scholarly journals Previously uncharacterized Salmonella enterica genes required for swarming play a role in seedling colonization

Microbiology ◽  
2009 ◽  
Vol 155 (11) ◽  
pp. 3701-3709 ◽  
Author(s):  
Jeri D. Barak ◽  
Lisa Gorski ◽  
Anita S. Liang ◽  
Koh-Eun Narm
Keyword(s):  
Salmonella Enterica ◽  
Molecular Mechanisms ◽  
Plant Colonization ◽  
In Planta ◽  
Associated Bacteria ◽  
Biofilm Production ◽  
C Terminus ◽  
Alfalfa Seed ◽  
Osmotic Agent

Incidences of bacterial foodborne illness caused by ingestion of fresh produce are rising. Instead of this being due to incidental contamination, the animal pathogen Salmonella enterica utilizes specific molecular mechanisms to attach to and colonize plants. This work characterizes two S. enterica genes of unknown function: a putative periplasmic protein, STM0278, and a putative protein with a hydrolase in the C-terminus, STM0650. STM0278 and STM0650 are important for seedling colonization but appear to have different roles during the process of colonization. Mutants of either STM0278 or STM0650 showed reduced colonization of alfalfa seedlings at 24 h, and the STM0278 mutant also showed reduced colonization at 48 h. Both genes were expressed in planta at 4 h following inoculation of 3-day-old seedlings and at 72 h after seed inoculation. This suggests that the role of STM0650 in seedling colonization is less important later in the process or is duplicated by other mechanisms. Mutants of STM0278 and STM0650 were defective in swarming. The STM0278 mutant failed to swarm in 24 h, while swarming of the STM0650 mutant was delayed. Addition of surfactant restored swarming of the STM0278 mutant, suggesting that STM0278 is involved in surfactant or osmotic agent production or deployment. Alfalfa seed exudates as the sole nutrient source were capable of perpetuating S. enterica swarming. Sequence analysis revealed sequences homologous to STM0278 and STM0650 in plant-associated bacteria, but none in Escherichia coli. Phylogenetic analysis of STM0650 showed similar sequences from diverse classes of plant-associated bacteria. Bacteria that preferentially colonize roots, including S. enterica, may use a similar hydrolase for swarming or biofilm production on plants. Multicellular behaviours by S. enterica appear central to plant colonization. S. enterica genes involved in plant colonization and survival outside of a host are most likely among the ‘function unknown’ genes of this bacterium.

scholarly journals Deletion of the Actin-Associated Tropomyosin Tpm3 Leads to Reduced Cell Complexity in Cultured Hippocampal Neurons—New Insights into the Role of the C-Terminal Region of Tpm3.1

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 715
Author(s):  
Tamara Tomanić ◽  
Claire Martin ◽  
Holly Stefen ◽  
Esmeralda Parić ◽  
Peter Gunning ◽  
...  
Keyword(s):  
Amino Acid ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Growth Cones ◽  
Amino Acid Residues ◽  
Terminal Amino Acid ◽  
C Terminus ◽  
Primary Mouse ◽  
Terminal Amino

Tropomyosins (Tpms) have been described as master regulators of actin, with Tpm3 products shown to be involved in early developmental processes, and the Tpm3 isoform Tpm3.1 controlling changes in the size of neuronal growth cones and neurite growth. Here, we used primary mouse hippocampal neurons of C57/Bl6 wild type and Bl6Tpm3flox transgenic mice to carry out morphometric analyses in response to the absence of Tpm3 products, as well as to investigate the effect of C-terminal truncation on the ability of Tpm3.1 to modulate neuronal morphogenesis. We found that the knock-out of Tpm3 leads to decreased neurite length and complexity, and that the deletion of two amino acid residues at the C-terminus of Tpm3.1 leads to more detrimental changes in neurite morphology than the deletion of six amino acid residues. We also found that Tpm3.1 that lacks the 6 C-terminal amino acid residues does not associate with stress fibres, does not segregate to the tips of neurites, and does not impact the amount of the filamentous actin pool at the axonal growth cones, as opposed to Tpm3.1, which lacks the two C-terminal amino acid residues. Our study provides further insight into the role of both Tpm3 products and the C-terminus of Tpm3.1, and it forms the basis for future studies that aim to identify the molecular mechanisms underlying Tpm3.1 targeting to different subcellular compartments.

scholarly journals The TUTase URT1 connects decapping activators and prevents the accumulation of excessively deadenylated mRNAs to avoid siRNA biogenesis

