A5059253020- Photosynthetic Processes and Mechanisms
- Plant nutrient uptake and metabolism
- ATP Synthase and ATPases Research
- Plant Stress Responses and Tolerance
- Plant Molecular Biology Research
- Plant Reproductive Biology
- Magnetic and Electromagnetic Effects
- Lipid Membrane Structure and Behavior
- Plant Micronutrient Interactions and Effects
- Fungal and yeast genetics research
- Microbial Metabolites in Food Biotechnology
- Electrochemical sensors and biosensors
- Legume Nitrogen Fixing Symbiosis
- Seed Germination and Physiology
- Cellular transport and secretion
- Neonatal Health and Biochemistry
- Nitrogen and Sulfur Effects on Brassica
- Endoplasmic Reticulum Stress and Disease
- Plant Genetic and Mutation Studies
- Aluminum toxicity and tolerance in plants and animals
- Enzyme Structure and Function
- Phytase and its Applications
- Molecular Sensors and Ion Detection
- Mitochondrial Function and Pathology
- Ion Transport and Channel Regulation
University of Maryland, College Park
2011-2024
Zhejiang University
2018
University of Minnesota
2004-2008
Noble Research Institute
2008
Baylor College of Medicine
2008
United States Department of Agriculture
2008
Texas A&M University
2008
University of Nevada, Reno
2008
Charles University
2006
Czech Academy of Sciences, Institute of Experimental Botany
2004-2006
Abstract Uptake and translocation of cationic nutrients play essential roles in physiological processes including plant growth, nutrition, signal transduction, development. Approximately 5% the Arabidopsis genome appears to encode membrane transport proteins. These proteins are classified 46 unique families containing approximately 880 members. In addition, several hundred putative transporters have not yet been assigned families. this paper, we analyzed phylogenetic relationships over 150...
In this paper, two primary active transport systems (H/sup +/ -ATPases) in plant cells are examined using membrane vesicles as a simple experimental tool. One electrogenic, H/sup -translocating ATPase is vanadate-sensitive and associated with the plasma membrane. Another ATPases anion-sensitive, localized on tonoplast (and perhaps other membranes). According to working model, tonoplast-type -ATPases detectable inside-out right-side-out vesicles. The direction of pumping into these would be...
The circulation of ions across biological membranes is a fundamental process cellular energetics ([Harold, 1986][1]). Indeed, ion currents play the key role in energy capture during respiration and photosynthesis. They mediate interconversion chemical, osmotic, electrical forms
Karin Schumacher, Dionne Vafeados, Melissa McCarthy, Heven Sze, Thea Wilkins, and Joanne Chory Howard Hughes Medical Institute Plant Biology Laboratory, The Salk for Biological Studies, La Jolla, California 92037 USA; Department of Cell Molecular Genetics, University Maryland, College Park, Maryland 20742 Agronomy Range Science, California, Davis, 95616 USA
In plant cells, transient changes in cytoplasmicCa2+ levels can modulate numerous developmental processes.Ca2+ is accumulated the vacuole via a H+/Ca2+ antiport system that energized by tonoplast H+pumping ATPase.Inositol l.,4,5-trisphosphate (InsP3), but not inositol 1,4-bisphosphate, myo-inositol l-phosphate, or fructose 2,6-bisphosphate, caused reduction of Ca2+ vesicles.The decrease was dependent on InsP3 concentration ( K , apparent = 0.6 p ~) .The InsP3-induced release blocked ea2+...
All organisms have evolved strategies to regulate ion and pH homeostasis in response developmental environmental cues. One strategy is mediated by monovalent cation-proton antiporters (CPA) that are classified two superfamilies. Many CPA1 genes from bacteria, fungi, metazoa, plants been functionally characterized; though roles of plant CPA2 encoding K(+)-efflux antiporter (KEA) cation/H(+) exchanger (CHX) families largely unknown. Phylogenetic analysis showed three clades the Na(+)-H(+)...
Abstract Male fertility depends on the proper development of male gametophyte, successful pollen germination, tube growth, and delivery sperm cells to ovule. Previous studies have shown that nutrients like boron, ion gradients or currents Ca2+, H+, K+ are critical for growth. However, molecular identities transporters mediating these fluxes mostly unknown. As a first step integrate transport with function, genome-wide analysis transporter genes expressed in gametophyte at four developmental...
Higher plant cells have one or more vacuoles important for maintaining cell turgor and the transport storage of ions metabolites.One driving force solute across vacuolar membrane (tonoplast) is provided by an ATP-dependent electrogenic H+ pump.The tonoplast H+-pumping ATPase from oat roots has been solubilized with Triton X-100 purified 16-fold Sepharose 4B chromatography.The partially enzyme was sensitive to same inhibitors (N-ethylmaleimide, N,N'-dicyclohexylcarbodiimide (DCCD),...
Abstract Flowering plant reproduction requires precise delivery of the sperm cells to ovule by a pollen tube. Guidance signals from female are being identified; however, how responds those cues is largely unknown. Here, we show that two predicted cation/proton exchangers (CHX) in Arabidopsis thaliana, CHX21 and CHX23, essential for tube guidance. Male fertility was unchanged single chx21 or chx23 mutants. However, impaired double mutant pollen. Wild-type pistils pollinated with limited...
