Membrane transport: mechanisms and processes from organelles to whole plants

2001 ◽  
Vol 28 (7) ◽  
pp. 519 ◽  
Author(s):  
F. Andrew Smith
Keyword(s):  
Plasma Membrane ◽  
Driving Force ◽  
Inorganic Phosphate ◽  
Plant Cells ◽  
Transport Mechanisms ◽  
Physiological Control ◽  
Physiological Level ◽  
Pi Transport ◽  
Cytoplasmic Acidification ◽  
Whole Plants

Inorganic phosphate (Pi) uptake systems across the plasma membrane of plant cells have been extensively investigated. Physiological studies have established that Pi is transported into plant cells via co-transport with H+ , and in some plants with Na + , using the driving force provided by the electrogenic H + pump in the plasma membrane. Molecular studies have identified many genes for Pi transporters and are providing insights into the mechanisms of genetic control of Pi transport. There still remain, however, questions as to how Pi uptake systems are regulated at the physiological level. We have found that Pi uptake induces cytoplasmic acidification, and, conversely, that inducing cytoplasmic acidification causes the cytoplasmic Pi concentration to decrease. Both of these responses affect the operation of the H + -pump. These phenomena are discussed in relation to a possible mechanism for the physiological control of Pi uptake by plant cells.

Physiological control of phosphate uptake and phosphate homeostasis in plant cells

2001 ◽  
Vol 28 (7) ◽  
pp. 655 ◽  
Author(s):  
Tetsuro Mimura
Keyword(s):  
Plasma Membrane ◽  
Driving Force ◽  
Inorganic Phosphate ◽  
Phosphate Uptake ◽  
Plant Cells ◽  
Phosphate Homeostasis ◽  
Physiological Control ◽  
Physiological Level ◽  
Pi Transport ◽  
Cytoplasmic Acidification

Inorganic phosphate (Pi) uptake systems across the plasma membrane of plant cells have been extensively investigated. Physiological studies have established that Pi is transported into plant cells via co-transport with H+ , and in some plants with Na + , using the driving force provided by the electrogenic H + pump in the plasma membrane. Molecular studies have identified many genes for Pi transporters and are providing insights into the mechanisms of genetic control of Pi transport. There still remain, however, questions as to how Pi uptake systems are regulated at the physiological level. We have found that Pi uptake induces cytoplasmic acidification, and, conversely, that inducing cytoplasmic acidification causes the cytoplasmic Pi concentration to decrease. Both of these responses affect the operation of the H + -pump. These phenomena are discussed in relation to a possible mechanism for the physiological control of Pi uptake by plant cells.

Enrichment of vitronectin- and fibronectin-like proteins in NaCI-adapted plant cells and evidence for their involvement in plasma membrane-cell wall adhesion

1993 ◽  
Vol 3 (5) ◽  
pp. 637-646 ◽  
Author(s):  
Jian-Kang Zhu ◽  
Jun Shi ◽  
Utpal Singh ◽  
Sarah E. Wyatt ◽  
Ray A. Bressan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Plant Cells ◽  
Membrane Cell

scholarly journals Fig mosaic emaravirus p4 protein is involved in cell-to-cell movement

2013 ◽  
Vol 94 (3) ◽  
pp. 682-686 ◽  
Author(s):  
Kazuya Ishikawa ◽  
Kensaku Maejima ◽  
Ken Komatsu ◽  
Osamu Netsu ◽  
Takuya Keima ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Laser Scanning ◽  
Movement Protein ◽  
Rna Virus ◽  
Cell Movement ◽  
Plant Cells ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Series Of Experiments ◽  
Fig Mosaic Virus