2020 ◽  
Author(s):  
Hélène Scheer ◽  
Caroline de Almeida ◽  
Emilie Ferrier ◽  
Quentin Simonnot ◽  
Laure Poirier ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Growth And Development ◽  
Molecular Mechanisms ◽  
Tail Length ◽  
Mrna Degradation ◽  
In Planta ◽  
Rna Helicases ◽  
Eukaryotic Mrnas

AbstractUridylation is a widespread modification destabilizing eukaryotic mRNAs. Yet, molecular mechanisms underlying TUTase-mediated mRNA degradation remain mostly unresolved. Here, we report that the Arabidopsis TUTase URT1 participates in a molecular network connecting several translational repressors/decapping activators. URT1 directly interacts with DECAPPING 5 (DCP5), the Arabidopsis ortholog of human LSM14 and yeast Scd6, and this interaction connects URT1 to additional decay factors like DDX6/Dhh1-like RNA helicases. Nanopore direct RNA sequencing reveals a global role of URT1 in shaping poly(A) tail length, notably by preventing the accumulation of excessively deadenylated mRNAs. Based on in vitro and in planta data, we propose a model that explains how URT1 could reduce the accumulation of oligo(A)-tailed mRNAs both by favoring their degradation and because 3’ terminal uridines intrinsically hinder deadenylation. Importantly, preventing the accumulation of excessively deadenylated mRNAs avoids the biogenesis of illegitimate siRNAs that silence endogenous mRNAs and perturb Arabidopsis growth and development.

scholarly journals The C-Terminus Tail Regulates ERK3 Kinase Activity and Its Ability in Promoting Cancer Cell Migration and Invasion

2020 ◽  
Vol 21 (11) ◽  
pp. 4044 ◽  
Author(s):  
Lobna Elkhadragy ◽  
Hadel Alsaran ◽  
Weiwen Long
Keyword(s):  
Cell Migration ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Molecular Mechanisms ◽  
Kinase Activity ◽  
Migration And Invasion ◽  
Cancer Cell Migration ◽  
Cell Migration And Invasion ◽  
C Terminus

Extracellular signal-regulated kinase 3 (ERK3) is an atypical member of the mitogen-activated protein kinase (MAPK) family. It harbors a kinase domain in the N-terminus and a long C-terminus extension. The C-terminus extension comprises a conserved in ERK3 and ERK4 (C34) region and a unique C-terminus tail, which was shown to be required for the interaction of ERK3 with the cytoskeletal protein septin 7. Recent studies have elucidated the role of ERK3 signaling in promoting the motility and invasiveness of cancer cells. However, little is known about the intramolecular regulation of the enzymatic activity and cellular functions of ERK3. In this study, we investigated the role of the elongated C-terminus extension in regulating ERK3 kinase activity and its ability to promote cancer cell migration and invasion. Our study revealed that the deletion of the C-terminus tail greatly diminishes the ability of ERK3 to promote the migration and invasion of lung cancer cells. We identified two molecular mechanisms underlying this effect. Firstly, the deletion of the C-terminus tail decreases the kinase activity of ERK3 towards substrates, including the oncogenic protein steroid receptor co-activator 3 (SRC-3), an important downstream target for ERK3 signaling in cancer. Secondly, in line with the previous finding that the C-terminus tail mediates the interaction of ERK3 with septin 7, we found that the depletion of septin 7 abolished the ability of ERK3 to promote migration, indicating that septin 7 acts as a downstream effector for ERK3-induced cancer cell migration. Taken together, the findings of this study advance our understanding of the molecular regulation of ERK3 signaling by unraveling the role of the C-terminus tail in regulating ERK3 kinase activity and functions in cancer cells. These findings provide useful insights for the development of therapeutic agents targeting ERK3 signaling in cancer.

scholarly journals The conserved arginine required for AvrRps4 processing is also required for recognition of its N-terminal fragment in lettuce

2020 ◽  
Author(s):  
Jianbin Su ◽  
Quang-Minh Nguyen ◽  
Ashten Kimble ◽  
Sharon M. Pike ◽  
Sang Hee Kim ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
In Planta ◽  
Type Iii ◽  
Secretion Signal ◽  
C Terminus ◽  
Secretion Signal Peptide ◽  
Effector Triggered Immunity ◽  
Positively Charged

