scholarly journals Aquaporin-4 Dynamics in Orthogonal Arrays in Live Cells Visualized by Quantum Dot Single Particle Tracking

2008 ◽  
Vol 19 (8) ◽  
pp. 3369-3378 ◽  
Author(s):  
Jonathan M. Crane ◽  
Alfred N. Van Hoek ◽  
William R. Skach ◽  
A. S. Verkman
Keyword(s):  
Plasma Membranes ◽  
Freeze Fracture ◽  
Orthogonal Arrays ◽  
Cell Types ◽  
Single Particle Tracking ◽  
Aquaporin 4 ◽  
Live Cells ◽  
Restoring Force ◽  
Orthogonal Arrays Of Particles ◽  
Freeze Fracture Electron Microscopy

Freeze-fracture electron microscopy (FFEM) indicates that aquaporin-4 (AQP4) water channels can assemble in cell plasma membranes in orthogonal arrays of particles (OAPs). We investigated the determinants and dynamics of AQP4 assembly in OAPs by tracking single AQP4 molecules labeled with quantum dots at an engineered external epitope. In several transfected cell types, including primary astrocyte cultures, the long N-terminal “M1” form of AQP4 diffused freely, with diffusion coefficient ∼5 × 10−10 cm2/s, covering ∼5 μm in 5 min. The short N-terminal “M23” form of AQP4, which by FFEM was found to form OAPs, was relatively immobile, moving only ∼0.4 μm in 5 min. Actin modulation by latrunculin or jasplakinolide did not affect AQP4-M23 diffusion, but deletion of its C-terminal postsynaptic density 95/disc-large/zona occludens (PDZ) binding domain increased its range by approximately twofold over minutes. Biophysical analysis of short-range AQP4-M23 diffusion within OAPs indicated a spring-like potential, with a restoring force of ∼6.5 pN/μm. These and additional experiments indicated that 1) AQP4-M1 and AQP4-M23 isoforms do not coassociate in OAPs; 2) OAPs can be imaged directly by total internal reflection fluorescence microscopy; and 3) OAPs are relatively fixed, noninterconvertible assemblies that do not require cytoskeletal or PDZ-mediated interactions for formation. Our measurements are the first to visualize OAPs in live cells.

Absence of orthogonal arrays in kidney, brain and muscle from transgenic knockout mice lacking water channel aquaporin-4

1997 ◽  
Vol 110 (22) ◽  
pp. 2855-2860 ◽  
Author(s):  
J.M. Verbavatz ◽  
T. Ma ◽  
R. Gobin ◽  
A.S. Verkman
Keyword(s):  
Cho Cells ◽  
Collecting Duct ◽  
Water Channel ◽  
Freeze Fracture ◽  
Orthogonal Arrays ◽  
Knock Out ◽  
Orthogonal Arrays Of Particles ◽  
Freeze Fracture Electron Microscopy ◽  
Knock Out Mice ◽  
And Function

Freeze-fracture electron microscopy (FFEM) of kidney collecting duct, muscle, astrocytes in brain, and other mammalian tissues has revealed regular square arrays of intramembrane particles called orthogonal arrays of particles (OAPs). Their possible role in membrane structure and transport have been proposed, and their absence or decrease has been noted in a variety of hereditary and acquired diseases. A transgenic mouse lacking water channel AQP4 was used to show that AQP4 is the OAP protein. FFEM was done on kidney, skeletal muscle, and brain from AQP4 wild-type [+/+], heterozygous [+/−] and knock-out [-/-] mice. The [-/-] mice did not express detectable AQP4 protein, but were grossly indistinguishable from [+/+] mice. FFEM was done on blinded samples of kidney, brain and muscle from 9 mice. In all 6 kidney samples from [+/+] and [+/−] mice, OAPs similar to those in AQP4-transfected CHO cells were found in basolateral membranes of collecting duct principal cells. In all muscle and brain samples from [+/+] and [+/−] mice, OAPs of identical ultrastructure to those in kidney were seen, but in smaller patch sizes. OAPs were not seen in any sample from [-/-] mice. Label-fracture analysis using a peptide-derived AQP4 polyclonal antibody showed immunogold labeling of OAPs in AQP4-expressing CHO cells. These studies provide direct evidence that AQP4 is required for formation of OAPs and is a component of OAPs, thus establishing the identity and function of OAPs.

scholarly journals Surface membrane vesicles from mononuclear cells stimulate erythroid stem cells to proliferate in culture