Fig mosaic virus (FMV), a member of the newly formed genus Emaravirus, is a segmented negative-strand RNA virus. Each of the six genomic FMV segments contains a single ORF: that of RNA4 encodes the protein p4. FMV-p4 is presumed to be the movement protein (MP) of the virus; however, direct experimental evidence for this is lacking. We assessed the intercellular distribution of FMV-p4 in plant cells by confocal laser scanning microscopy and we found that FMV-p4 was localized to plasmodesmata and to the plasma membrane accompanied by tubule-like structures. A series of experiments designed to examine the movement functions revealed that FMV-p4 has the capacity to complement viral cell-to-cell movement, prompt GFP diffusion between cells, and spread by itself to neighbouring cells. Altogether, our findings demonstrated that FMV-p4 shares several properties with other viral MPs and plays an important role in cell-to-cell movement.

scholarly journals Effects of cytoplasmic acidification on clathrin lattice morphology.

1989 ◽  
Vol 108 (2) ◽  
pp. 401-411 ◽  
Author(s):  
J Heuser
Keyword(s):  
Plasma Membrane ◽  
Cultured Cells ◽  
Membrane Receptors ◽  
The Other ◽  
Culture Dish ◽  
Initial Curvature ◽  
Internal Ph ◽  
Cytoplasmic Acidification

Reducing the internal pH of cultured cells by several different protocols that block endocytosis is found to alter the structure of clathrin lattices on the inside of the plasma membrane. Lattices curve inward until they become almost spherical yet remain stubbornly attached to the membrane. Also, the lattices bloom empty "microcages" of clathrin around their edges. Correspondingly, broken-open cells bathed in acidified media demonstrate similar changes in clathrin lattices. Acidification accentuates the normal tendency of lattices to round up in vitro and also stimulates them to nucleate microcage formation from pure solutions of clathrin. On the other hand, several conditions that also inhibit endocytosis have been found to create, instead of unusually curved clathrin lattices with extraneous microcages, a preponderance of unusually flat lattices. These treatments include pH-"clamping" cells at neutrality with nigericin, swelling cells with hypotonic media, and sticking cells to the surface of a culture dish with soluble polylysine. Again, the unusually flat lattices in such cells display a tendency to round up and to nucleate clathrin microcage formation during subsequent in vitro acidification. This indicates that regardless of the initial curvature of clathrin lattices, they all display an ability to grow and increase their curvature in vitro, and this is enhanced by lowering ambient pH. Possibly, clathrin lattice growth and curvature in vivo may also be stimulated by a local drop in pH around clusters of membrane receptors.

Ion Channels in the Plasma Membrane of Plant Cells

1992 ◽  
pp. 225-236
Author(s):  
B. R. Terry ◽  
S. D. Tyerman ◽  
G. P. Findlay
Keyword(s):  
Plasma Membrane ◽  
Ion Channels ◽  
Plant Cells

Characterization of two Mg2+transporters in sealed plasma membrane vesicles from rat liver

1998 ◽  
Vol 275 (4) ◽  
pp. C995-C1008 ◽  
Author(s):  
Christie Cefaratti ◽  
Andrea Romani ◽  
Antonio Scarpa
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Intracellular Signaling ◽  
Mammalian Cells ◽  
Plasma Membranes ◽  
Membrane Vesicles ◽  
Channel Blockers ◽  
Transport Mechanisms ◽  
Plasma Membrane Vesicles ◽  
New Information

The plasma membrane of mammalian cells possesses rapid Mg2+ transport mechanisms. The identity of Mg2+ transporters is unknown, and so are their properties. In this study, Mg2+ transporters were characterized using a biochemically and morphologically standardized preparation of sealed rat liver plasma membranes (LPM) whose intravesicular content could be set and controlled. The system has the advantages that it is not regulated by intracellular signaling machinery and that the intravesicular ion milieu can be designed. The results indicate that 1) LPM retain trapped intravesicular total Mg2+with negligible leak; 2) the addition of Na+ or Ca2+ induces a concentration- and temperature-dependent efflux corresponding to 30–50% of the intravesicular Mg2+; 3) the rate of flux is very rapid (137.6 and 86.8 nmol total Mg2+ ⋅ μm−2 ⋅ min−1after Na+ and Ca2+ addition, respectively); 4) coaddition of maximal concentrations of Na+ and Ca2+ induces an additive Mg2+ efflux; 5) both Na+- and Ca2+-stimulated Mg2+ effluxes are inhibited by amiloride, imipramine, or quinidine but not by vanadate or Ca2+ channel blockers; 6) extracellular Na+ or Ca2+ can stimulate Mg2+ efflux in the absence of Mg2+ gradients; and 7) Mg2+ uptake occurs in LPM loaded with Na+ but not with Ca2+, thus indicating that Na+/Mg2+but not Ca2+/Mg2+exchange is reversible. These data are consistent with the operation of two distinct Mg2+ transport mechanisms and provide new information on rates of Mg2+ transport, specificity of the cotransported ions, and reversibility of the transport.