Two types of ATP-dependent calcium (Ca2+) transport systems were detected in sealed microsomal vesicles from oat roots. Approximately 80% the total Ca2+ uptake was associated with 1.11 grams per cubic centimeter and insensitive to vanadate or azide, but inhibited by NO3−. The remaining 20% vanadate-sensitive mostly endoplasmic reticulum, as activity comigrated an reticulum marker (antimycin A-insensitive NADH cytochrome c reductase), which shifted 1.20 Mg2+. Like tonoplast H+-ATPase...
Abstract Rapid stomatal closure is essential for water conservation in plants and thus critical survival under deficiency. To close stomata rapidly, guard cells reduce their volume by converting a large central vacuole into highly convoluted structure. However, the molecular mechanisms underlying this change are poorly understood. In study, we used pH-indicator dyes to demonstrate that vacuolar convolution accompanied acidification of fava bean (Vicia faba) during abscisic acid (ABA)–induced...
Abstract Plants can grow in soils containing highly variable amounts of mineral nutrients, like Ca2+ and Mn2+, though the mechanisms adaptation are poorly understood. Here, we report first genetic study to determine vivo functions a pump plants. Homozygous mutants Arabidopsis harboring T-DNA disruption ECA1 showed 4-fold reduction endoplasmic reticulum-type calcium activity. Surprisingly, phenotype mutant plants was indistinguishable from wild type when grown on standard nutrient medium 1.5...
The magnitude and duration of a cytosolic Ca 2+ release can potentially be altered by changing the rate efflux. In plant cells, efflux from cytoplasm is mediated H + /Ca -antiporters two types -ATPases. ACA2 was recently identified as calmodulin-regulated -pump located in endoplasmic reticulum. Here, we show that phosphorylation its N-terminal regulatory domain -dependent protein kinase (CDPK isoform CPK1), inhibits both basal activity (≈10%) calmodulin stimulation (≈75%), shown -transport...
A combined bioinformatic and experimental approach is being used to uncover the functions of a novel family cation/H(+) exchanger (CHX) genes in plants using Arabidopsis as model. The predicted protein (85-95 kD) 28 AtCHX after revision consists an amino-terminal domain with 10 12 transmembrane spans (approximately 440 residues) hydrophilic approximately 360 residues at carboxyl end, which proposed have regulatory roles. hydrophobic, but not hydrophilic, plant CHX remarkably similar...
To study transporters involved in regulating intracellular Ca2+, we isolated a full-length cDNA encoding Ca2+-ATPase from model plant, Arabidopsis, and named it ACA2 (Arabidopsis Ca2+-ATPase, isoform 2). ACA2p is most similar to "plasma membrane-type" but smaller (110 kDa), contains unique N-terminal domain, missing long C-terminal calmodulin-binding regulatory domain. In addition, localized an endomembrane system not the plasma membrane, as shown by aqueous-two phase fractionation of...
To understand the structure, role, and regulation of individual Ca 2+ pumps in plants, we have used yeast as a heterologous expression system to test function gene from Arabidopsis thaliana (ECA1). ECA1 encoded 116-kDa polypeptide that has all conserved domains common P-type (EC 3.6.1.38 ). The amino acid sequence shared more identity with sarcoplasmic/endoplasmic reticulum (53%) than plasma membrane (32%) pumps. Yeast mutants defective Golgi pump ( pmr1 ) or both vacuolar pmc1 cnb1 were...
Calcium (Ca2+) is sequestered into vacuoles of oat root cells through a H+/Ca2+ antiport system that driven by the proton-motive force tonoplast H+-translocating ATPase. The has been characterized directly imposing pH gradient in tonoplast-enriched vesicles. was imposed diluting K+-loaded vesicles K+-free medium. Nigericin induced K+/H+ exchange resulting 2 (acid inside). capable driving 45Ca2+ accumulation. Ca2+ uptake tightly coupled to H+ loss as increasing levels progressively dissipated...
Abstract Acidification of intracellular compartments by the vacuolar-type H+-ATPases (VHA) is known to energize ion and metabolite transport, though cellular processes influenced this activity are poorly understood. At least 26 VHA genes encode 12 subunits V1Vo-ATPase complex in Arabidopsis, how expression, assembly, pump integrated into signaling networks that govern growth adaptation largely unknown. The role multiple VHA-c encoding 16-kD subunit membrane Vo sector was investigated....
A H(+)-translocating inorganic pyrophosphatase (H(+)-PPase) was associated with low density membranes enriched in tonoplast vesicles of oat roots. The H(+)-PPase catalyzed the electrogenic transport H(+) into vesicles, generating a pH gradient, inside acid (quinacrine fluorescence quenching), and membrane potential, positive (Oxonol V quenching). Transport activity dependent on cations selectivity sequence Rb(+) = K(+) > Cs(+); but it inhibited by Na(+) or Li(+). Maximum rates required at...
H+-pumping ATPases were detected in microsomal vesicles of oat (Avena sativa L. var Lang) roots using [14C]methylamine distribution or quinacrine fluorescent quenching. Methylamine (MeA) accumulation into and quench specifically dependent on Mg,ATP. Both activities reflected formation a proton gradient (ΔpH) (acid inside) as carbonyl cyanide m-chlorophenylhydrazone, nigericin (in the presence K+), gramicidin decreased MeA uptake increased fluorescence. The properties H+ pumping measured by...