scholarly journals RNAi screen reveals a role for PACSIN2 and caveolins during bacterial cell-to-cell spread

2019 ◽  
Vol 30 (17) ◽  
pp. 2124-2133 ◽  
Author(s):  
Allen G. Sanderlin ◽  
Cassandra Vondrak ◽  
Arianna J. Scricco ◽  
Indro Fedrigo ◽  
Vida Ahyong ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Intercellular Communication ◽  
Bacterial Pathogen ◽  
Host Cells ◽  
Membrane Remodeling ◽  
Host Proteins ◽  
Cellular Components ◽  
Cell Spread ◽  
Host Genes ◽  
Host Tissues

Listeria monocytogenes is a human bacterial pathogen that disseminates through host tissues using a process called cell-to-cell spread. This critical yet understudied virulence strategy resembles a vesicular form of intercellular trafficking that allows L. monocytogenes to move between host cells without escaping the cell. Interestingly, eukaryotic cells can also directly exchange cellular components via intercellular communication pathways (e.g., trans-endocytosis) using cell–cell adhesion, membrane trafficking, and membrane remodeling proteins. Therefore, we hypothesized that L. monocytogenes would hijack these types of host proteins during spread. Using a focused RNA interference screen, we identified 22 host genes that are important for L. monocytogenes spread. We then found that caveolins (CAV1 and CAV2) and the membrane sculpting F-BAR protein PACSIN2 promote L. monocytogenes protrusion engulfment during spread, and that PACSIN2 specifically localizes to protrusions. Overall, our study demonstrates that host intercellular communication pathways may be coopted during bacterial spread and that specific trafficking and membrane remodeling proteins promote bacterial protrusion resolution.

scholarly journals RNAi screen reveals a role for PACSIN2 and caveolins during bacterial cell-to-cell spread

2019 ◽  
Author(s):  
Allen G. Sanderlin ◽  
Cassandra Vondrak ◽  
Arianna J. Scricco ◽  
Indro Fedrigo ◽  
Vida Ahyong ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Membrane Trafficking ◽  
Intercellular Communication ◽  
Bacterial Pathogen ◽  
Rnai Screen ◽  
Host Cells ◽  
Membrane Remodeling ◽  
Host Proteins ◽  
Cell Spread ◽  
Host Tissues

AbstractListeria monocytogenes is a human bacterial pathogen that disseminates through host tissues using a process called cell-to-cell spread. This critical yet understudied virulence strategy resembles a vesicular form of intercellular trafficking that allows L. monocytogenes to move between host cells without escaping the cell. Interestingly, eukaryotic cells can also directly exchange cellular components via intercellular communication pathways (e.g. trans-endocytosis) using cell-cell adhesion, membrane trafficking, and membrane remodeling proteins. Therefore, we hypothesized that L. monocytogenes would hijack these types of host proteins during spread. Using a focused RNAi screen, we identified 22 host genes that are important for L. monocytogenes spread. We then found that caveolins (CAV1 and CAV2) and the membrane sculpting F-BAR protein PACSIN2 promote L. monocytogenes protrusion engulfment during spread, and that PACSIN2 specifically localized to protrusions. Overall, our study demonstrates that host intercellular communication pathways may be co-opted during bacterial spread and that specific trafficking and membrane remodeling proteins promote bacterial protrusion resolution.SummaryThe human bacterial pathogen Listeria monocytogenes disseminates through host tissues using a process called cell-to-cell spread. In this study, Sanderlin et al., discover that host proteins that normally regulate membrane trafficking and membrane remodeling in uninfected settings are also co-opted by Listeria to promote spread.

scholarly journals Compartmentalization of the Broad-Range Phospholipase C Activity to the Spreading Vacuole Is Critical for Listeria monocytogenes Virulence

2006 ◽  
Vol 75 (1) ◽  
pp. 44-51 ◽  
Author(s):  
P. S. Marie Yeung ◽  
Yoojin Na ◽  
Amanda J. Kreuder ◽  
Hélène Marquis
Keyword(s):  
Listeria Monocytogenes ◽  
Phospholipase C ◽  
Membrane Damage ◽  
Bacterial Pathogen ◽  
Host Cells ◽  
Virulence Attenuation ◽  
Infected Cells ◽  
Host Cell Membranes ◽  
Cell Spread

