Very High Single Channel Water Permeability of Aquaporin-4 in Baculovirus-Infected Insect Cells and Liposomes Reconstituted with Purified Aquaporin-4†

Biochemistry ◽  
1997 ◽  
Vol 36 (24) ◽  
pp. 7625-7632 ◽  
Author(s):  
Baoxue Yang ◽  
Alfred N. van Hoek ◽  
A. S. Verkman
Keyword(s):  
Water Permeability ◽  
Insect Cells ◽  
Single Channel ◽  
Aquaporin 4 ◽  
Channel Water ◽  
Infected Insect ◽  
Very High

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.

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

scholarly journals Micropipette Aspiration‐Based Assessment of Single Channel Water Permeability

2020 ◽  
Vol 15 (7) ◽  
pp. 1900450
Author(s):  
Danila Boytsov ◽  
Christof Hannesschlaeger ◽  
Andreas Horner ◽  
Christine Siligan ◽  
Peter Pohl
Keyword(s):  
Water Permeability ◽  
Single Channel ◽  
Micropipette Aspiration ◽  
Channel Water

scholarly journals Augmentation of Single Channel Water Permeability by Modification of Membrane Anchoring

2010 ◽  
Vol 98 (3) ◽  
pp. 279a-280a
Author(s):  
Florian Zocher ◽  
Tanya Polupanowa ◽  
Danila Boytsov ◽  
Guillem Portella ◽  
Bert de Groot ◽  
...  
Keyword(s):  
Water Permeability ◽  
Single Channel ◽  
Channel Water ◽  
Membrane Anchoring

scholarly journals Production, processing and partial purification of functional G protein βγ subunits in baculovirus-infected insect cells

1992 ◽  
Vol 286 (3) ◽  
pp. 677-680 ◽  
Author(s):  
J D Robishaw ◽  
V K Kalman ◽  
K L Proulx
Keyword(s):  
G Protein ◽  
G Proteins ◽  
Insect Cells ◽  
Expression System ◽  
Baculovirus Expression System ◽  
Partial Purification ◽  
Baculovirus Expression ◽  
Gamma Subunits ◽  
Infected Insect ◽  
Beta 2

As a result of the inability to resolve the heterogeneous mixture of G protein beta gamma subunits present in tissues, it has not been possible to compare different beta gamma subunits of the G proteins in terms of their proposed roles in receptor-effector coupling. This study was undertaken to establish the utility of the baculovirus expression system in producing homogeneous beta gamma subunits of defined composition for the comparative analysis of these subunits in reconstitution systems. In this study we report the expression, and appropriate post-translational processing, of recombinant beta 2, gamma 2 and gamma 3 subunits. In addition, we show that the recombinant beta gamma subunits can be readily purified, and can functionally interact with the alpha subunits of the G proteins.

Expression and Characterization of Human Dopamine D2Receptor in Baculovirus-Infected Insect Cells

1994 ◽  
Vol 14 (2) ◽  
pp. 99-117 ◽  
Author(s):  
J. A. Javitch ◽  
J. Kaback ◽  
X. Li ◽  
A. Karlin
Keyword(s):  
Insect Cells ◽  
Infected Insect

Expression of murine soluble CD4 protein in baculovirus infected insect cells

Immunobiology ◽  
1992 ◽  
Vol 186 (3-4) ◽  
pp. 254-267 ◽  
Author(s):  
Jörg Kupsch ◽  
Kai M. Saizawa ◽  
Klaus Eichmann
Keyword(s):  
Insect Cells ◽  
Infected Insect ◽  
Soluble Cd4
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