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Dušková M, Cmunt D, Papoušková K, Masaryk J, Sychrová H. Minority potassium-uptake system Trk2 has a crucial role in yeast survival of glucose-induced cell death. MICROBIOLOGY-SGM 2021; 167. [PMID: 34170815 DOI: 10.1099/mic.0.001065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The existence of programmed cell death in Saccharomyces cerevisiae has been reported for many years. Glucose induces the death of S. cerevisiae in the absence of additional nutrients within a few hours, and the absence of active potassium uptake makes cells highly sensitive to this process. S. cerevisiae cells possess two transporters, Trk1 and Trk2, which ensure a high intracellular concentration of potassium, necessary for many physiological processes. Trk1 is the major system responsible for potassium acquisition in growing and dividing cells. The contribution of Trk2 to potassium uptake in growing cells is almost negligible, but Trk2 becomes crucial for stationary cells for their survival of some stresses, e.g. anhydrobiosis. As a new finding, we show that both Trk systems contribute to the relative thermotolerance of S. cerevisiae BY4741. Our results also demonstrate that Trk2 is much more important for the cell survival of glucose-induced cell death than Trk1, and that stationary cells deficient in active potassium uptake lose their ATP stocks more rapidly than cells with functional Trk systems. This is probably due to the upregulated activity of plasma-membrane Pma1 H+-ATPase, and consequently, it is the reason why these cells die earlier than cells with functional active potassium uptake.
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Affiliation(s)
- Michala Dušková
- Laboratory of Membrane Transport, Institute of Physiology, Czech Academy of Sciences, Prague 4, Czech Republic
| | - Denis Cmunt
- Laboratory of Membrane Transport, Institute of Physiology, Czech Academy of Sciences, Prague 4, Czech Republic.,Present address: Dept. Oncology, Ludwig Institute for Cancer Research, University of Lausanne, Lausanne, Switzerland
| | - Klára Papoušková
- Laboratory of Membrane Transport, Institute of Physiology, Czech Academy of Sciences, Prague 4, Czech Republic
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Rangarajan N, Kapoor I, Li S, Drossopoulos P, White KK, Madden VJ, Dohlman HG. Potassium starvation induces autophagy in yeast. J Biol Chem 2020; 295:14189-14202. [PMID: 32788210 DOI: 10.1074/jbc.ra120.014687] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/02/2020] [Indexed: 01/04/2023] Open
Abstract
Autophagy is a conserved process that recycles cellular contents to promote survival. Although nitrogen limitation is the canonical inducer of autophagy, recent studies have revealed several other nutrients important to this process. In this study, we used a quantitative, high-throughput assay to identify potassium starvation as a new and potent inducer of autophagy in the yeast Saccharomyces cerevisiae We found that potassium-dependent autophagy requires the core pathway kinases Atg1, Atg5, and Vps34, and other components of the phosphatidylinositol 3-kinase complex. Transmission EM revealed abundant autophagosome formation in response to both stimuli. RNA-Seq indicated distinct transcriptional responses: nitrogen affects transport of ions such as copper, whereas potassium targets the organization of other cellular components. Thus, nitrogen and potassium share the ability to influence molecular supply and demand but do so in different ways. Both inputs promote catabolism through bulk autophagy, but result in distinct mechanisms of cellular remodeling and synthesis.
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Affiliation(s)
- Nambirajan Rangarajan
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ishani Kapoor
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Shuang Li
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Peter Drossopoulos
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Kristen K White
- Microscopy Services Laboratory, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Victoria J Madden
- Microscopy Services Laboratory, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Henrik G Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Cytosolic Acidification Is the First Transduction Signal of Lactoferrin-induced Regulated Cell Death Pathway. Int J Mol Sci 2019; 20:ijms20235838. [PMID: 31757076 PMCID: PMC6928705 DOI: 10.3390/ijms20235838] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 01/04/2023] Open
Abstract
In yeast, we reported the critical role of K+-efflux for the progress of the regulated cell death (RCD) induced by human lactoferrin (hLf), an antimicrobial protein of the innate immune system that blocks Pma1p H+-ATPase. In the present study, the K+ channel Tok1p was identified as the K+ channel-mediating K+-efflux, as indicated by the protective effect of extracellular K+ (30 mM), K+-channel blockers, and the greater hLf-resistance of TOK1-disrupted strains. K+-depletion was necessary but not sufficient to induce RCD as inferred from the effects of valinomycin, NH4Cl or nigericin which released a percentage of K+ similar to that released by lactoferrin without affecting cell viability. Cytosolic pH of hLf-treated cells decreased transiently (0.3 pH units) and its inhibition prevented the RCD process, indicating that cytosolic acidification was a necessary and sufficient triggering signal. The blocking effect of lactoferrin on Pma1p H+-ATPase caused a transitory decrease of cytosolic pH, and the subsequent membrane depolarization activated the voltage-gated K+ channel, Tok1p, allowing an electrogenic K+-efflux. These ionic events, cytosolic accumulation of H+ followed by K+-efflux, constituted the initiating signals of this mitochondria-mediated cell death. These findings suggest, for the first time, the existence of an ionic signaling pathway in RCD.
