DOI: 10.1073/pnas.95.20.11981. Direct immunogold labeling of aquaporin-4 in square arrays of astrocyte and ependymocyte plasma membranes in rat brain and spinal cord

Direct immunogold labeling of aquaporin-4 in square arrays of astrocyte and ependymocyte plasma membranes in rat brain and spinal cord

10.1073/pnas.95.20.11981

Crossref journal-article

Proceedings of the National Academy of Sciences

Proceedings of the National Academy of Sciences (341)

Abstract

Aquaporin (AQP) water channels are abundant in the brain and spinal cord, where AQP1 and AQP4 are believed to play major roles in water metabolism and osmoregulation. Immunocytochemical analysis of the brain recently revealed that AQP4 has a highly polarized distribution, with marked expression in astrocyte end-feet that surround capillaries and form the glia limitans; however, the structural organization of AQP4 has remained unknown. In freeze-fracture replicas, astrocyte end-feet contain abundant square arrays of intramembrane particles that parallel the distribution of AQP4. To determine whether astrocyte and ependymocyte square arrays contain AQP4, we employed immunogold labeling of SDS-washed freeze-fracture replicas and stereoscopic confirmation of tissue binding. Antibodies to AQP4 directly labeled ≈33% of square arrays in astrocyte and ependymocyte plasma membranes in rat brain and spinal cord. Overall, 84% of labels were present beneath square arrays; 11% were beneath particle clusters that resembled square arrays that had been altered during fixation or cleaving; and 5% were beneath the much larger areas of glial plasma membrane that were devoid of square arrays. Based on this evidence that AQP4 is concentrated in glial square arrays, freeze-fracture methods may now provide biophysical insights regarding neuropathological states in which abnormal fluid shifts are accompanied by alterations in the aggregation state or the molecular architecture of square arrays.

Bibliography

Rash, J. E., Yasumura, T., Hudson, C. S., Agre, P., & Nielsen, S. (1998). Direct immunogold labeling of aquaporin-4 in square arrays of astrocyte and ependymocyte plasma membranes in rat brain and spinal cord. Proceedings of the National Academy of Sciences, 95(20), 11981â11986.

Authors 5

John E. Rash (first)
Thomas Yasumura (additional)
C. Sue Hudson (additional)
Peter Agre (additional)
Søren Nielsen (additional)

References 45 Referenced 508

A K Johnson, A D Loewy Central Regulation of Autonomic Functions, eds A D Loewy, K M Spyer (Oxford Univ. Press, London) 14, 247–267 (1990). (10.1093/oso/9780195051063.003.0014) / Central Regulation of Autonomic Functions by Johnson A K (1990)
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J E Rash, R K Dillman, M Morita, L R Whalen, P B Guthrie, D Fay-Guthrie, D W Wheeler Rapid Freezing, Freeze Fracture, and Deep Etching, eds N J Severs, D M Shotton (Wiley-Liss, New York) 1, 127–150 (1995). / Rapid Freezing, Freeze Fracture, and Deep Etching by Rash J E (1995)
J E Rash, T J A Johnson, J E Dinchuk, D S Duch, S R Levinson Freeze-Fracture Studies of Membranes, ed S W Hui (CRC Press, Boca Raton, FL) 3, 41–59 (1990). / Freeze-Fracture Studies of Membranes by Rash J E (1990)
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10.1126/science.3726539

Dates

Type	When
Created	23 years, 1 month ago (July 26, 2002, 10:40 a.m.)
Deposited	1 year, 8 months ago (Jan. 3, 2024, 11:59 p.m.)
Indexed	1 month, 2 weeks ago (July 20, 2025, 12:18 a.m.)
Issued	26 years, 11 months ago (Sept. 29, 1998)
Published	26 years, 11 months ago (Sept. 29, 1998)
Published Online	26 years, 11 months ago (Sept. 29, 1998)
Published Print	26 years, 11 months ago (Sept. 29, 1998)

Funders 0

None

BibTeX

@article{Rash_1998, title={Direct immunogold labeling of aquaporin-4 in square arrays of astrocyte and ependymocyte plasma membranes in rat brain and spinal cord}, volume={95}, ISSN={1091-6490}, url={http://dx.doi.org/10.1073/pnas.95.20.11981}, DOI={10.1073/pnas.95.20.11981}, number={20}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Rash, John E. and Yasumura, Thomas and Hudson, C. Sue and Agre, Peter and Nielsen, Søren}, year={1998}, month=sep, pages={11981–11986} }

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