scholarly journals Discovery of fibrillar adhesins across bacterial species

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Vivian Monzon ◽  
Aleix Lafita ◽  
Alex Bateman

Abstract Background Fibrillar adhesins are long multidomain proteins that form filamentous structures at the cell surface of bacteria. They are an important yet understudied class of proteins composed of adhesive and stalk domains that mediate interactions of bacteria with their environment. This study aims to characterize fibrillar adhesins in a wide range of bacterial phyla and to identify new fibrillar adhesin-like proteins to improve our understanding of host-bacteria interactions. Results Through careful literature and computational searches, we identified 82 stalk and 27 adhesive domain families in fibrillar adhesins. Based on the presence of these domains in the UniProt Reference Proteomes database, we identified and analysed 3,542 fibrillar adhesin-like proteins across species of the most common bacterial phyla. We further enumerate the adhesive and stalk domain combinations found in nature and demonstrate that fibrillar adhesins have complex and variable domain architectures, which differ across species. By analysing the domain architecture of fibrillar adhesins, we show that in Gram positive bacteria, adhesive domains are mostly positioned at the N-terminus and cell surface anchors at the C-terminus of the protein, while their positions are more variable in Gram negative bacteria. We provide an open repository of fibrillar adhesin-like proteins and domains to enable further studies of this class of bacterial surface proteins. Conclusion This study provides a domain-based characterization of fibrillar adhesins and demonstrates that they are widely found in species across the main bacterial phyla. We have discovered numerous novel fibrillar adhesins and improved our understanding of pathogenic adhesion and invasion mechanisms.

2020 ◽  
Author(s):  
Vivian Monzon ◽  
Aleix Lafita ◽  
Alex Bateman

AbstractBackgroundFibrillar adhesins are long multidomain proteins attached at the cell surface and composed of at least one adhesive domain and multiple tandemly repeated domains, which build an elongated stalk that projects the adhesive domain beyond the bacterial cell surface. They are an important yet understudied class of proteins that mediate interactions of bacteria with their environment. This study aims to characterize fibrillar adhesins in a wide range of bacterial phyla and to identify new fibrillar adhesin-like proteins to improve our understanding of host-bacteria interactions.ResultsBy careful search for fibrillar adhesins in the literature and by computational analysis we identified 75 stalk domains and 24 adhesive domains. Based on the presence of these domains in the UniProt Reference Proteomes database, we identified and analysed 3,388 fibrillar adhesin-like proteins across species of the most common bacterial phyla. We found that the bacterial proteomes with the highest fraction of fibrillar adhesins include several known pathogens. We further enumerate the adhesive and stalk domain combinations found in nature and demonstrate that fibrillar adhesins have complex and variable domain architectures, which differ across species. By analysing the domain architecture of fibrillar adhesins we show that in Gram positive bacteria adhesive domains are mostly positioned at the N-terminus of the protein with the cell surface anchor at the C-terminus, while their positions are more variable in Gram negative bacteria. We provide an open repository of fibrillar adhesin-like proteins and domains to facilitate downstream studies of this class of bacterial surface proteins.ConclusionThis study provides a domain-based characterization of fibrillar adhesins and demonstrates that they are widely found across the main bacterial phyla. We have discovered numerous novel fibrillar adhesins and improved the understanding of how pathogens might adhere to and subsequently invade into host cells.


2021 ◽  
Vol 12 ◽  
Author(s):  
Lei Sun ◽  
Gil Rogiers ◽  
Pascal Courtin ◽  
Marie-Pierre Chapot-Chartier ◽  
Hélène Bierne ◽  
...  

A mutant of Listeria monocytogenes ScottA with a transposon in the 5' untranslated region of the asnB gene was identified to be hypersensitive to the antimicrobial t-cinnamaldehyde. Here, we report the functional characterization of AsnB in peptidoglycan (PG) modification and intracellular infection. While AsnB of Listeria is annotated as a glutamine-dependent asparagine synthase, sequence alignment showed that this protein is closely related to a subset of homologs that catalyze the amidation of meso-diaminopimelic acid (mDAP) residues in the peptidoglycan of other bacterial species. Structural analysis of peptidoglycan from an asnB mutant, compared to that of isogenic wild-type (WT) and complemented mutant strains, confirmed that AsnB mediates mDAP amidation in L. monocytogenes. Deficiency in mDAP amidation caused several peptidoglycan- and cell surface-related phenotypes in the asnB mutant, including formation of shorter but thicker cells, susceptibility to lysozyme, loss of flagellation and motility, and a strong reduction in biofilm formation. In addition, the mutant showed reduced invasion of human epithelial JEG-3 and Caco-2 cells. Analysis by immunofluorescence microscopy revealed that asnB inactivation abrogated the proper display at the listerial surface of the invasion protein InlA, which normally gets cross-linked to mDAP via its LPXTG motif. Together, this work shows that AsnB of L. monocytogenes, like several of its homologs in related Gram-positive bacteria, mediates the amidation of mDAP residues in the peptidoglycan and, in this way, affects several cell wall and cell surface-related properties. It also for the first time implicates the amidation of peptidoglycan mDAP residues in cell wall anchoring of InlA and in bacterial virulence.