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Sasikumar AN, Killilea DW, Kennedy BK, Brem RB. Potassium restriction boosts vacuolar acidity and extends lifespan in yeast. Exp Gerontol 2019; 120:101-106. [PMID: 30742903 DOI: 10.1016/j.exger.2019.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/15/2019] [Accepted: 02/01/2019] [Indexed: 12/23/2022]
Abstract
Lysosome function is compromised during aging and in many disease states. Interventions that promote lysosomal activity and acidification are thus of prime interest as treatments for longevity and health. Intracellular pH can be controlled by the exchange of protons for inorganic ions, and in cells from microbes to man, when potassium is restricted in the growth medium, the cytoplasm becomes acidified. Here we use a yeast model to show that potassium limited-cells exhibit hallmarks of increased acidity in the vacuole, the analog of the lysosome, and live long by a mechanism that requires the vacuolar machinery. The emerging picture is one in which potassium restriction shores up vacuolar acidity and function, conferring health benefits early in life and extending viability into old age. Against the backdrop of well-studied protein and carbohydrate restrictions that extend lifespan and healthspan, our work establishes a novel pro-longevity paradigm of inorganic nutrient limitation.
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Affiliation(s)
- Arjun N Sasikumar
- Buck Institute for Research on Aging, Novato, CA, United States of America
| | - David W Killilea
- Nutrition & Metabolism Center and Elemental Analysis Facility, Children's Hospital Oakland Research Institute, Oakland, CA, United States of America
| | - Brian K Kennedy
- Buck Institute for Research on Aging, Novato, CA, United States of America; Departments of Biochemistry and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Rachel B Brem
- Buck Institute for Research on Aging, Novato, CA, United States of America; Department of Plant and Microbial Biology, UC Berkeley, Berkeley, CA, United States of America.
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Demidchik V. ROS-Activated Ion Channels in Plants: Biophysical Characteristics, Physiological Functions and Molecular Nature. Int J Mol Sci 2018; 19:E1263. [PMID: 29690632 PMCID: PMC5979493 DOI: 10.3390/ijms19041263] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 12/16/2022] Open
Abstract
Ion channels activated by reactive oxygen species (ROS) have been found in the plasma membrane of charophyte Nitella flixilis, dicotyledon Arabidopsis thaliana, Pyrus pyrifolia and Pisum sativum, and the monocotyledon Lilium longiflorum. Their activities have been reported in charophyte giant internodes, root trichoblasts and atrichoblasts, pollen tubes, and guard cells. Hydrogen peroxide and hydroxyl radicals are major activating species for these channels. Plant ROS-activated ion channels include inwardly-rectifying, outwardly-rectifying, and voltage-independent groups. The inwardly-rectifying ROS-activated ion channels mediate Ca2+-influx for growth and development in roots and pollen tubes. The outwardly-rectifying group facilitates K⁺ efflux for the regulation of osmotic pressure in guard cells, induction of programmed cell death, and autophagy in roots. The voltage-independent group mediates both Ca2+ influx and K⁺ efflux. Most studies suggest that ROS-activated channels are non-selective cation channels. Single-channel studies revealed activation of 14.5-pS Ca2+ influx and 16-pS K⁺ efflux unitary conductances in response to ROS. The molecular nature of ROS-activated Ca2+ influx channels remains poorly understood, although annexins and cyclic nucleotide-gated channels have been proposed for this role. The ROS-activated K⁺ channels have recently been identified as products of Stellar K⁺ Outward Rectifier (SKOR) and Guard cell Outwardly Rectifying K⁺ channel (GORK) genes.
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Affiliation(s)
- Vadim Demidchik
- Department of Horticulture, School of Food Science and Engineering, Foshan University, Foshan 528000, China.
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Avenue, 220030 Minsk, Belarus.
- Russian Academy of Sciences, Komarov Botanical Institute, 2 Professora Popova Street, 197376 St. Petersburg, Russia.