Blood ◽  
1982 ◽  
Vol 60 (3) ◽  
pp. 583-594 ◽  
Author(s):  
N Dainiak ◽  
CM Cohen
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Mononuclear Cells ◽  
Surface Membrane ◽  
Freeze Fracture ◽  
Membrane Vesicles ◽  
Cell Types ◽  
Target Cells ◽  
Freeze Fracture Electron Microscopy

Abstract In order to examine the contribution of cell surface materials to erythroid burst-promoting activity (BPA), we separated media conditioned by a variety of human cell types into pellets and supernatants by centrifugation. When added to serum-restricted cultures of nonadherent human marrow cells, pellets contained about half of the total stimulatory activity. Freeze-fracture electron microscopy of the pellets revealed the presence of unilamellar membrane vesicles ranging from 0.10 to 0.40 microM in diameter. The amount of BPA in culture increased with added vesicle concentration in a saturable fashion. Preparation of leukocyte conditioned medium (LCM) from 125I-wheat germ agglutinin labeled cells and studies comparing the glycoprotein composition of vesicles with that of leukocyte plasma membranes suggest that LCM-derived vesicles are of plasma membrane origin. Moreover, partially purified leukocyte plasma membrane preparations also contained BPA. While disruption of vesicles by freezing/thawing and hypotonic lysis did not alter BPA, heat, trypsin, or pronase treatment removed greater than 65% of BPA, implying that vesicle surface rather than intravesicular molecules express BPA. Results of BPA assays performed in two-layer clots indicated that proximity to target cells is required for vesicle BPA expression. We conclude that membrane vesicles spontaneously shed from cell surfaces may be important regulators of erythroid burst proliferation in vitro.

scholarly journals Surface membrane vesicles from mononuclear cells stimulate erythroid stem cells to proliferate in culture

Blood ◽  
1982 ◽  
Vol 60 (3) ◽  
pp. 583-594
Author(s):  
N Dainiak ◽  
CM Cohen
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Mononuclear Cells ◽  
Surface Membrane ◽  
Freeze Fracture ◽  
Membrane Vesicles ◽  
Cell Types ◽  
Target Cells ◽  
Freeze Fracture Electron Microscopy

In order to examine the contribution of cell surface materials to erythroid burst-promoting activity (BPA), we separated media conditioned by a variety of human cell types into pellets and supernatants by centrifugation. When added to serum-restricted cultures of nonadherent human marrow cells, pellets contained about half of the total stimulatory activity. Freeze-fracture electron microscopy of the pellets revealed the presence of unilamellar membrane vesicles ranging from 0.10 to 0.40 microM in diameter. The amount of BPA in culture increased with added vesicle concentration in a saturable fashion. Preparation of leukocyte conditioned medium (LCM) from 125I-wheat germ agglutinin labeled cells and studies comparing the glycoprotein composition of vesicles with that of leukocyte plasma membranes suggest that LCM-derived vesicles are of plasma membrane origin. Moreover, partially purified leukocyte plasma membrane preparations also contained BPA. While disruption of vesicles by freezing/thawing and hypotonic lysis did not alter BPA, heat, trypsin, or pronase treatment removed greater than 65% of BPA, implying that vesicle surface rather than intravesicular molecules express BPA. Results of BPA assays performed in two-layer clots indicated that proximity to target cells is required for vesicle BPA expression. We conclude that membrane vesicles spontaneously shed from cell surfaces may be important regulators of erythroid burst proliferation in vitro.

scholarly journals Histamine treatment induces rearrangements of orthogonal arrays of particles (OAPs) in human AQP4-expressing gastric cells

2001 ◽  
Vol 154 (6) ◽  
pp. 1235-1244 ◽  
Author(s):  
Monica Carmosino ◽  
Giuseppe Procino ◽  
Grazia Paola Nicchia ◽  
Roberta Mannucci ◽  
Jean-Marc Verbavatz ◽  
...  
Keyword(s):  
Cell Line ◽  
Basolateral Membrane ◽  
Water Channel ◽  
Freeze Fracture ◽  
Orthogonal Arrays ◽  
Short Term ◽  
Water Permeability Coefficient ◽  
Cell Surface Biotinylation ◽  
Osmotic Water ◽  
Orthogonal Arrays Of Particles