ABSTRACT Listeria monocytogenes is a bacterial pathogen that multiplies in the cytosol of host cells and spreads directly from cell to cell by using an actin-based mechanism of motility. The broad-range phospholipase C (PC-PLC) of L. monocytogenes contributes to bacterial escape from vacuoles formed upon cell-to-cell spread. PC-PLC is made as an inactive proenzyme whose activation requires cleavage of an N-terminal propeptide. During infection, PC-PLC is activated specifically in acidified vacuoles. To assess the importance of compartmentalizing PC-PLC activity during infection, we created a mutant that makes constitutively active PC-PLC (the plcBΔpro mutant). Results from intracellular growth and cell-to-cell spread assays showed that the plcBΔpro mutant was sensitive to gentamicin, suggesting that unregulated PC-PLC activity causes damage to host cell membranes. This was confirmed by the observation of a twofold increase in staining of live infected cells by a non-membrane-permeant DNA fluorescent dye. However, membrane damage was not sufficient to cause cell lysis and was dependent on bacterial cell-to-cell spread, suggesting that damage was localized to bacterium-containing filopodia. Using an in vivo competitive infection assay, we observed that the plcBΔpro mutant was outcompeted up to 200-fold by the wild-type strain in BALB/c mice. Virulence attenuation was greater when mice were infected orally than when they were infected intravenously, presumably because the plcBΔpro mutant was initially outcompeted in the intestines, reducing the number of mutant bacteria reaching the liver and spleen. Together, these results emphasize the importance for L. monocytogenes virulence of compartmentalizing the activity of PC-PLC during infection.

scholarly journals Legionella Subvert the Functions of Rab1 and Sec22b to Create a Replicative Organelle

2004 ◽  
Vol 199 (9) ◽  
pp. 1201-1211 ◽  
Author(s):  
Jonathan C. Kagan ◽  
Mary-Pat Stein ◽  
Marc Pypaert ◽  
Craig R. Roy
Keyword(s):  
Endoplasmic Reticulum ◽  
Legionella Pneumophila ◽  
Molecular Mechanisms ◽  
Bacterial Pathogen ◽  
Host Cells ◽  
Intracellular Growth ◽  
Host Proteins ◽  
Morphological Studies ◽  
Bacterial Replication ◽  
Inhibition Studies

Legionella pneumophila is a bacterial pathogen that infects eukaryotic host cells and replicates inside a specialized organelle that is morphologically similar to the endoplasmic reticulum (ER). To better understand the molecular mechanisms governing transport of the Legionella-containing vacuole (LCV), we have identified host proteins that participate in the conversion of the LCV into a replicative organelle. Our data show that Rab1 is recruited to the LCV within minutes of uptake. Rab1 recruitment to the LCV precedes remodeling of this compartment by ER-derived vesicles. Genetic inhibition studies demonstrate that Rab1 is important for the recruitment of ER-derived vesicles to the LCV and that inhibiting Rab1 function abrogates intracellular growth of Legionella. Morphological studies indicate that the Sec22b protein is located on ER-derived vesicles recruited to the LCV and that Sec22b is delivered to the LCV membrane. Sec22b function was found to be important for biogenesis of the specialized organelle that supports Legionella replication. These studies demonstrate that Legionella has the ability to subvert Rab1 and Sec22b function to facilitate the transport and fusion of ER-derived vesicles with the LCV, resulting in the formation of a specialized organelle that can support bacterial replication.

scholarly journals Cell-to-cell spread of microsporidia causesC. elegansorgans to form syncytia

2016 ◽  
Author(s):  
Keir M. Balla ◽  
Robert J. Luallen ◽  
Malina A. Bakowski ◽  
Emily R. Troemel
Keyword(s):  
Life Cycles ◽  
Host Cells ◽  
Environmental Cues ◽  
Multinucleate Cell ◽  
Host Environment ◽  
Obligate Intracellular ◽  
C Elegans ◽  
Developmental Switch ◽  
Cell Spread ◽  
Host Tissues

AbstractThe growth of pathogens is dictated by their interactions with the host environment. Many obligate intracellular pathogens undergo several cellular decisions as they progress through their life cycles inside of host cells. We studied this process for several species of microsporidia in the genusNematocidain their co-evolved animal hostCaenorhabditis elegans. We found that microsporidia can restructure multicellular host tissues into a single contiguous multinucleate cell. In particular, we found that all threeNematocidaspecies we studied were able to spread across the cells ofC. eleganstissues before forming spores, with two species causing syncytial formation in the intestine, and one species causing syncytial formation in the muscle. We also found that the decision to switch from replication to differentiation inN. parisiiwas altered by the density of infection, suggesting that environmental cues influence the dynamics of the pathogen life cycle. These findings show how microsporidia can maximize the use of host space for growth, and that environmental cues in the host can regulate a developmental switch in the pathogen.

