The hypertonic environment differentially regulates wild-type CFTR and TNR-CFTR chloride channels

Roberta M. Lassance-Soares, Jie Cheng, Kristina Krasnov, Liudmila Cebotaru, Garry R. Cutting, Jackson Souza-Menezes, Marcelo M. Morales, William B. Guggino

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


This study tested the hypotheses that the hypertonic environment of the renal medulla regulates the expression of cystic fibrosis transmembrane conductance regulator protein (CFTR) and its natural splice variant, TNR-CFTR. To accomplish this, Madin-Darby canine kidney (MDCK) stable cell lines expressing TNR-CFTR or CFTR were used. The cells were treated with hypertonic medium made with either NaCl or urea or sucrose (480 mOsm/kg or 560 mOsm/kg) to mimic the tonicity of the renal medulla environment. Western blot data showed that CFTR and TNR-CFTR total cell protein is increased by hypertonic medium, but using the surface biotinylation technique, only CFTR was found to be increased in cell plasma membrane. Confocal microscopy showed TNR-CFTR localization primarily at the endoplasmic reticulum and plasma membrane. In conclusion, CFTR and TNR-CFTR have different patterns of distribution in MDCK cells and they are modulated by a hypertonic environment, suggesting their physiological importance in renal medulla.

Original languageEnglish (US)
Pages (from-to)577-586
Number of pages10
JournalCellular Physiology and Biochemistry
Issue number4-5
StatePublished - 2010


  • CFTR
  • Hypertonic environment
  • MDCK cells
  • Plasma membrane
  • Sodium chloride
  • Sucrose
  • Urea

ASJC Scopus subject areas

  • Physiology


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