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Plant Physiology Mar 2022Stomatal movement is essential for plants to optimize transpiration and therefore photosynthesis. Rapid changes in the stomatal aperture are accompanied by adjustment of...
Stomatal movement is essential for plants to optimize transpiration and therefore photosynthesis. Rapid changes in the stomatal aperture are accompanied by adjustment of vacuole volume and morphology in guard cells (GCs). In Arabidopsis (Arabidopsis thaliana) leaf epidermis, stomatal development undergoes a cell-fate transition including four stomatal lineage cells: meristemoid, guard mother cell, young GC, and GC. Little is known about the mechanism underlying vacuole dynamics and vacuole formation during stomatal development. Here, we utilized whole-cell electron tomography (ET) analysis to elucidate vacuole morphology, formation, and development in different stages of stomatal lineage cells at nanometer resolution. The whole-cell ET models demonstrated that large vacuoles were generated from small vacuole stepwise fusion/maturation along stomatal development stages. Further ET analyses verified the existence of swollen intraluminal vesicles inside distinct vacuoles at certain developmental stages of stomatal lineage cells, implying a role of multivesicular body fusion in stomatal vacuole formation. Collectively, our findings demonstrate a mechanism mediating vacuole formation in Arabidopsis stomatal development and may shed light on the role of vacuoles in stomatal movement.
Topics: Arabidopsis; Arabidopsis Proteins; Electron Microscope Tomography; Plant Stomata; Vacuoles
PubMed: 35134219
DOI: 10.1093/plphys/kiac028 -
Nature Communications Jun 2023Liquid droplets of biomolecules play key roles in organizing cellular behavior, and are also technologically relevant, yet physical studies of dynamic processes of such...
Liquid droplets of biomolecules play key roles in organizing cellular behavior, and are also technologically relevant, yet physical studies of dynamic processes of such droplets have generally been lacking. Here, we investigate and quantify the dynamics of formation of dilute internal inclusions, i.e., vacuoles, within a model system consisting of liquid droplets of DNA 'nanostar' particles. When acted upon by DNA-cleaving restriction enzymes, these DNA droplets exhibit cycles of appearance, growth, and bursting of internal vacuoles. Analysis of vacuole growth shows their radius increases linearly in time. Further, vacuoles pop upon reaching the droplet interface, leading to droplet motion driven by the osmotic pressure of restriction fragments captured in the vacuole. We develop a model that accounts for the linear nature of vacuole growth, and the pressures associated with motility, by describing the dynamics of diffusing restriction fragments. The results illustrate the complex non-equilibrium dynamics possible in biomolecular condensates.
Topics: Vacuoles; DNA
PubMed: 37328453
DOI: 10.1038/s41467-023-39175-0 -
Nature Plants Nov 2022Symbioses between legumes and rhizobia require establishment of the plant-derived symbiosome membrane, which surrounds the rhizobia and accommodates the symbionts by...
Symbioses between legumes and rhizobia require establishment of the plant-derived symbiosome membrane, which surrounds the rhizobia and accommodates the symbionts by providing an interface for nutrient and signal exchange. The host cytoskeleton and endomembrane trafficking systems play central roles in the formation of a functional symbiotic interface for rhizobia endosymbiosis; however, the underlying mechanisms remain largely unknown. Here we demonstrate that the nodulation-specific kinesin-like calmodulin-binding protein (nKCBP), a plant-specific microtubule-based kinesin motor, controls central vacuole morphogenesis in symbiotic cells in Medicago truncatula. Phylogenetic analysis further indicated that nKCBP duplication occurs solely in legumes of the clade that form symbiosomes. Knockout of nKCBP results in central vacuole deficiency, defective symbiosomes and abolished nitrogen fixation. nKCBP decorates linear particles along microtubules, and crosslinks microtubules with the actin cytoskeleton, to control central vacuole formation by modulating vacuolar vesicle fusion in symbiotic cells. Together, our findings reveal that rhizobia co-opted nKCBP to achieve symbiotic interface formation by regulating cytoskeletal assembly and central vacuole morphogenesis during nodule development.
Topics: Rhizobium; Symbiosis; Kinesins; Vacuoles; Phylogeny; Plant Proteins; Medicago truncatula; Morphogenesis
PubMed: 36316454
DOI: 10.1038/s41477-022-01261-4 -
International Journal of Molecular... Feb 2023Large vacuoles are a predominant cell organelle throughout the plant body. They maximally account for over 90% of cell volume and generate turgor pressure that acts as a... (Review)
Review
Large vacuoles are a predominant cell organelle throughout the plant body. They maximally account for over 90% of cell volume and generate turgor pressure that acts as a driving force of cell growth, which is essential for plant development. The plant vacuole also acts as a reservoir for sequestering waste products and apoptotic enzymes, thereby enabling plants to rapidly respond to fluctuating environments. Vacuoles undergo dynamic transformation through repeated enlargement, fusion, fragmentation, invagination, and constriction, eventually resulting in the typical 3-dimensional complex structure in each cell type. Previous studies have indicated that such dynamic transformations of plant vacuoles are governed by the plant cytoskeletons, which consist of F-actin and microtubules. However, the molecular mechanism of cytoskeleton-mediated vacuolar modifications remains largely unclear. Here we first review the behavior of cytoskeletons and vacuoles during plant development and in response to environmental stresses, and then introduce candidates that potentially play pivotal roles in the vacuole-cytoskeleton nexus. Finally, we discuss factors hampering the advances in this research field and their possible solutions using the currently available cutting-edge technologies.
