Induction of high-affinity NO3– uptake in grapevine roots is an active process correlated to the expression of specific members of the NRT2 and plasma membrane H+-ATPase gene families

2014 ◽  
Vol 41 (4) ◽  
pp. 353 ◽  
Author(s):  
Youry Pii ◽  
Massimiliano Alessandrini ◽  
Katia Guardini ◽  
Anita Zamboni ◽  
Zeno Varanini
Keyword(s):  
Plasma Membrane ◽  
Expression Profile ◽  
Woody Plants ◽  
Gene Families ◽  
Vitis Vinifera L ◽  
Gene Encoding ◽  
Protein Levels ◽  
High Affinity ◽  
Atpase Gene ◽  
Hydroponically Grown

The phenomenon of NO3– induction in plant roots has been characterised both in herbaceous and woody plants. Grapevine (Vitis vinifera L.) plants, hydroponically grown, showed an increase in NO3– uptake rate in response to anion treatment for different periods in the nutrient solution after 1 week of NO3– deprivation. The expression profile of the two high-affinity NO3– transporters VvNRT2.4A and VvNRT2.4B, and the gene encoding the accessory protein VvNAR2.2 exhibits a similar trend to that of the anion uptake. The induction, also involving the increase in activity and protein levels of plasma membrane H+-ATPase, is correlated with the expression profile of two (VvHA2 and VvHA4) out of eight putative plasma membrane H+-ATPase genes identified in grapevine genome.

Presence of the iron exporter ferroportin at the plasma membrane of macrophages is enhanced by iron loading and down-regulated by hepcidin

Blood ◽  
2005 ◽  
Vol 106 (12) ◽  
pp. 3979-3984 ◽  
Author(s):  
Constance Delaby ◽  
Nathalie Pilard ◽  
Ana Sofia Gonçalves ◽  
Carole Beaumont ◽  
François Canonne-Hergaux
Keyword(s):  
Bone Marrow ◽  
Plasma Membrane ◽  
Iron Loading ◽  
Protein Levels ◽  
High Affinity ◽  
Iron Treatment ◽  
Intracellular Vesicles ◽  
Subcellular Level ◽  
Lines Of Evidence ◽  
Iron Export

Ferroportin, the only mammalian iron exporter identified to date, is highly expressed in duodenal enterocytes and in macrophages. Several lines of evidence indicate that in enterocytes the iron export mediated by ferroportin occurs and is regulated at the basolateral cell surface, where the transporter is strongly expressed. By contrast, in macrophages, ferroportin has been shown in intracellular vesicles. We used a high-affinity antibody to specify the localization of endogenous ferroportin expressed in primary culture of bone marrow–derived macrophages, in both basal and induced conditions. Our observations indicate that ferroportin is expressed in vesicular compartments that can reach the plasma membrane of macrophages. Of importance, when ferroportin expression was up-regulated through iron treatment or erythrophagocytosis, ferroportin expression was strongly enhanced at the plasma membrane of macrophages. Moreover, hepcidin dramatically reduced macrophage ferroportin protein levels. At the subcellular level, hepcidin was shown to induce rapid internalization and degradation of the macrophage iron exporter. These data are consistent with a direct iron export by ferroportin through the plasma membrane of macrophages and strongly support an efficient posttranscriptional down-regulation of ferroportin by hepcidin in these cells.

Genome-wide survey of V-ATPase genes in Drosophila reveals a conserved renal phenotype for lethal alleles

2005 ◽  
Vol 22 (2) ◽  
pp. 128-138 ◽  
Author(s):  
Adrian K. Allan ◽  
Juan Du ◽  
Shireen A. Davies ◽  
Julian A. T. Dow
Keyword(s):  
Plasma Membrane ◽  
Gene Family ◽  
Single Gene ◽  
Expression Patterns ◽  
Malpighian Tubule ◽  
Fluid Secretion ◽  
Proton Pumps ◽  
Gene Encoding ◽  
Atpase Gene ◽  
Atpase Subunits

V-ATPases are ubiquitous, vital proton pumps that play a multiplicity of roles in higher organisms. In many epithelia, they are the major energizer of cotransport processes and have been implicated in functions as diverse as fluid secretion and longevity. The first animal knockout of a V-ATPase was identified in Drosophila, and its recessive lethality demonstrated the essential nature of V-ATPases. This article surveys the entire V-ATPase gene family in Drosophila, both experimentally and in silico. Adult expression patterns of most of the genes are shown experimentally for the first time, using in situ hybridization or reporter gene expression, and these results are reconciled with published expression and microarray data. For each subunit, the single gene identified previously by microarray, as upregulated and abundant in tubules, is shown to be similarly abundant in other epithelia in which V-ATPases are known to be important; there thus appears to be a single dominant “plasma membrane” V-ATPase holoenzyme in Drosophila. This provides the most comprehensive view of V-ATPase expression yet in a multicellular organism. The transparent Malpighian tubule phenotype first identified in lethal alleles of vha55, the gene encoding the B-subunit, is shown to be general to those plasma membrane V-ATPase subunits for which lethal alleles are available, and to be caused by failure to accumulate uric acid crystals. These results coincide with the expression view of the gene family, in which 13 of the genes are specialized for epithelial roles, whereas others have spatially or temporally restricted patterns of expression.

scholarly journals Ponticulin is the major high affinity link between the plasma membrane and the cortical actin network in Dictyostelium.

