Amiloride-sensitive sodium channel is linked to the cytoskeleton in renal epithelial cells

Journal Article · Thu Aug 15 00:00:00 EDT 1991 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.88.16.6971· OSTI ID:5822663

Smith, P R; Saccomani, G; Benos, D J ^[1]; Eun-Hye, J; Angelides, K J ^[2]

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1. Univ. of Alabama, Birmingham (United States)
2. Baylor College of Medicine, Houston, TX (United States)

Amiloride-sensitive sodium channels are localized to the microvillar domain of apical membranes in sodium-transporting renal epithelial cells. To elucidate the elements that maintain sodium channel distribution at the apical membrane, the authors searched for specific proteins associating with the channel. Triton X-100 extraction of A6 epithelial cells reveals that sodium channels are associated with detergent-insoluble and assembled cytoskeleton. Indirect immunofluorescence and confocal microscopy show that sodium channels are segregated to the apical microvillar membrane and colocalize with ankyrin, fodrin, and actin. They document by immunoblot analysis that ankyrin and fodrin remain associated with sodium channels after isolation and purification form bovine renal papillae. {sup 125}I-labeled ankyrin can be precipitated by anti-sodium-channel antibodies only in the presence of purified bovine sodium-channel complex. Direct binding of {sup 125}I-labeled ankyrin shows ankyrin binds to the 150-kDa sub-unit of the channel. Fluorescence photobleach lateral-diffusion measurements indicate sodium channels are severely restricted in their lateral mobility. They conclude that ankyrin links the amiloride-sensitive sodium channel to the underlying cytoskeleton and this association may sequester sodium channels at apical microvilli and maintain their polarized distribution in renal epithelial cells.

• OSTI ID: 5822663
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 88:16; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
DIURETICS
BIOLOGICAL EFFECTS
PROTEINS
RADIORECEPTOR ASSAY
SODIUM COMPOUNDS
MEMBRANE TRANSPORT
ACTIN
EPITHELIUM
IODINE 125
KIDNEYS
ALKALI METAL COMPOUNDS
ANIMAL TISSUES
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
TISSUES
TRACER TECHNIQUES
550200* - Biochemistry