Control of the Aquaporin-4 Channel Water Permeability by Structural Dynamics of Aromatic/Arginine Selectivity Filter Residues

Biochemistry ◽  
2015 ◽  
Vol 54 (45) ◽  
pp. 6753-6755 ◽  
Author(s):  
Philip Kitchen ◽  
Alex C. Conner
Keyword(s):  
Structural Dynamics ◽  
Water Permeability ◽  
Selectivity Filter ◽  
Aquaporin 4 ◽  
Channel Water

scholarly journals Novel variants in human Aquaporin-4 reduce cellular water permeability

2008 ◽  
Vol 17 (15) ◽  
pp. 2379-2389 ◽  
Author(s):  
M. D. Sorani ◽  
Z. Zador ◽  
E. Hurowitz ◽  
D. Yan ◽  
K. M. Giacomini ◽  
...  
Keyword(s):  
Water Permeability ◽  
Aquaporin 4 ◽  
Novel Variants ◽  
Cellular Water

Regulation of water permeability through aquaporin-4

Neuroscience ◽  
2010 ◽  
Vol 168 (4) ◽  
pp. 885-891 ◽  
Author(s):  
Y. Yukutake ◽  
M. Yasui
Keyword(s):  
Water Permeability ◽  
Aquaporin 4

Membrane organization and function of M1 and M23 isoforms of aquaporin-4 in epithelial cells

2004 ◽  
Vol 287 (3) ◽  
pp. F501-F511 ◽  
Author(s):  
Claudia Silberstein ◽  
Richard Bouley ◽  
Yan Huang ◽  
Pingke Fang ◽  
Nuria Pastor-Soler ◽  
...  
Keyword(s):  
Water Permeability ◽  
Single Channel ◽  
Phosphorylation Site ◽  
Freeze Fracture ◽  
Parietal Cells ◽  
Aquaporin 4 ◽  
Osmotic Water Permeability ◽  
Cellular Expression ◽  
Water Permeability Coefficient ◽  
Osmotic Water

Aquaporin-4 (AQP4) water channels exist as heterotetramers of M1 and M23 splice variants and appear to be present in orthogonal arrays of intramembraneous particles (OAPs) visualized by freeze-fracture microscopy. We report that AQP4 forms OAPs in rat gastric parietal cells but not in parietal cells from the mouse or kangaroo rat. Furthermore, the organization of principal cell OAPs in Brattleboro rat kidney is perturbed by vasopressin (arginine vasopressin). Membranes of LLC-PK1 cells expressing M23-AQP4 showed large, abundant OAPs, but none were detectable in cells expressing M1-AQP4. Measurements of osmotic swelling of transfected LLC-PK1 cells using videomicroscopy, gave osmotic water permeability coefficient ( Pf) values (in cm/s) of 0.018 (M1-AQP4), 0.019 (M23-AQP4), and 0.003 (control). Quantitative immunoblot and immunofluorescence showed an eightfold greater expression of M1- over M23-AQP4 in the cell lines, suggesting that single-channel pf (cm3/s) is much greater for the M23 variant. Somatic fusion of M1- and M23-AQP4 cells ( Pf = 0.028 cm/s) yielded OAPs that were fewer and smaller than in M23 cells alone, and M1-to-M23 expression ratios (∼1:4) normalized to AQP4 in M1 or M23 cells indicated a reduced single-channel pf for the M23 variant. Expression of an M23-AQP4-Ser111E mutant produced ∼1.5-fold greater single-channel pf and OAPs that were up to 2.5-fold larger than wild-type M23-AQP4 OAPs, suggesting that a putative PKA phosphorylation site Ser111 is involved in OAP formation. We conclude that the higher-order organization of AQP4 in OAPs increases single-channel osmotic water permeability by one order of magnitude and that differential cellular expression levels of the two isoforms could regulate this organization.

Lead induces increased water permeability in astrocytes expressing aquaporin 4

Neuroscience ◽  
2005 ◽  
Vol 136 (1) ◽  
pp. 105-114 ◽  
Author(s):  
E. Gunnarson ◽  
G. Axehult ◽  
G. Baturina ◽  
S. Zelenin ◽  
M. Zelenina ◽  
...  
Keyword(s):  
Water Permeability ◽  
Aquaporin 4

scholarly journals Quantitative Measurement of Diffusion-weighted Imaging Signal Using Expression-controlled Aquaporin-4 Cells: Comparative Study of 2-compartment and Diffusion Kurtosis Imaging Models

2021 ◽  
Author(s):  
Akiko Imaizumi ◽  
Takayuki Obata ◽  
Jeff Kershaw ◽  
Yasuhiko Tachibana ◽  
Yoichiro Abe ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Water Permeability ◽  
Diffusion Weighted Imaging ◽  
Aquaporin 4 ◽  
Diffusion Kurtosis Imaging ◽  
Parameter Estimates ◽  
Aqp4 Expression ◽  
Diffusion Weighted ◽  
Diffusion Kurtosis ◽  
And Diffusion

Purpose: The purpose of this study was to compare parameter estimates for the 2-compartment (2Comp) and diffusion kurtosis imaging (DKm) models obtained from diffusion-weighted imaging (DWI) of aquaporin-4 (AQP4) expression-controlled cells, and to look for biomarkers that indicate differences in the cell membrane water permeability. Methods: DWI was performed on AQP4-expressing and non-expressing cells and the signal was analyzed with the 2Comp and DKm models. For the 2Comp model, the diffusion coefficients (Df, Ds) and volume fractions (Ff, Fs, Ff=1-Fs) of the fast and slow compartments were estimated. For the DKm model, estimates of the diffusion kurtosis (K) and corrected diffusion coefficient (D) were obtained. Results: For the 2Comp model, Ds and Fs showed clear differences between AQP4-expressing and non-expressing cells. Fs was also sensitive to cell density. There was no clear relationship with the cell type for the DKm parameters. Conclusions: Changes to cell membrane water permeability due to AQP4 expression affected DWI of cell suspensions. For the 2Comp and DKm models, Ds was the parameter most sensitive to differences in AQP4 expression.

scholarly journals Mercury chloride decreases the water permeability of aquaporin-4-reconstituted proteoliposomes

2008 ◽  
Vol 100 (9) ◽  
pp. 561-561
Author(s):  
Yoshinori Yukutake ◽  
Shoji Tsuji ◽  
Yoshinori Hirano ◽  
Takeshi Adachi ◽  
Toshiyuki Takahashi ◽  
...  
Keyword(s):  
Water Permeability ◽  
Aquaporin 4 ◽  
Mercury Chloride

scholarly journals Monitoring Single-channel Water Permeability in Polarized Cells

2011 ◽  
Vol 286 (46) ◽  
pp. 39926-39932 ◽  
Author(s):  
Liudmila Erokhova ◽  
Andreas Horner ◽  
Philipp Kügler ◽  
Peter Pohl
Keyword(s):  
Water Permeability ◽  
Single Channel ◽  
Channel Water ◽  
Polarized Cells

Differential water permeability and regulation of three aquaporin 4 isoforms

2009 ◽  
Vol 67 (5) ◽  
pp. 829-840 ◽  
Author(s):  
Robert A. Fenton ◽  
Hanne B. Moeller ◽  
Marina Zelenina ◽  
Marteinn T. Snaebjornsson ◽  
Torgeir Holen ◽  
...  
Keyword(s):  
Water Permeability ◽  
Aquaporin 4
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