To test the involvement of the water channel aquaporin (AQP)-4 in gastric acid physiology, the human gastric cell line (HGT)-1 was stably transfected with rat AQP4. AQP4 was immunolocalized to the basolateral membrane of transfected HGT-1 cells, like in native parietal cells. Expression of AQP4 in transfected cells increased the osmotic water permeability coefficient (Pf) from 2.02 ± 0.3 × 10−4 to 16.37 ± 0.5 × 10−4 cm/s at 20°C. Freeze-fracture EM showed distinct orthogonal arrays of particles (OAPs), the morphological signature of AQP4, on the plasma membrane of AQP4-expressing cells. Quantitative morphometry showed that the density of OAPs was 2.5 ± 0.3% under basal condition and decreased by 50% to 1.2 ± 0.3% after 20 min of histamine stimulation, mainly due to a significant decrease of the OAPs number. Concomitantly, Pf decreased by ∼35% in 20-min histamine-stimulated cells. Both Pf and OAPs density were not modified after 10 min of histamine exposure, time at which the maximal hormonal response is observed. Cell surface biotinylation experiments confirmed that AQP4 is internalized after 20 min of histamine exposure, which may account for the downregulation of water transport. This is the first evidence for short term rearrangement of OAPs in an established AQP4-expressing cell line.

scholarly journals Erythrocyte membrane plaques from rats with magnesium deficiency

Blood ◽  
1977 ◽  
Vol 49 (4) ◽  
pp. 657-664 ◽  
Author(s):  
RJ Elin ◽  
HK Tan
Keyword(s):  
Erythrocyte Membrane ◽  
Plasma Membranes ◽  
Magnesium Deficiency ◽  
Freeze Fracture ◽  
Deficient Diet ◽  
White Rats ◽  
Dietary Magnesium ◽  
Freeze Fracture Electron Microscopy ◽  
And Control ◽  
Fracture Electron

Abstract This study investigated the anemia of dietary magnesium deficiency in inbred Fisher white rats using freeze-fracture electron microscopy. The plasma membranes of erythrocytes from animals receiving two different magnesium-deficient and control diets were observed at weekly or biweekly intervals for 6 wk. The earliest changes were small plaques on the external surface (ES) and fracture face (PF) of erythrocyte plasma membranes, which occurred after 2 wk of either magnesium-deficient diet. These plaques persisted and increased in size with progressive magnesium deficiency. When fully developed, the plaques consisted of round or oval elevations approximately 30–50 nm in diameter outlined by a narrow raised border. The surface of the plaques was smooth and devoid of intramembranous particles. Incubation of erythrocytes from magnesium-deficient rats in a physiologic solution containing 2 meq/liter magnesium for 1 hr at 37degrees C did not alter the appearance of the plaques. Erythrocytes from control rats, obtained during the same time periods, showed no plaques. Thus, a deficiency of magnesium in rats altered erythrocyte membrane structure.

Structure and Functions of Aquaporin-4-Based Orthogonal Arrays of Particles

2011 ◽  
pp. 1-41 ◽  
Author(s):  
Hartwig Wolburg ◽  
Karen Wolburg-Buchholz ◽  
Petra Fallier-Becker ◽  
Susan Noell ◽  
Andreas F. Mack
Keyword(s):  
Orthogonal Arrays ◽  
Aquaporin 4 ◽  
Orthogonal Arrays Of Particles ◽  
Structure And Functions

scholarly journals Aquaporin-4 orthogonal arrays of particles from a physiological and pathophysiological point of view

2013 ◽  
Vol 2 (4) ◽  
pp. 143-154 ◽  
Author(s):  
Grazia Paola Nicchia ◽  
Francesco Pisani ◽  
Angelo Sparaneo ◽  
Maria Grazia Mola ◽  
Davide Basco ◽  
...  
Keyword(s):  
Orthogonal Arrays ◽  
Point Of View ◽  
Aquaporin 4 ◽  
Orthogonal Arrays Of Particles

scholarly journals Is Upregulation of Aquaporin 4-M1 Isoform Responsible for the Loss of Typical Orthogonal Arrays of Particles in Astrocytomas?

2016 ◽  
Vol 17 (8) ◽  
pp. 1230 ◽  
Author(s):  
Petra Fallier-Becker ◽  
Maike Nieser ◽  
Ulrike Wenzel ◽  
Rainer Ritz ◽  
Susan Noell
Keyword(s):  
Orthogonal Arrays ◽  
Aquaporin 4 ◽  
Orthogonal Arrays Of Particles
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