scholarly journals The Posttranslocation Chaperone PrsA2 Contributes to Multiple Facets of Listeria monocytogenes Pathogenesis

2009 ◽  
Vol 77 (7) ◽  
pp. 2612-2623 ◽  
Author(s):  
Francis Alonzo ◽  
Gary C. Port ◽  
Min Cao ◽  
Nancy E. Freitag
Keyword(s):  
Listeria Monocytogenes ◽  
Gene Product ◽  
Bacterial Pathogen ◽  
Virulence Gene ◽  
Host Cells ◽  
Listeriolysin O ◽  
Virulence Gene Expression ◽  
High Concentrations ◽  
Host Infection ◽  
Cell Spread

ABSTRACT Listeria monocytogenes is an intracellular bacterial pathogen whose virulence depends on the regulated expression of numerous secreted bacterial factors. As for other gram-positive bacteria, many proteins secreted by L. monocytogenes are translocated across the bacterial membrane in an unfolded state to the compartment existing between the membrane and the cell wall. This compartment presents a challenging environment for protein folding due to its high density of negative charge, high concentrations of cations, and low pH. We recently identified PrsA2 as a gene product required for L. monocytogenes virulence. PrsA2 was identified based on its increased secretion by strains containing a mutationally activated form of prfA, the key regulator of L. monocytogenes virulence gene expression. The prsA2 gene product is one of at least two predicted peptidyl-prolyl cis/trans-isomerases encoded by L. monocytogenes; these proteins function as posttranslocation protein chaperones and/or foldases. In this study, we demonstrate that PrsA2 plays a unique and important role in L. monocytogenes pathogenesis by promoting the activity and stability of at least two critical secreted virulence factors: listeriolysin O (LLO) and a broad-specificity phospholipase. Loss of PrsA2 activity severely attenuated virulence in mice and impaired bacterial cell-to-cell spread in host cells. In contrast, mutants lacking prsA1 resembled wild-type bacteria with respect to intracellular growth and cell-to-cell spread as well as virulence in mice. PrsA2 is thus distinct from PrsA1 in its unique requirement for the stability and full activity of L. monocytogenes-secreted factors that contribute to host infection.

scholarly journals The type III effector EspF coordinates membrane trafficking by the spatiotemporal activation of two eukaryotic signaling pathways

2007 ◽  
Vol 178 (7) ◽  
pp. 1265-1278 ◽  
Author(s):  
Neal M. Alto ◽  
Andrew W. Weflen ◽  
Matthew J. Rardin ◽  
Defne Yarar ◽  
Cheri S. Lazar ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Gastrointestinal Disease ◽  
Effector Proteins ◽  
Host Cells ◽  
Spatiotemporal Pattern ◽  
Membrane Remodeling ◽  
Type Iii Effector ◽  
Type Iii ◽  
Signaling Complex

Bacterial toxins and effector proteins hijack eukaryotic enzymes that are spatially localized and display rapid signaling kinetics. However, the molecular mechanisms by which virulence factors engage highly dynamic substrates in the host cell environment are poorly understood. Here, we demonstrate that the enteropathogenic Escherichia coli (EPEC) type III effector protein EspF nucleates a multiprotein signaling complex composed of eukaryotic sorting nexin 9 (SNX9) and neuronal Wiskott-Aldrich syndrome protein (N-WASP). We demonstrate that a specific and high affinity association between EspF and SNX9 induces membrane remodeling in host cells. These membrane-remodeling events are directly coupled to N-WASP/Arp2/3–mediated actin nucleation. In addition to providing a biochemical mechanism of EspF function, we find that EspF dynamically localizes to membrane-trafficking organelles in a spatiotemporal pattern that correlates with SNX9 and N-WASP activity in living cells. Thus, our findings suggest that the EspF-dependent assembly of SNX9 and N-WASP represents a novel form of signaling mimicry used to promote EPEC pathogenesis and gastrointestinal disease.

scholarly journals Network-based analysis of virulence factors for uncovering Aeromonas veronii pathogenesis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hong Li ◽  
Xiang Ma ◽  
Yanqiong Tang ◽  
Dan Wang ◽  
Ziding Zhang ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Bacterial Pathogen ◽  
Signal Transduction Pathway ◽  
Immune Defense ◽  
Ppi Network ◽  
Host Proteins ◽  
Homologous Proteins ◽  
Aeromonas Veronii ◽  
Regulatory Systems ◽  
Network Modules