Pathogens utilize a repertoire of effectors to facilitate pathogenesis, but when the host recognizes one of them it causes effector-triggered immunity. The Pseudomonas type III effector AvrRps4 is a bipartite effector that is processed in planta into a functional 133 amino acid N-terminus (AvrRps4-N) and 88 amino acid C-terminus (AvrRps4-C). Previous studies found AvrRps4-C to be sufficient to trigger HR in turnip. In contrast, our recent work found that AvrRps4-N, but not AvrRps4-C, triggered HR in lettuce whereas both were required for resistance induction in Arabidopsis. Here, we initially compared AvrRps4 recognition by turnip and lettuce using transient expression. By serial truncation, we identified the central conserved region consisting of 37 amino acids as essential for AvrRps4-N recognition, whereas the putative type III secretion signal peptide or the C-terminal 13 amino acids were dispensable. Surprisingly, the conserved arginine at position 112 (R112) that is required for full-length AvrRps4 processing is also required for the recognition of AvrRps4-N by lettuce. Mutating R112 to hydrophobic leucine or negatively charged glutamate abolished the HR-inducing capacity of AvrRps4-N, while a positively charged lysine at this position resulted in a slow and weak HR. Together, our results suggest an AvrRps4-N recognition-specific role of R112 in lettuce.

scholarly journals The making of a Lewy body: the role of alpha-synuclein post-fibrillization modifications in regulating the formation and the maturation of pathological inclusions.

2018 ◽  
Author(s):  
Anne-Laure Mahul-Mellier ◽  
Firat Altay ◽  
Johannes Burtscher ◽  
Niran Maharjan ◽  
Nadine Ait Bouziad ◽  
...  
Keyword(s):  
Lewy Body ◽  
Molecular Mechanisms ◽  
Alpha Synuclein ◽  
Therapeutic Strategies ◽  
Proteolytic Processing ◽  
Primary Neurons ◽  
Cellular Mechanisms ◽  
C Terminus ◽  
Imaging Approach

Although converging evidence point to alpha-synuclein (a-syn) aggregation and Lewy body (LB) formation as central events in Parkinson's disease (PD), the molecular mechanisms that regulate these processes and their role in disease pathogenesis remain poorly understood. Herein, we applied an integrative biochemical, structural and imaging approach to elucidate the sequence, molecular and cellular mechanisms that regulate LB formation in primary neurons. Our results establish that post-fibrillization C-terminal truncation mediated by calpains 1 and 2 and potentially other enzymes, plays critical roles in regulating a-syn seeding, fibrillization and orchestrates many of the events associated with LB formation and maturation. These findings combined with the abundance of a-syn truncated species in LBs and pathological a-syn aggregates have significant implications for ongoing efforts to develop therapeutic strategies based on targeting the C-terminus of a-syn or proteolytic processing of this region.

scholarly journals The TUTase URT1 connects decapping activators and prevents the accumulation of excessively deadenylated mRNAs to avoid siRNA biogenesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hélène Scheer ◽  
Caroline de Almeida ◽  
Emilie Ferrier ◽  
Quentin Simonnot ◽  
Laure Poirier ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Growth And Development ◽  
Molecular Mechanisms ◽  
Tail Length ◽  
Mrna Degradation ◽  
In Planta ◽  
Rna Helicases ◽  
Eukaryotic Mrnas

AbstractUridylation is a widespread modification destabilizing eukaryotic mRNAs. Yet, molecular mechanisms underlying TUTase-mediated mRNA degradation remain mostly unresolved. Here, we report that the Arabidopsis TUTase URT1 participates in a molecular network connecting several translational repressors/decapping activators. URT1 directly interacts with DECAPPING 5 (DCP5), the Arabidopsis ortholog of human LSM14 and yeast Scd6, and this interaction connects URT1 to additional decay factors like DDX6/Dhh1-like RNA helicases. Nanopore direct RNA sequencing reveals a global role of URT1 in shaping poly(A) tail length, notably by preventing the accumulation of excessively deadenylated mRNAs. Based on in vitro and in planta data, we propose a model that explains how URT1 could reduce the accumulation of oligo(A)-tailed mRNAs both by favoring their degradation and because 3’ terminal uridines intrinsically hinder deadenylation. Importantly, preventing the accumulation of excessively deadenylated mRNAs avoids the biogenesis of illegitimate siRNAs that silence endogenous mRNAs and perturb Arabidopsis growth and development.

scholarly journals Role of the Salmonella Pathogenicity Island 1 Effector Proteins SipA, SopB, SopE, and SopE2 in Salmonella enterica Subspecies 1 Serovar Typhimurium Colitis in Streptomycin-Pretreated Mice

