scholarly journals Host-Cell Type Dependent Features of Recombinant Human Aquaporin-4 Orthogonal Arrays of Particles—New Insights for Structural and Functional Studies

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 119
Author(s):  
Francesco Pisani ◽  
Laura Simone ◽  
Maria Mola ◽  
Manuela De Bellis ◽  
Maria Mastrapasqua ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Mammalian Cell ◽  
Expression System ◽  
Orthogonal Arrays ◽  
Aquaporin 4 ◽  
Size Exclusion ◽  
Cell Type ◽  
Functional Studies ◽  
Mammalian Cell Lines ◽  
Orthogonal Arrays Of Particles

The CNS plasma-membrane water channel aquaporin-4 (AQP4) is expressed as two major isoforms able to aggregate into supramolecular assemblies known as ‘orthogonal arrays of particles’ (OAPs). OAP subnanometric features are largely unknown mainly because a method for the expression, isolation, and crystallization of integral human OAPs has not been developed. Here, the human OAP-forming isoform M23-AQP4 was expressed in insect and mammalian cell lines and AQP4 and OAP features evaluated. Native size exclusion chromatography was employed to isolate and analyze authentically folded OAPs, and neuromyelitis optica (NMO)-specific sandwich ELISA was developed to test OAP-integrity. The results demonstrate that in insect cells most AQP4 remains intracellular and unfolded and that OAPs are largely disassembled after the detergent extraction step. In mammalian cells, AQP4 showed regular plasma membrane targeting and OAPs exhibited strong post-extraction stability. Starting from the mammalian cell expression system, we isolated authentically folded OAPs. Together these data suggest a new strategy for expressing and isolating integral recombinant human OAPs and providing new insights into the cell-type dependent OAP-assembly and post-extraction stability, potentially useful to design new approaches for structural and functional studies of OAP and for other plasma membrane proteins organized into supramolecular structures.

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

scholarly journals Super-resolution imaging of aquaporin-4 orthogonal arrays of particles in cell membranes

2012 ◽  
Vol 125 (18) ◽  
pp. 4405-4412 ◽  
Author(s):  
A. Rossi ◽  
T. J. Moritz ◽  
J. Ratelade ◽  
A. S. Verkman
Keyword(s):  
Cell Membranes ◽  
Super Resolution ◽  
Orthogonal Arrays ◽  
Aquaporin 4 ◽  
Orthogonal Arrays Of Particles ◽  
Resolution Imaging

scholarly journals Indirect Role of AQP4b and AQP4d Isoforms in Dynamics of Astrocyte Volume and Orthogonal Arrays of Particles

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 735 ◽  
Author(s):  
Marjeta Lisjak ◽  
Maja Potokar ◽  
Robert Zorec ◽  
Jernej Jorgačevski
Keyword(s):  
Plasma Membrane ◽  
Cell Volume ◽  
Volume Regulation ◽  
Water Channel ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Orthogonal Arrays ◽  
Cell Swelling ◽  
Early Endosomes ◽  
Orthogonal Arrays Of Particles

Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the central nervous system (CNS). It is predominantly expressed in astrocytes lining blood–brain and blood–liquor boundaries. AQP4a (M1), AQP4c (M23), and AQP4e, present in the plasma membrane, participate in the cell volume regulation of astrocytes. The function of their splicing variants, AQP4b and AQP4d, predicted to be present in the cytoplasm, is unknown. We examined the cellular distribution of AQP4b and AQP4d in primary rat astrocytes and their role in cell volume regulation. The AQP4b and AQP4d isoforms exhibited extensive cytoplasmic localization in early and late endosomes/lysosomes and in the Golgi apparatus. Neither isoform localized to orthogonal arrays of particles (OAPs) in the plasma membrane. The overexpression of AQP4b and AQP4d isoforms in isoosmotic conditions reduced the density of OAPs; in hypoosmotic conditions, they remained absent from OAPs. In hypoosmotic conditions, the AQP4d isoform was significantly redistributed to early endosomes, which correlated with the increased trafficking of AQP4-laden vesicles. The overexpression of AQP4d facilitated the kinetics of cell swelling, without affecting the regulatory volume decrease. Therefore, although they reside in the cytoplasm, AQP4b and AQP4d isoforms may play an indirect role in astrocyte volume changes.

All functional aquaporin-4 isoforms are expressed in the rat cochlea and contribute to the formation of orthogonal arrays of particles

Neuroscience ◽  
2011 ◽  
Vol 189 ◽  
pp. 79-92 ◽  
Author(s):  
B. Hirt ◽  
C. Gleiser ◽  
A. Eckhard ◽  
A.F. Mack ◽  
M. Müller ◽  
...  
Keyword(s):  
Orthogonal Arrays ◽  
Aquaporin 4 ◽  
Rat Cochlea ◽  
Orthogonal Arrays Of Particles

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.

Sign in / Sign up

Export Citation Format

Share Document