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Frontiers in Cellular and Infection... 2017A common strategy among intracellular bacterial pathogens is to enter into a vacuolar environment upon host cell invasion. One such pathogen, , resides within the... (Review)
Review
A common strategy among intracellular bacterial pathogens is to enter into a vacuolar environment upon host cell invasion. One such pathogen, , resides within the -containing vacuole (SCV) inside epithelial cells and macrophages. hijacks the host endosomal system to establish this unique intracellular replicative niche, forming a highly complex and dynamic network of -induced filaments (SIFs). SIFs radiate outwards from the SCV upon onset of bacterial replication. SIF biogenesis is dependent on the activity of bacterial effector proteins secreted by the -pathogenicity island-2 (SPI-2) encoded type III secretion system. While the presence of SIFs has been known for almost 25 years, their precise role during infection remains elusive. This review summarizes our current knowledge of SCV maturation and SIF biogenesis, and recent advances in our understanding of the role of SIFs inside cells.
Topics: Animals; Cytoskeleton; Epithelial Cells; Host-Pathogen Interactions; Humans; Macrophages; Salmonella enterica; Vacuoles
PubMed: 28791257
DOI: 10.3389/fcimb.2017.00335 -
International Journal of Medical... Jan 2018Simkania negevensis is an obligate intracellular Chlamydia-like pathogen of the respiratory tract. It infects and multiplies in a wide range of hosts, from unicellular... (Review)
Review
Simkania negevensis is an obligate intracellular Chlamydia-like pathogen of the respiratory tract. It infects and multiplies in a wide range of hosts, from unicellular amoeba to a variety of human cells, such as epithelial HeLa and macrophage-like THP1 cells. The Simkania-containing vacuole (SnCV) forms close contacts with the endoplasmic reticulum (ER), and recruits and affects mitochondria of the host cells. Simkania prevent ER stress and require the components of the retrograde transport, as well as several mitochondrial and peroxisomal proteins, for proper development. This review recapitulates our current knowledge about the involvement of various cellular organelles in the life cycle of S. negevensis.
Topics: Autophagy; Biological Transport; Chlamydiales; Endoplasmic Reticulum Stress; Gram-Negative Bacterial Infections; Host-Pathogen Interactions; Humans; Organelles; Vacuoles
PubMed: 29089243
DOI: 10.1016/j.ijmm.2017.10.008 -
Cell Host & Microbe Feb 2022Intracellular pathogens commonly reside within macrophages to find shelter from humoral defenses, but host cell death can expose them to the extracellular milieu. We...
Intracellular pathogens commonly reside within macrophages to find shelter from humoral defenses, but host cell death can expose them to the extracellular milieu. We find intracellular pathogens solve this dilemma by using virulence factors to generate a complement-dependent find-me signal that initiates uptake by a new phagocyte through efferocytosis. During macrophage death, Salmonella uses a type III secretion system to perforate the membrane of the pathogen-containing vacuole (PCV), thereby triggering complement deposition on bacteria entrapped in pore-induced intracellular traps (PITs). In turn, complement activation signals neutrophil efferocytosis, a process that shelters intracellular bacteria from the respiratory burst. Similarly, Brucella employs its type IV secretion system to perforate the PCV membrane, which induces complement deposition on bacteria entrapped in PITs. Collectively, this work identifies virulence factor-induced perforation of the PCV as a strategy of intracellular pathogens to generate a find-me signal for efferocytosis.
Topics: Phagocytosis; Type III Secretion Systems; Type IV Secretion Systems; Vacuoles; Virulence Factors
PubMed: 34951948
DOI: 10.1016/j.chom.2021.12.001 -
ELife Mar 2024Membrane contact sites (MCSs) are junctures that perform important roles including coordinating lipid metabolism. Previous studies have indicated that vacuolar...
Membrane contact sites (MCSs) are junctures that perform important roles including coordinating lipid metabolism. Previous studies have indicated that vacuolar fission/fusion processes are coupled with modifications in the membrane lipid composition. However, it has been still unclear whether MCS-mediated lipid metabolism controls the vacuolar morphology. Here, we report that deletion of tricalbins (Tcb1, Tcb2, and Tcb3), tethering proteins at endoplasmic reticulum (ER)-plasma membrane (PM) and ER-Golgi contact sites, alters fusion/fission dynamics and causes vacuolar fragmentation in the yeast . In addition, we show that the sphingolipid precursor phytosphingosine (PHS) accumulates in tricalbin-deleted cells, triggering the vacuolar division. Detachment of the nucleus-vacuole junction (NVJ), an important contact site between the vacuole and the perinuclear ER, restored vacuolar morphology in both cells subjected to high exogenous PHS and Tcb3-deleted cells, supporting that PHS transport across the NVJ induces vacuole division. Thus, our results suggest that vacuolar morphology is maintained by MCSs through the metabolism of sphingolipids.