2007 ◽  
Vol 98 (09) ◽  
pp. 488-496 ◽  
Author(s):  
Patric Nitsche-Schmitz ◽  
Manfred Rohde ◽  
Gursharan Chhatwal

SummaryGram-positive cocci are important human pathogens. Streptococci and staphylococci in particular are a major threat to human health,since they cause a variety of serious invasive infections. Their invasion into normally sterile sites of the host depends on elaborated bacterial mechanisms that involve adhesion to the host tissue, its degradation, internalisation by host cells, and passage through epithelia and endothelia. Interactions of bacterial surface proteins with proteins of the host’s extracellular matrix as well as with cell surface receptors are crucial factors in these processes, and some of the key mechanisms are similar in many pathogenic Gram-positive cocci.Therapies that interfere with these mechanisms may become efficient alternatives to today’s antibiotic treatments.


2016 ◽  
Vol 44 (6) ◽  
pp. 1659-1666 ◽  
Author(s):  
Kurt H. Piepenbrink ◽  
Eric J. Sundberg

Type IV pili are hair-like bacterial surface appendages that play a role in diverse processes such as cellular adhesion, colonization, twitching motility, biofilm formation, and horizontal gene transfer. These extracellular fibers are composed exclusively or primarily of many copies of one or more pilin proteins, tightly packed in a helix so that the highly hydrophobic amino-terminus of the pilin is buried in the pilus core. Type IV pili have been characterized extensively in Gram-negative bacteria, and recent advances in high-throughput genomic sequencing have revealed that they are also widespread in Gram-positive bacteria. Here, we review the current state of knowledge of type IV pilus systems in Gram-positive bacterial species and discuss them in the broader context of eubacterial type IV pili.


2010 ◽  
Vol 76 (23) ◽  
pp. 7881-7884 ◽  
Author(s):  
Shana Topp ◽  
Colleen M. K. Reynoso ◽  
Jessica C. Seeliger ◽  
Ian S. Goldlust ◽  
Shawn K. Desai ◽  
...  

ABSTRACT We developed a series of ligand-inducible riboswitches that control gene expression in diverse species of Gram-negative and Gram-positive bacteria, including human pathogens that have few or no previously reported inducible expression systems. We anticipate that these riboswitches will be useful tools for genetic studies in a wide range of bacteria.


2014 ◽  
Vol 197 (5) ◽  
pp. 882-892 ◽  
Author(s):  
Jessica R. Galloway-Peña ◽  
Xiaowen Liang ◽  
Kavindra V. Singh ◽  
Puja Yadav ◽  
Chungyu Chang ◽  
...  

The WxL domain recently has been identified as a novel cell wall binding domain found in numerous predicted proteins within multiple Gram-positive bacterial species. However, little is known about the function of proteins containing this novel domain. Here, we identify and characterize 6Enterococcus faeciumproteins containing the WxL domain which, by reverse transcription-PCR (RT-PCR) and genomic analyses, are located in three similarly organized operons, deemed WxL loci A, B, and C. Western blotting, electron microscopy, and enzyme-linked immunosorbent assays (ELISAs) determined that genes of WxL loci A and C encode antigenic, cell surface proteins exposed at higher levels in clinical isolates than in commensal isolates. Secondary structural analyses of locus A recombinant WxL domain-containing proteins found they are rich in β-sheet structure and disordered segments. Using Biacore analyses, we discovered that recombinant WxL proteins from locus A bind human extracellular matrix proteins, specifically type I collagen and fibronectin. Proteins encoded by locus A also were found to bind to each other, suggesting a novel cell surface complex. Furthermore, bile salt survival assays and animal models using a mutant from which all three WxL loci were deleted revealed the involvement of WxL operons in bile salt stress and endocarditis pathogenesis. In summary, these studies extend our understanding of proteins containing the WxL domain and their potential impact on colonization and virulence inE. faeciumand possibly other Gram-positive bacterial species.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lisa F. Dawson ◽  
Johann Peltier ◽  
Catherine L. Hall ◽  
Mark A. Harrison ◽  
Maria Derakhshan ◽  
...  

