-
PloS One 2022Vacuoles in plants and fungi play critical roles in cell metabolism and osmoregulation. To support these functions, vacuoles change their morphology, e.g. they fragment...
Vacuoles in plants and fungi play critical roles in cell metabolism and osmoregulation. To support these functions, vacuoles change their morphology, e.g. they fragment when these organisms are challenged with draught, high salinity or metabolic stress (e.g. acetate accumulation). In turn, morphology reflects an equilibrium between membrane fusion and fission that determines size, shape and copy number. By studying Saccharomyces cerevisiae and its vacuole as models, conserved molecular mechanisms responsible for fusion have been revealed. However, a detailed understanding of vacuole fission and how these opposing processes respond to metabolism or osmoregulation remain elusive. Herein we describe a new fluorometric assay to measure yeast vacuole fission in vitro. For proof-of-concept, we use this assay to confirm that acetate, a metabolic stressor, triggers vacuole fission and show it blocks homotypic vacuole fusion in vitro. Similarly, hypertonic stress induced by sorbitol or glucose caused robust vacuole fission in vitro whilst inhibiting fusion. Using wortmannin to inhibit phosphatidylinositol (PI) -kinases or rGyp1-46 to inactivate Rab-GTPases, we show that acetate stress likely targets PI signaling, whereas osmotic stress affects Rab signaling on vacuole membranes to stimulate fission. This study sets the stage for further investigation into the mechanisms that change vacuole morphology to support cell metabolism and osmoregulation.
Topics: Acetates; Membrane Fusion; Osmotic Pressure; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Vacuoles
PubMed: 35834522
DOI: 10.1371/journal.pone.0271199 -
Autophagy Sep 2019Based on my reading, and on my own experience, I have come to realize that people learn in different ways, and this can include the use of different media. This is one...
Based on my reading, and on my own experience, I have come to realize that people learn in different ways, and this can include the use of different media. This is one reason I have worked with various artists to portray the topic of autophagy through paintings, music and dance. Indeed, comments from members of the audience who have attended one of my seminars often suggest that a particular artistic approach 'hit home' and added meaning to them about the topic. In this issue of the journal I describe another such project-'the-found-art vacuole'-that utilized the talents of an amazing watercolor painter, Scott Hartley. The object of Scott's painting is the only artophagy composition that I have 'made'-assembled is a more accurate word. Doing so was quite fun, but after examining many of the 'antique' items that form the 'found-art vacuole', I realized that it would be nice to have a painting that was done in exquisite detail. The requirement for detail immediately made me think of Scott, whose work I was familiar with from the Ann Arbor Art Fair. To quote a line from the Belleville News-Democrat describing Scott's taking first place in an art competition, 'He began by doing landscapes, and eventually found a different style for his work: the intricacies of urban architecture, of alleys and fire escapes in a city neighborhood.' This does describe the nature of Scott's work, but you have to see these paintings to appreciate the detail.
Topics: Autophagy; Music; Paintings; Saccharomyces cerevisiae; Vacuoles
PubMed: 31238790
DOI: 10.1080/15548627.2019.1630225 -
Plant Molecular Biology Nov 2019Short review focussing on the role and targeting of vacuolar substructure in plant immunity and pathogenesis. Plants lack specialized immune cells, therefore each plant... (Review)
Review
Short review focussing on the role and targeting of vacuolar substructure in plant immunity and pathogenesis. Plants lack specialized immune cells, therefore each plant cell must defend itself against invading pathogens. A typical plant defense strategy is the hypersensitive response that results in host cell death at the site of infection, a process largely regulated by the vacuole. In plant cells, the vacuole is a vital organelle that plays a central role in numerous fundamental processes, such as development, reproduction, and cellular responses to biotic and abiotic stimuli. It shows divergent membranous structures that are continuously transforming. Recent technical advances in visualization and live-cell imaging have significantly altered our view of the vacuolar structures and their dynamics. Understanding the active nature of the vacuolar structures and the mechanisms of vacuole-mediated defense responses is of great importance in understanding plant-pathogen interactions. In this review, we present an overview of the current knowledge about the vacuole and its internal structures, as well as their role in plant-microbe interactions. There is so far limited information on the modulation of the vacuolar structures by pathogens, but recent research has identified the vacuole as a possible target of microbial interference.
