Endogenous ClC-2 channels contribute to mammalian cell volume homeostasis

R. M. Roman, R. L. Smith, A. P. Feranchak, G. H. Clayton, J. G. Fitz

Research output: Contribution to journalArticle

Abstract

The molecular identity of the membrane Cl- channels responsible for cell volume homeostasis has not been defined. Since previous studies have shown that Xenopus-expressed ClC-2 channels activate during hypotonic exposure, our purpose was to evaluate whether endogenous mammalian ClC-2 channels contribute to volume-sensitive changes in membrane Cl- permeability. A cDNA closely homologous with rat brain ClC-2 was isolated from a model liver cell line that demonstrates swelling-activated currents typical of most mammalian cell types. Abundant cellular expression of ClC-2 mRNA and membrane localization of ClC-2 protein was shown by in situ hybridization and immunocytochemistry. Intracellular delivery of antibodies to the cytoplasmic amino-terminal region of ClC-2 thought to be important for channel gating nearly abolished Cl- current activation by volume increases or exposure to ATP. lntracellular injection of ClC-2 antibodies also prevented recovery of cell volume following swelling. The characteristics of volume-and ATP-stimulated unitary currents include a slope conductance that averaged 7.6 pS in symmetrical Cl- containing solutions, reversal near ECl, and a permeability ratio of NO3 - > Cl- > aspartate. These studies provide the first direct evidence that native mammalian ClC-2 channel proteins contribute to membrane Cl- permeability and volume homeostasis, and may have important implications for other cell types in light of the near ubiquitous expression of ClC-2.

Original languageEnglish (US)
JournalFASEB Journal
Volume12
Issue number5
StatePublished - Mar 20 1998

Fingerprint

Cell Size
Permeability
homeostasis
Homeostasis
Cells
Membranes
Adenosine Triphosphate
Swelling
Antibodies
membrane permeability
cells
Xenopus
Ion Channels
Aspartic Acid
In Situ Hybridization
Proteins
Complementary DNA
Immunohistochemistry
Liver
Rats

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

Cite this

Endogenous ClC-2 channels contribute to mammalian cell volume homeostasis. / Roman, R. M.; Smith, R. L.; Feranchak, A. P.; Clayton, G. H.; Fitz, J. G.

In: FASEB Journal, Vol. 12, No. 5, 20.03.1998.

Research output: Contribution to journalArticle

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