AbstractClostridioides difficile is the leading cause of nosocomial antibiotic-associated diarrhoea worldwide, yet there is little insight into intestinal tract colonisation and relapse. In many bacterial species, the secondary messenger cyclic-di-GMP mediates switching between planktonic phase, sessile growth and biofilm formation. We demonstrate that c-di-GMP promotes early biofilm formation in C. difficile and that four cell surface proteins contribute to biofilm formation, including two c-di-GMP regulated; CD2831 and CD3246, and two c-di-GMP-independent; CD3392 and CD0183. We demonstrate that C. difficile biofilms are composed of extracellular DNA (eDNA), cell surface and intracellular proteins, which form a protective matrix around C. difficile vegetative cells and spores, as shown by a protective effect against the antibiotic vancomycin. We demonstrate a positive correlation between biofilm biomass, sporulation frequency and eDNA abundance in all five C. difficile lineages. Strains 630 (RT012), CD305 (RT023) and M120 (RT078) contain significantly more eDNA in their biofilm matrix than strains R20291 (RT027) and M68 (RT017). DNase has a profound effect on biofilm integrity, resulting in complete disassembly of the biofilm matrix, inhibition of biofilm formation and reduced spore germination. The addition of exogenous DNase could be exploited in treatment of C. difficile infection and relapse, to improve antibiotic efficacy.


2021 ◽  
Author(s):  
Evan Couser ◽  
Jennifer L Chlebek ◽  
Ankur B Dalia

Bacterial surface appendages called type IVa pili (T4aP) promote diverse activities including DNA uptake, twitching motility, and virulence. These activities rely on the ability of T4aP to dynamically extend and retract from the cell surface. Dynamic extension relies on a motor ATPase commonly called PilB. Most T4aP also rely on specific motor ATPases, commonly called PilT and PilU, to dynamically and forcefully retract. Here, we systematically assess whether motor ATPases from 4 distinct T4aP could functionally complement Vibrio cholerae mutants that lacked their endogenous motors. We found that the retraction ATPases PilT and PilU are highly promiscuous and promote retraction of the V. cholerae competence T4aP despite a high degree of sequence divergence. In contrast, orthologous extension ATPases were not able to mediate extension of the V. cholerae competence T4aP despite a similar degree of sequence divergence. Also, we show that one of the PilT orthologs characterized does not support PilU-dependent retraction and we attributed this loss of activity to the 3' end of the gene, which suggests that the C-terminus of PilT plays an important role in promoting PilU-dependent retraction. Together, our data suggest that retraction ATPases have maintained a high degree of promiscuity for promoting retraction of diverse T4aP, while extension ATPases have evolved to become highly specific for their cognate systems.


2020 ◽  
Author(s):  
Gabrielle Larocque ◽  
Penelope J. La-Borde ◽  
Beverley J. Wilson ◽  
Nicholas I. Clarke ◽  
Daniel J. Moore ◽  
...  

Membrane traffic is an important regulator of cell migration through the endocytosis and recycling of cell surface receptors such as integrin heterodimers. Intracellular nanovesicles (INVs), are a recently identified class of transport vesicle that are involved in multiple membrane trafficking steps including the recycling pathway. The only known marker for INVs is Tumor Protein D54 (TPD54/TPD52L2), a member of the TPD52-like protein family. Overexpression of TPD52-like family proteins in cancer has been linked to poor prognosis and an aggressive metastatic phenotype which suggests cell migration may be altered under these conditions. Here we show that TPD54 associates with INVs by directly binding high curvature membrane via a conserved positively charged motif in its C-terminus. We describe how other members of the TPD52-like family are also associated with INVs and we document the Rab GTPase complement of all INVs. Depletion of TPD52-like proteins inhibits cell migration and invasion; and we show that this is likely due to altered integrin recycling. Our study highlights the involvement of INVs in the trafficking of cell surface proteins to generate biologically important outputs in health and disease.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Clara Bouyx ◽  
Marion Schiavone ◽  
Marie-Ange Teste ◽  
Etienne Dague ◽  
Nathalie Sieczkowski ◽  
...  

Fungal adhesins (Als) or flocculins are family of cell surface proteins that mediate adhesion to diverse biotic and abiotic surfaces. A striking characteristic of Als proteins originally identified in the pathogenic Candida albicans is to form functional amyloids that mediate cis-interaction leading to the formation of adhesin nanodomains and trans-interaction between amyloid sequences of opposing cells. In this report, we show that flocculins encoded by FLO11 in Saccharomyces cerevisiae behave like adhesins in C. albicans. To do so, we show that the formation of nanodomains under an external physical force requires a threshold number of amyloid-forming sequences in the Flo11 protein. Then, using a genome editing approach, we constructed strains expressing variants of the Flo11 protein under the endogenous FLO11 promoter, leading to the demonstration that the loss of amyloid-forming sequences strongly reduces cell-cell interaction but has no effect on either plastic adherence or invasive growth in agar, both phenotypes being dependent on the N- and C-terminal ends of Flo11p. Finally, we show that the location of Flo11 is not altered either by the absence of amyloid-forming sequences or by the removal of the N- or C-terminus of the protein.


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