Topics: Biomarkers; Cell Death; Host-Pathogen Interactions; Intracellular Membranes; Plant Immunity; Plant Proteins; Plants; Vacuoles
PubMed: 31621005
DOI: 10.1007/s11103-019-00921-y -
Biochimica Et Biophysica Acta.... May 2019Cellular ageing results in accumulating damage to various macromolecules and the progressive decline of organelle function. Yeast vacuoles as well as their counterpart... (Review)
Review
Cellular ageing results in accumulating damage to various macromolecules and the progressive decline of organelle function. Yeast vacuoles as well as their counterpart in higher eukaryotes, the lysosomes, emerge as central organelles in lifespan determination. These acidic organelles integrate enzymatic breakdown and recycling of cellular waste with nutrient sensing, storage, signalling and mobilization. Establishing physical contact with virtually all other organelles, vacuoles serve as hubs of cellular homeostasis. Studies in Saccharomyces cerevisiae contributed substantially to our understanding of the ageing process per se and the multifaceted roles of vacuoles/lysosomes in the maintenance of cellular fitness with progressing age. Here, we discuss the multiple roles of the vacuole during ageing, ranging from vacuolar dynamics and acidification as determinants of lifespan to the function of this organelle as waste bin, recycling facility, nutrient reservoir and integrator of nutrient signalling.
Topics: Lysosomes; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Time Factors; Vacuoles
PubMed: 30796938
DOI: 10.1016/j.bbamcr.2019.02.011 -
Annual Review of Plant Biology Apr 2018Plants have evolved sophisticated mechanisms to recycle intracellular constituents, which are essential for developmental and metabolic transitions; for efficient... (Review)
Review
Plants have evolved sophisticated mechanisms to recycle intracellular constituents, which are essential for developmental and metabolic transitions; for efficient nutrient reuse; and for the proper disposal of proteins, protein complexes, and even entire organelles that become obsolete or dysfunctional. One major route is autophagy, which employs specialized vesicles to encapsulate and deliver cytoplasmic material to the vacuole for breakdown. In the past decade, the mechanics of autophagy and the scores of components involved in autophagic vesicle assembly have been documented. Now emerging is the importance of dedicated receptors that help recruit appropriate cargo, which in many cases exploit ubiquitylation as a signal. Although operating at a low constitutive level in all plant cells, autophagy is upregulated during senescence and various environmental challenges and is essential for proper nutrient allocation. Its importance to plant metabolism and energy balance in particular places autophagy at the nexus of robust crop performance, especially under suboptimal conditions.
Topics: Autophagy; Endocytosis; Models, Biological; Plant Cells; Plant Development; Vacuoles
PubMed: 29539270
DOI: 10.1146/annurev-arplant-042817-040606 -
Seminars in Cell & Developmental Biology Aug 2018Plant architecture follows the need to collect CO solar energy, water and mineral nutrients via large surface areas. It is by the presence of a central vacuole that... (Review)
Review
Plant architecture follows the need to collect CO solar energy, water and mineral nutrients via large surface areas. It is by the presence of a central vacuole that fills much of the cell volume that plants manage to grow at low metabolic cost. In addition vacuoles buffer the fluctuating supply of essential nutrients and help to detoxify the cytosol when plants are challenged by harmful molecules. Despite their large size and multiple important functions, our knowledge of vacuole biogenesis and the machinery underlying their amazing dynamics is still fragmentary. In this review, we try to reconcile past and present models for vacuole biogenesis with the current knowledge of multiple parallel vacuolar trafficking pathways and the molecular machineries driving membrane fusion and organelle shape.
Topics: Arabidopsis; Arabidopsis Proteins; Membrane Fusion; Membrane Proteins; Plants; Protein Transport; Vacuoles
PubMed: 28694113
DOI: 10.1016/j.semcdb.2017.07.008 -
Journal of Experimental Botany Jun 2017Vacuoles play a fundamental role in storage and remobilization of various nutrients, including phosphorus (P), an essential element for cell growth and development.... (Review)
Review
Vacuoles play a fundamental role in storage and remobilization of various nutrients, including phosphorus (P), an essential element for cell growth and development. Cells acquire P primarily in the form of inorganic orthophosphate (Pi). However, the form of P stored in vacuoles varies by organism and tissue. Algae and yeast store polyphosphates (polyPs), whereas plants store Pi and inositol phosphates (InsPs) in vegetative tissues and seeds, respectively. In this review, we summarize how vacuolar P molecules are stored and reallocated and how these processes are regulated and co-ordinated. The roles of SYG1/PHO81/XPR1 (SPX)-domain-containing membrane proteins in allocating vacuolar P are outlined. We also highlight the importance of vacuolar P in buffering the cytoplasmic Pi concentration to maintain cellular homeostasis when the external P supply fluctuates, and present additional roles for vacuolar polyP and InsP besides being a P reserve. Furthermore, we discuss the possibility of alternative pathways to recycle Pi from other P metabolites in vacuoles. Finally, future perspectives for researching this topic and its potential application in agriculture are proposed.