Abstract Background Aeromonas veronii is a bacterial pathogen in aquaculture, which produces virulence factors to enable it colonize and evade host immune defense. Given that experimental verification of virulence factors is time-consuming and laborious, few virulence factors have been characterized. Moreover, most studies have only focused on single virulence factors, resulting in biased interpretation of the pathogenesis of A. veronii. Results In this study, a PPI network at genome-wide scale for A. veronii was first constructed followed by prediction and mapping of virulence factors on the network. When topological characteristics were analyzed, the virulence factors had higher degree and betweenness centrality than other proteins in the network. In particular, the virulence factors tended to interact with each other and were enriched in two network modules. One of the modules mainly consisted of histidine kinases, response regulators, diguanylate cyclases and phosphodiesterases, which play important roles in two-component regulatory systems and the synthesis and degradation of cyclic-diGMP. Construction of the interspecies PPI network between A. veronii and its host Oreochromis niloticus revealed that the virulence factors interacted with homologous proteins in the host. Finally, the structures and interacting sites of the virulence factors during interaction with host proteins were predicted. Conclusions The findings here indicate that the virulence factors probably regulate the virulence of A. veronii by involving in signal transduction pathway and manipulate host biological processes by mimicking and binding competitively to host proteins. Our results give more insight into the pathogenesis of A. veronii and provides important information for designing targeted antibacterial drugs.

scholarly journals The Burkholderia pseudomallei intracellular ‘TRANSITome’

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yun Heacock-Kang ◽  
Ian A. McMillan ◽  
Michael H. Norris ◽  
Zhenxin Sun ◽  
Jan Zarzycki-Siek ◽  
...  
Keyword(s):  
Gene Expression ◽  
Population Dynamics ◽  
Burkholderia Pseudomallei ◽  
Host Cells ◽  
Hypothetical Proteins ◽  
Membrane Protrusion ◽  
Complex Environments ◽  
Cell Infection ◽  
Prokaryotic Cell ◽  
Cell Spread

AbstractProkaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations, which has hampered further understanding of spatiotemporal and stage-specific processes of prokaryotic cells within complex environments. Here we develop a ‘TRANSITomic’ approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection at defined stages, yielding pathophysiological insights. We find that B. pseudomallei transits through host cells during infection in three observable stages: vacuole entry; cytoplasmic escape and replication; and membrane protrusion, promoting cell-to-cell spread. The B. pseudomallei ‘TRANSITome’ reveals dynamic gene-expression flux during transit in host cells and identifies genes that are required for pathogenesis. We find several hypothetical proteins and assign them to virulence mechanisms, including attachment, cytoskeletal modulation, and autophagy evasion. The B. pseudomallei ‘TRANSITome’ provides prokaryotic single-cell transcriptomics information enabling high-resolution understanding of host-pathogen interactions.

scholarly journals Matching the supply of bacterial nutrients to the nutritional demand of the animal host

2014 ◽  
Vol 281 (1791) ◽  
pp. 20141163 ◽  
Author(s):  
Calum W. Russell ◽  
Anton Poliakov ◽  
Meena Haribal ◽  
Georg Jander ◽  
Klaas J. van Wijk ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Acyrthosiphon Pisum ◽  
Feedback Inhibition ◽  
Essential Amino Acids ◽  
Host Cells ◽  
Host Proteins ◽  
Buchnera Aphidicola ◽  
Symbiotic Microorganisms ◽  
Precursor Supply ◽  
Host Regulation

Various animals derive nutrients from symbiotic microorganisms with much-reduced genomes, but it is unknown whether, and how, the supply of these nutrients is regulated. Here, we demonstrate that the production of essential amino acids (EAAs) by the bacterium Buchnera aphidicola in the pea aphid Acyrthosiphon pisum is elevated when aphids are reared on diets from which that EAA are omitted, demonstrating that Buchnera scale EAA production to host demand. Quantitative proteomics of bacteriocytes (host cells bearing Buchnera ) revealed that these metabolic changes are not accompanied by significant change in Buchnera or host proteins, suggesting that EAA production is regulated post-translationally. Bacteriocytes in aphids reared on diet lacking the EAA methionine had elevated concentrations of both methionine and the precursor cystathionine, indicating that methionine production is promoted by precursor supply and is not subject to feedback inhibition by methionine. Furthermore, methionine production by isolated Buchnera increased with increasing cystathionine concentration. We propose that Buchnera metabolism is poised for EAA production at certain maximal rates, and the realized release rate is determined by precursor supply from the host. The incidence of host regulation of symbiont nutritional function via supply of key nutritional inputs in other symbioses remains to be investigated.

Sign in / Sign up

Export Citation Format

Share Document