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Simontacchi M, Galatro A, Ramos-Artuso F, Santa-María GE. Plant Survival in a Changing Environment: The Role of Nitric Oxide in Plant Responses to Abiotic Stress. FRONTIERS IN PLANT SCIENCE 2015; 6:977. [PMID: 26617619 PMCID: PMC4637419 DOI: 10.3389/fpls.2015.00977] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/26/2015] [Indexed: 05/20/2023]
Abstract
Nitric oxide in plants may originate endogenously or come from surrounding atmosphere and soil. Interestingly, this gaseous free radical is far from having a constant level and varies greatly among tissues depending on a given plant's ontogeny and environmental fluctuations. Proper plant growth, vegetative development, and reproduction require the integration of plant hormonal activity with the antioxidant network, as well as the maintenance of concentration of reactive oxygen and nitrogen species within a narrow range. Plants are frequently faced with abiotic stress conditions such as low nutrient availability, salinity, drought, high ultraviolet (UV) radiation and extreme temperatures, which can influence developmental processes and lead to growth restriction making adaptive responses the plant's priority. The ability of plants to respond and survive under environmental-stress conditions involves sensing and signaling events where nitric oxide becomes a critical component mediating hormonal actions, interacting with reactive oxygen species, and modulating gene expression and protein activity. This review focuses on the current knowledge of the role of nitric oxide in adaptive plant responses to some specific abiotic stress conditions, particularly low mineral nutrient supply, drought, salinity and high UV-B radiation.
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Affiliation(s)
- Marcela Simontacchi
- Instituto de Fisiología Vegetal, Universidad Nacional de La Plata–Consejo Nacional de Investigaciones Científicas y TécnicasLa Plata, Argentina
| | - Andrea Galatro
- Physical Chemistry – Institute for Biochemistry and Molecular Medicine, Faculty of Pharmacy and Biochemistry, University of Buenos Aires–Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Facundo Ramos-Artuso
- Instituto de Fisiología Vegetal, Universidad Nacional de La Plata–Consejo Nacional de Investigaciones Científicas y TécnicasLa Plata, Argentina
| | - Guillermo E. Santa-María
- Instituto Tecnológico Chascomús, Consejo Nacional de Investigaciones Científicas y Técnicas–Universidad Nacional de San MartínChascomús, Argentina
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Gelis S, Curto M, Valledor L, González A, Ariño J, Jorrín J, Ramos J. Adaptation to potassium starvation of wild-type and K(+)-transport mutant (trk1,2) of Saccharomyces cerevisiae: 2-dimensional gel electrophoresis-based proteomic approach. Microbiologyopen 2012; 1:182-93. [PMID: 22950024 PMCID: PMC3426419 DOI: 10.1002/mbo3.23] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 03/29/2012] [Accepted: 05/03/2012] [Indexed: 01/20/2023] Open
Abstract
Saccharomyces cerevisiae wild-type (BY4741) and the corresponding mutant lacking the plasma membrane main potassium uptake systems (trk1,trk2) were used to analyze the consequences of K(+) starvation following a proteomic approach. In order to trigger high-affinity mode of potassium transport, cells were transferred to potassium-free medium. Protein profile was followed by two-dimensional (2-D) gels in samples taken at 0, 30, 60, 120, 180, and 300 min during starvation. We observed a general decrease of protein content during starvation that was especially drastic in the mutant strain as it was the case of an important number of proteins involved in glycolysis. On the contrary, we identified proteins related to stress response and alternative energetic metabolism that remained clearly present. Neural network-based analysis indicated that wild type was able to adapt much faster than the mutant to the stress process. We conclude that complete potassium starvation is a stressful process for yeast cells, especially for potassium transport mutants, and we propose that less stressing conditions should be used in order to study potassium homeostasis in yeast.
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Affiliation(s)
- Samuel Gelis
- Department of Microbiology, University of CórdobaCórdoba, Spain
| | - Miguel Curto
- Department of Biochemistry and Molecular Biology, Agricultural and Plant Biochemistry and Proteomics Research Group, University of CórdobaCórdoba, Spain
| | - Luis Valledor
- Molecular Systems Biology, University of ViennaVienna, Austria
| | - Asier González
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de BarcelonaBellaterra 08193, Barcelona, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de BarcelonaBellaterra 08193, Barcelona, Spain
| | - Jesús Jorrín
- Department of Biochemistry and Molecular Biology, Agricultural and Plant Biochemistry and Proteomics Research Group, University of CórdobaCórdoba, Spain
| | - José Ramos
- Department of Microbiology, University of CórdobaCórdoba, Spain
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