andOmpAprotein exhibited no effect on attachment, engulfment, and survival inside the amoebae. However, cocultivation of theOmpAmutant ofV. choleraedecreased the viability ofA. castellaniiand this bacterial strain released more OMVs than wild-typeV. cholerae. Surprisingly, treatment of amoeba cells with OMVs isolated from theOmpAmutant significantly decreased viable counts of the amoeba cells. In conclusion, the results might highlight a regulating rule forOmpAin survival ofV. choleraeand OMVs as a potent virulence factor for this bacterium towards eukaryotes in the environment.

scholarly journals MID and UspA1/A2 of the human respiratory pathogen Moraxella catarrhalis, and interactions with the human host as basis for vaccine development.

2006 ◽  
Vol 53 (3) ◽  
pp. 445-456 ◽  
Author(s):  
Kristian Riesbeck ◽  
Thuan Tong Tan ◽  
Arne Forsgren
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Moraxella Catarrhalis ◽  
Vaccine Development ◽  
Binding Protein ◽  
Outer Membrane Proteins ◽  
Respiratory Pathogen ◽  
Transcriptional Level ◽  
Classical Pathway ◽  
Human Host

Moraxella catarrhalis IgD-binding protein MID is a 200 kDa autotransporter protein that exists as a oligomer and is governed at the transcriptional level. The majority of M. catarrhalis clinical isolates expresses MID. Two functional domains have been attributed to MID; MID764-913 functions as an adhesin and promotes the bacteria to attach to epithelial cells, whereas the IgD-binding domain is located within MID962-1200. In parallel, MID is stimulatory for B lymphocytes through the IgD B cell receptor. M. catarrhalis ubiquitous surface proteins A1 and A2 (UspA1/A2) are multifunctional outer membrane proteins that can bind complement and extracellular matrix proteins such as vitronectin and fibronectin. An interaction between the complement fluid phase regulator of the classical pathway, C4b binding protein (C4BP), and UspA1/A2 has also been observed. Moreover, UspA1/A2 has a unique feature to interfere with the innate immune system of complement by binding C3. Taken together, a growing body of knowledge on M. catarrhalis outer membrane proteins MID and UspA1/A2 and their precise interactions with the human host make them promising vaccine candidates in a future multicomponent vaccine.

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