2004 ◽  
Vol 72 (2) ◽  
pp. 795-809 ◽  
Author(s):  
Siegfried Hapfelmeier ◽  
Kristin Ehrbar ◽  
Bärbel Stecher ◽  
Manja Barthel ◽  
Marcus Kremer ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Molecular Mechanisms ◽  
Intestinal Inflammation ◽  
Pathogenicity Island ◽  
Effector Proteins ◽  
Host Cells ◽  
Starting Point ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica subspecies 1 serovar Typhimurium (serovar Typhimurium) induces enterocolitis in humans and cattle. The mechanisms of enteric salmonellosis have been studied most extensively in calf infection models. The previous studies established that effector protein translocation into host cells via the Salmonella pathogenicity island 1 (SPI-1) type III secretion system (TTSS) is of central importance in serovar Typhimurium enterocolitis. We recently found that orally streptomycin-pretreated mice provide an alternative model for serovar Typhimurium colitis. In this model the SPI-1 TTSS also plays a key role in the elicitation of intestinal inflammation. However, whether intestinal inflammation in calves and intestinal inflammation in streptomycin-pretreated mice are induced by the same SPI-1 effector proteins is still unclear. Therefore, we analyzed the role of the SPI-1 effector proteins SopB/SigD, SopE, SopE2, and SipA/SspA in elicitation of intestinal inflammation in the murine model. We found that sipA, sopE, and, to a lesser degree, sopE2 contribute to murine colitis, but we could not assign an inflammation phenotype to sopB. These findings are in line with previous studies performed with orally infected calves. Extending these observations, we demonstrated that in addition to SipA, SopE and SopE2 can induce intestinal inflammation independent of each other and in the absence of SopB. In conclusion, our data corroborate the finding that streptomycin-pretreated mice provide a useful model for studying the molecular mechanisms of serovar Typhimurium colitis and are an important starting point for analysis of the molecular events triggered by SopE, SopE2, and SipA in vivo.

scholarly journals Disruption of AtHAK/KT/KUP9 enhances plant cesium accumulation under low potassium supply

2020 ◽  
Author(s):  
Laure Genies ◽  
Ludovic Martin ◽  
Satomi Kanno ◽  
Serge Chiarenza ◽  
Loïc Carasco ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Primary Role ◽  
In Planta ◽  
Experimental Conditions ◽  
Low Potassium ◽  
Significant Impairment ◽  
Potassium Supply ◽  
Mutant Lines ◽  
Low K

ABSTRACTUnderstanding molecular mechanisms which underlie transport of cesium (Cs+) in plants is important to limit entry of its radioisotopes from contaminated area to the food chain. The potentially toxic element Cs+, which is not involved in any biological process, is chemically closed to the macronutrient potassium (K+). Among the multiple K+ carriers, the high-affinity K+ transporters family HAK/KT/KUP is thought to be relevant in mediating opportunistic Cs+ transport. On the 13 KUP identified in Arabidopsis thaliana, only HAK5, the major contributor to root K+ acquisition under low K+ supply, has been functionally demonstrated to be involved in Cs+ uptake in planta. In the present study, we showed that accumulation of Cs+ increased by up to 30% in two A. thaliana mutant lines lacking KUP9 and grown under low K+ supply. Since further experiments revealed that Cs+ release from contaminated plants to the external medium is proportionally lower in the two kup9 mutants, we proposed that KUP9 disruption could impair Cs+ efflux. By contrast, we did not measure significant impairment of K+ status in kup9 mutants suggesting that KUP9 disruption does not alter substantially K+ transport in experimental conditions used here. Putative primary role of KUP9 in plants is further discussed.

scholarly journals A phospho-regulated ensemble signal motif of α-TAT1 drives dynamic microtubule acetylation

2020 ◽  
Author(s):  
Abhijit Deb Roy ◽  
Evan G. Gross ◽  
Gayatri S. Pillai ◽  
Shailaja Seetharaman ◽  
Sandrine Etienne-Manneville ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Molecular Mechanisms ◽  
Cellular Functions ◽  
Intrinsically Disordered ◽  
Phosphorylated Form ◽  
C Terminus ◽  
Cancer Mutations ◽  
Functional Consequences ◽  
Dynamic Microtubule

AbstractSpatiotemporal patterns of microtubule modifications such as acetylation underlie diverse cellular functions. While the molecular identity of the acetylating agent, α-tubulin N-acetyltransferase 1 (α-TAT1), as well as the functional consequences of microtubule acetylation have been revealed, the molecular mechanisms that regulate multi-tasking α-TAT1 action for dynamic acetylation remain obscure. Here we identified a signal motif in the intrinsically disordered C-terminus of α-TAT1, which comprises three functional elements - nuclear export, nuclear import and cytosolic retention. Their balance is tuned via phosphorylation by serine-threonine kinases to determine subcellular localization of α-TAT1. While the phosphorylated form binds to 14-3-3 adapters and accumulates in the cytosol for maximal substrate access, the non-phosphorylated form is sequestered inside the nucleus, thus keeping microtubule acetylation minimal. As cancer mutations have been reported to this motif, the unique ensemble regulation of α-TAT1 localization may hint at a role of microtubule acetylation in aberrant physiological conditions.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

Sign in / Sign up

Export Citation Format

Share Document