1994 ◽  
Vol 126 (6) ◽  
pp. 1433-1444 ◽  
Author(s):  
A L Hitt ◽  
J H Hartwig ◽  
E J Luna
Keyword(s):  
Plasma Membrane ◽  
Cell Shape ◽  
Plasma Membranes ◽  
Axenic Culture ◽  
Actin Binding ◽  
Growth Media ◽  
Cortical Actin ◽  
Gene Encoding ◽  
High Affinity

Interactions between the plasma membrane and underlying actin-based cortex have been implicated in membrane organization and stability, the control of cell shape, and various motile processes. To ascertain the function of high affinity actin-membrane associations, we have disrupted by homologous recombination the gene encoding ponticulin, the major high affinity actin-membrane link in Dictyostelium discoideum amoebae. Cells lacking detectable amounts of ponticulin message and protein also are deficient in high affinity actin-membrane binding by several criteria. First, only 10-13% as much endogenous actin cosediments through sucrose and crude plasma membranes from ponticulin-minus cells, as compared with membranes from the parental strain. Second, purified plasma membranes exhibit little or no binding or nucleation of exogenous actin in vitro. Finally, only 10-30% as much endogenous actin partitions with plasma membranes from ponticulin-minus cells after these cells are mechanically unroofed with polylysine-coated coverslips. The loss of the cell's major actin-binding membrane protein appears to be surprisingly benign under laboratory conditions. Ponticulin-minus cells grow normally in axenic culture and pinocytose FITC-dextran at the same rate as do parental cells. The rate of phagocytosis of particles by ponticulin-minus cells in growth media also is unaffected. By contrast, after initiation of development, cells lacking ponticulin aggregate faster than the parental cells. Subsequent morphogenesis proceeds asynchronously, but viable spores can form. These results indicate that ponticulin is not required for cellular translocation, but apparently plays a role in cell patterning during development.

scholarly journals Identification of intestinal cells responsive to calcitriol (1,25-dihydroxycholecalciferol)

1985 ◽  
Vol 225 (1) ◽  
pp. 127-133 ◽  
Author(s):  
M W Smith ◽  
M E Bruns ◽  
E D M Lawson
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Quantitative Description ◽  
Intestinal Cells ◽  
Protein Levels ◽  
High Affinity ◽  
Hormone Injection ◽  
Crypt Cells

The location of intestinal cells taken from the base of the crypt to the tip of the villus responsive to calcitriol (1,25-dihydroxycholecalciferol) and the distribution of [3H]calcitriol within the intestinal epithelium has been determined in vitamin D-deficient rats. The calcitriol responses examined were CaBP (Ca2+-binding protein) levels as measured by immunodiffusion and alkaline phosphatase levels as determined cytochemically. Calcitriol had no effect on villus structure or on enterocyte kinetics. This made it possible to compare levels of CaBP and alkaline phosphatase activity in enterocytes at different ages in rats at known times after hormone injection. Cells from both the crypt and villus synthesized CaBP in response to calcitriol. Alkaline phosphatase activity was not detectable in crypt cells, although a pool of precursor was produced in these cells in response to calcitriol. Enzyme activity was increased in all villus cells in response to calcitriol, but the quantitative description of this effect was very different from that found for calcitriol effects on CaBP synthesis. Calcitriol injected into vitamin D-deficient rats was detected, within 2h, in all cells of the crypt and villus. Most of the binding was to sites having a high affinity for the injected hormone.

Plasma Membrane Calcium ATPase Gene Expression in Bovine Lens Epithelium

2000 ◽  
Vol 32 (2-3) ◽  
pp. 100-105 ◽  
Author(s):  
Lijun Bian ◽  
Junwen Zeng ◽  
Douglas Borchman ◽  
Christopher A. Paterson
Keyword(s):  
Gene Expression ◽  
Plasma Membrane ◽  
Calcium Atpase ◽  
Lens Epithelium ◽  
Plasma Membrane Calcium Atpase ◽  
Bovine Lens ◽  
Atpase Gene
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