Topics: Vacuoles; Cytoskeleton; Microtubules; Plants; Actin Cytoskeleton
PubMed: 36835552
DOI: 10.3390/ijms24044143 -
Annual Review of Microbiology Sep 2020Many intracellular pathogens, including the protozoan parasite , live inside a vacuole that resides in the host cytosol. Vacuolar residence provides these pathogens with... (Review)
Review
Many intracellular pathogens, including the protozoan parasite , live inside a vacuole that resides in the host cytosol. Vacuolar residence provides these pathogens with a defined niche for replication and protection from detection by host cytosolic pattern recognition receptors. However, the limiting membrane of the vacuole, which constitutes the host-pathogen interface, is also a barrier for pathogen effectors to reach the host cytosol and for the acquisition of host-derived nutrients. This review provides an update on the specialized secretion and trafficking systems used by to overcome the barrier of the parasitophorous vacuole membrane and thereby allow the delivery of proteins into the host cell and the acquisition of host-derived nutrients.
Topics: Cytosol; Host-Parasite Interactions; Humans; Metabolic Networks and Pathways; Nutrients; Protein Transport; Protozoan Proteins; Toxoplasma; Vacuoles; Virulence Factors
PubMed: 32680452
DOI: 10.1146/annurev-micro-011720-122318 -
Plant & Cell Physiology Jun 2022Fruit flesh cell vacuoles play a pivotal role in fruit growth and quality formation. In the present study, intact vacuoles were carefully released and collected from...
Fruit flesh cell vacuoles play a pivotal role in fruit growth and quality formation. In the present study, intact vacuoles were carefully released and collected from protoplasts isolated from flesh cells at five sampling times along fig fruit development. Label-free quantification and vacuole proteomic analysis identified 1,251 proteins, 1,137 of which were recruited as differentially abundant proteins (DAPs) by fold change ≥ 1.5, P < 0.05. DAPs were assigned to 10 functional categories; among them, 238, 186, 109, 93 and 90 were annotated as metabolism, transport proteins, membrane fusion or vesicle trafficking, protein fate and stress response proteins, respectively. Decreased numbers of DAPs were uncovered along fruit development. The overall changing pattern of DAPs revealed two major proteome landscape conversions in fig flesh cell vacuoles: the first occurred when fruit developed from late-stage I to mid-stage II, and the second occurred when the fruit started ripening. Metabolic proteins related to glycosidase, lipid and extracellular proteins contributing to carbohydrate storage and vacuole expansion, and protein-degrading proteins determining vacuolar lytic function were revealed. Key tonoplast proteins contributing to vacuole expansion, cell growth and fruit quality formation were also identified. The revealed comprehensive changes in the vacuole proteome during flesh development were compared with our previously published vacuole proteome of grape berry. The information expands our knowledge of the vacuolar proteome and the protein basis of vacuole functional evolution during fruit development and quality formation.
Topics: Ficus; Fruit; Plant Proteins; Proteome; Proteomics; Vacuoles
PubMed: 35348748
DOI: 10.1093/pcp/pcac039 -
Nature Communications Jun 2023Iron is essential to cells as a cofactor in enzymes of respiration and replication, however without correct storage, iron leads to the formation of dangerous oxygen...
Iron is essential to cells as a cofactor in enzymes of respiration and replication, however without correct storage, iron leads to the formation of dangerous oxygen radicals. In yeast and plants, iron is transported into a membrane-bound vacuole by the vacuolar iron transporter (VIT). This transporter is conserved in the apicomplexan family of obligate intracellular parasites, including in Toxoplasma gondii. Here, we assess the role of VIT and iron storage in T. gondii. By deleting VIT, we find a slight growth defect in vitro, and iron hypersensitivity, confirming its essential role in parasite iron detoxification, which can be rescued by scavenging of oxygen radicals. We show VIT expression is regulated by iron at transcript and protein levels, and by altering VIT localization. In the absence of VIT, T. gondii responds by altering expression of iron metabolism genes and by increasing antioxidant protein catalase activity. We also show that iron detoxification has an important role both in parasite survival within macrophages and in virulence in a mouse model. Together, by demonstrating a critical role for VIT during iron detoxification in T. gondii, we reveal the importance of iron storage in the parasite and provide the first insight into the machinery involved.
Topics: Animals; Mice; Toxoplasma; Vacuoles; Reactive Oxygen Species; Membrane Transport Proteins; Parasites; Protozoan Proteins
PubMed: 37339985
DOI: 10.1038/s41467-023-39436-y -
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