Topics: Membrane Proteins; Phosphorus; Plant Proteins; Plants; Vacuoles; Yeasts
PubMed: 28077447
DOI: 10.1093/jxb/erw481 -
Cellular Microbiology Jul 2015Bacteria of the genus Brucella are intracellular vacuolar pathogens of mammals that cause the worldwide zoonosis brucellosis, and reside within phagocytes of infected... (Review)
Review
Bacteria of the genus Brucella are intracellular vacuolar pathogens of mammals that cause the worldwide zoonosis brucellosis, and reside within phagocytes of infected hosts to promote their survival, persistence and proliferation. These traits are essential to the bacterium's ability to cause disease and have been the subject of much investigation to gain an understanding of Brucella pathogenic mechanisms. Although the endoplasmic reticulum-derived nature of the Brucella replicative niche has been long known, major strides have recently been made in deciphering the molecular mechanisms of its biogenesis, including the identification of bacterial determinants and host cellular pathways involved in this process. Here I will review and discuss the most recent advances in our knowledge of Brucella intracellular pathogenesis, with an emphasis on bacterial exploitation of the host endoplasmic reticulum-associated functions, and how autophagy-related processes contribute to the bacterium's intracellular cycle.
Topics: Animals; Brucella; Host-Pathogen Interactions; Humans; Mammals; Models, Biological; Phagocytes; Vacuoles; Virulence Factors
PubMed: 25916795
DOI: 10.1111/cmi.12452 -
Cells Jun 2022Cells rely on autophagy to degrade cytosolic material and maintain homeostasis. During autophagy, content to be degraded is encapsulated in double membrane vesicles,... (Review)
Review
Cells rely on autophagy to degrade cytosolic material and maintain homeostasis. During autophagy, content to be degraded is encapsulated in double membrane vesicles, termed autophagosomes, which fuse with the yeast vacuole for degradation. This conserved cellular process requires the dynamic rearrangement of membranes. As such, the process of autophagy requires many soluble proteins that bind to membranes to restructure, tether, or facilitate lipid transfer between membranes. Here, we review the methods that have been used to investigate membrane binding by the core autophagy machinery and additional accessory proteins involved in autophagy in yeast. We also review the key experiments demonstrating how each autophagy protein was shown to interact with membranes.
Topics: Autophagosomes; Autophagy; Proteins; Saccharomyces cerevisiae; Vacuoles
PubMed: 35741004
DOI: 10.3390/cells11121876 -
Cells Aug 2022Recent studies have highlighted the importance of autophagy and particularly non-canonical autophagy in the development and progression of acute pancreatitis (a frequent... (Review)
Review
Recent studies have highlighted the importance of autophagy and particularly non-canonical autophagy in the development and progression of acute pancreatitis (a frequent disease with considerable morbidity and significant mortality). An important early event in the development of acute pancreatitis is the intrapancreatic activation of trypsinogen, (i.e., formation of trypsin) leading to the autodigestion of the organ. Another prominent phenomenon associated with the initiation of this disease is vacuolisation and specifically the formation of giant endocytic vacuoles in pancreatic acinar cells. These organelles develop in acinar cells exposed to several inducers of acute pancreatitis (including taurolithocholic acid and high concentrations of secretagogues cholecystokinin and acetylcholine). Notably, early trypsinogen activation occurs in the endocytic vacuoles. These trypsinogen-activating organelles undergo activation, long-distance trafficking, and non-canonical autophagy. In this review, we will discuss the role of autophagy in acute pancreatitis and particularly focus on the recently discovered LAP-like non-canonical autophagy (LNCA) of endocytic vacuoles.
Topics: Acute Disease; Autophagy; Humans; Pancreatitis; Trypsinogen; Vacuoles
PubMed: 36010591
DOI: 10.3390/cells11162514