Topics: Mitochondrial Membranes; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Vacuoles; Sphingolipids; Lipid Metabolism; Cell Membrane
PubMed: 38536872
DOI: 10.7554/eLife.89938 -
Journal of Plant Physiology Aug 2024Vacuoles account for 90% of plant cell volume and play important roles in maintaining osmotic pressure, storing metabolites and lysosomes, compartmentalizing harmful...
Vacuoles account for 90% of plant cell volume and play important roles in maintaining osmotic pressure, storing metabolites and lysosomes, compartmentalizing harmful ions, and storing and reusing minerals. These functions closely relay on the ion channels and transporters located on the tonoplast. The separation of intact vacuoles from plant cells is the key technology utilized in the study of tonoplast-located ion channels and transporters. However, the current vacuole separation methods are available for Arabidopsis and some other dicotyledons but are lacking for monocot crops. In this study, we established a new method for the vacuole separation from wheat mesophyll cells and investigated the transmembrane proton flux of tonoplasts with non-invasive micro-test technology (NMT). Moreover, our study provides a technology for the study of vacuole functions in monocot crops.
Topics: Triticum; Vacuoles; Mesophyll Cells
PubMed: 38761672
DOI: 10.1016/j.jplph.2024.154258 -
Plant, Cell & Environment May 2016Plant cells orchestrate an array of molecular mechanisms for maintaining plasmatic concentrations of essential heavy metal (HM) ions, for example, iron, zinc and copper,... (Review)
Review
Plant cells orchestrate an array of molecular mechanisms for maintaining plasmatic concentrations of essential heavy metal (HM) ions, for example, iron, zinc and copper, within the optimal functional range. In parallel, concentrations of non-essential HMs and metalloids, for example, cadmium, mercury and arsenic, should be kept below their toxicity threshold levels. Vacuolar compartmentalization is central to HM homeostasis. It depends on two vacuolar pumps (V-ATPase and V-PPase) and a set of tonoplast transporters, which are directly driven by proton motive force, and primary ATP-dependent pumps. While HM non-hyperaccumulator plants largely sequester toxic HMs in root vacuoles, HM hyperaccumulators usually sequester them in leaf cell vacuoles following efficient long-distance translocation. The distinct strategies evolved as a consequence of organ-specific differences particularly in vacuolar transporters and in addition to distinct features in long-distance transport. Recent molecular and functional characterization of tonoplast HM transporters has advanced our understanding of their contribution to HM homeostasis, tolerance and hyperaccumulation. Another important part of the dynamic vacuolar sequestration syndrome involves enhanced vacuolation. It involves vesicular trafficking in HM detoxification. The present review provides an updated account of molecular aspects that contribute to the vacuolar compartmentalization of HMs.
Topics: Cell Compartmentation; Inactivation, Metabolic; Metals, Heavy; Plants; Proton Pumps; Vacuoles
PubMed: 26729300
DOI: 10.1111/pce.12706 -
Biochimica Et Biophysica Acta Aug 2016Plants are under the continual threat of changing climatic conditions that are associated with various types of abiotic stresses. In particular, heavy metal... (Review)
Review
Plants are under the continual threat of changing climatic conditions that are associated with various types of abiotic stresses. In particular, heavy metal contamination is a major environmental concern that restricts plant growth. Plants absorb heavy metals along with essential elements from the soil and have evolved different strategies to cope with the accumulation of heavy metals. The use of proteomic techniques is an effective approach to investigate and identify the biological mechanisms and pathways affected by heavy metals and metal-containing nanoparticles. The present review focuses on recent advances and summarizes the results from proteomic studies aimed at understanding the response mechanisms of plants under heavy metal and metal-containing nanoparticle stress. Transport of heavy metal ions is regulated through the cell wall and plasma membrane and then sequestered in the vacuole. In addition, the role of different metal chelators involved in the detoxification and sequestration of heavy metals is critically reviewed, and changes in protein profiles of plants exposed to metal-containing nanoparticles are discussed in detail. Finally, strategies for gaining new insights into plant tolerance mechanisms to heavy metal and metal-containing nanoparticle stress are presented. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock.