scholarly journals Synthesis of radioiodinated probes to evaluate the biodistribution of a potent TRPC3 inhibitor

MedChemComm ◽  
2016 ◽  
Vol 7 (5) ◽  
pp. 1003-1006 ◽  
Author(s):  
Masayori Hagimori ◽  
Takahiro Murakami ◽  
Kinue Shimizu ◽  
Motohiro Nishida ◽  
Takashi Ohshima ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Driving Force ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Transient Receptor Potential Canonical ◽  
Transient Receptor ◽  
Trpc3 Channel

The transient receptor potential canonical 3 (TRPC3) channel is a member of the TRPC family that contributes to the entry of Ca2+through the plasma membrane or modulates the driving force for Ca2+entry channels.

Influence of bafilomycin A1on pHi responses in cultured rabbit nonpigmented ciliary epithelium

1997 ◽  
Vol 273 (5) ◽  
pp. C1700-C1706 ◽  
Author(s):  
Qiang Wu ◽  
Nicholas A. Delamere
Keyword(s):  
Plasma Membrane ◽  
Disulfonic Acid ◽  
Ciliary Epithelium ◽  
Free Medium ◽  
Acid Base Balance ◽  
Carbonyl Cyanide ◽  
Base Balance ◽  
Rich Solution ◽  
Cytoplasmic Acidification ◽  
Nonpigmented Ciliary Epithelium

Aqueous humor secretion is in part linked to [Formula: see text]transport by nonpigmented ciliary epithelium (NPE) cells. During this process, the cells must maintain stable cytoplasmic pH (pHi). Because a recent report suggests that NPE cells have a plasma membrane-localized vacuolar H+-ATPase, the present study was conducted to examine whether vacuolar H+-ATPase contributes to pHi regulation in a rabbit NPE cell line. Western blot confirmed vacuolar H+-ATPase expression as judged by H+-ATPase 31-kDa immunoreactive polypeptide in both cultured NPE and native ciliary epithelium. pHi was measured using 2′,7′-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF). Exposing cultured NPE to K+-rich solution caused a pHi increase we interpret as depolarization-induced alkalinization. Alkalinization was also caused by ouabain or BaCl2. Bafilomycin A1 (0.1 μM; an inhibitor of vacuolar H+-ATPase) inhibited the pHi increase caused by high K+. The pHi increase was also inhibited by angiotensin II and the metabolic uncoupler carbonyl cyanide m-chlorophenylhydazone but not by ZnCl2, 4-acetamido-4′-isothiocyanostilbene-2,2′-disulfonic acid (SITS), 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS), omeprazole, low-Cl−medium, [Formula: see text]-free medium, or Na+-free medium. Bafilomycin A1 slowed the pHi increase after an NH4Cl (10 mM) prepulse. However, no detectable pHi change was observed in cells exposed to bafilomycin A1 under control conditions. These studies suggest that vacuolar H+-ATPase is activated by cytoplasmic acidification and by reduction of the proton electrochemical gradient across the plasma membrane. We speculate that the mechanism might contribute to maintenance of acid-base balance in NPE.

Sign in / Sign up

Export Citation Format

Share Document