Topics: Cell Membrane; Crops, Agricultural; Metal Nanoparticles; Metals, Heavy; Stress, Physiological; Vacuoles
PubMed: 26940747
DOI: 10.1016/j.bbapap.2016.02.020 -
Trends in Microbiology May 2024In the tug-of-war between host and pathogen, both evolve to combat each other's defence arsenals. Intracellular phagosomal bacteria have developed strategies to modify... (Review)
Review
In the tug-of-war between host and pathogen, both evolve to combat each other's defence arsenals. Intracellular phagosomal bacteria have developed strategies to modify the vacuolar niche to suit their requirements best. Conversely, the host tries to target the pathogen-containing vacuoles towards the degradative pathways. The host cells use a robust system through intracellular trafficking to maintain homeostasis inside the cellular milieu. In parallel, intracellular bacterial pathogens have coevolved with the host to harbour strategies to manipulate cellular pathways, organelles, and cargoes, facilitating the conversion of the phagosome into a modified pathogen-containing vacuole (PCV). Key molecular regulators of intracellular traffic, such as changes in the organelle (phospholipid) composition, recruitment of small GTPases and associated effectors, soluble N-ethylmaleimide-sensitive factor-activating protein receptors (SNAREs), etc., are hijacked to evade lysosomal degradation. Legionella, Salmonella, Coxiella, Chlamydia, Mycobacterium, and Brucella are examples of pathogens which diverge from the endocytic pathway by using effector-mediated mechanisms to overcome the challenges and establish their intracellular niches. These pathogens extensively utilise and modulate the end processes of secretory pathways, particularly SNAREs, in repurposing the PCV into specialised compartments resembling the host organelles within the secretory network; at the same time, they avoid being degraded by the host's cellular mechanisms. Here, we discuss the recent research advances on the host-pathogen interaction/crosstalk that involves host SNAREs, conserved cellular processes, and the ongoing host-pathogen defence mechanisms in the molecular arms race against each other. The current knowledge of SNAREs, and intravacuolar bacterial pathogen interactions, enables us to understand host cellular innate immune pathways, maintenance of homeostasis, and potential therapeutic strategies to combat ever-growing antimicrobial resistance.
Topics: Host-Pathogen Interactions; Vacuoles; Humans; SNARE Proteins; Bacteria; Phagosomes; Animals; Legionella; Homeostasis
PubMed: 38040624
DOI: 10.1016/j.tim.2023.11.002 -
Methods in Molecular Biology (Clifton,... 2018In plant cells, vacuoles are extremely important for growth and development, and influence important cellular functions as photosynthesis, respiration, and...
In plant cells, vacuoles are extremely important for growth and development, and influence important cellular functions as photosynthesis, respiration, and transpiration. Plant cells contain lytic and storage vacuoles, whose size can be different depending on cell type and tissue developmental stage. One of the main roles of vacuoles is to regulate the cell turgor in response to different stimuli. Thus, studying the morphology, dynamics, and physiology of vacuole is fundamentally important to advance knowledge in plant cell biology at large. The availability of fluorescent probes allows marking vacuoles in multiple ways. These may be fast, when using commercially available chemical dyes, or relatively slow, in the case of specific genetically encoded markers based on proteins directed either to the membrane of the vacuole (tonoplast) or to the vacuole lumen. Any of these approaches provides useful information about the morphology and physiology of the vacuole.
Topics: Arabidopsis; Arabidopsis Proteins; Fluorescent Dyes; Luminescent Proteins; Microscopy, Confocal; Neutral Red; Pyridinium Compounds; Quaternary Ammonium Compounds; Staining and Labeling; Vacuoles
PubMed: 29916071
DOI: 10.1007/978-1-4939-7856-4_5 -
Trends in Parasitology Feb 2020When a malaria parasite invades a host erythrocyte it pushes itself in and invaginates a portion of the host membrane, thereby sealing itself inside and establishing... (Review)
Review
When a malaria parasite invades a host erythrocyte it pushes itself in and invaginates a portion of the host membrane, thereby sealing itself inside and establishing itself in the resulting vacuole. The parasitophorous vacuolar membrane (PVM) that surrounds the parasite is modified by the parasite, using its secretory organelles. To survive within this enveloping membrane, the organism must take in nutrients, secrete wastes, export proteins into the host cell, and eventually egress. Here, we review current understanding of the unique solutions Plasmodium has evolved to these challenges and discuss the remaining questions.
Topics: Erythrocytes; Host-Parasite Interactions; Humans; Malaria; Plasmodium; Vacuoles
PubMed: 31866184
DOI: 10.1016/j.pt.2019.11.006