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Chronic exposure to EGF affects trafficking and function of ENaC channel in cystic fibrosis cells
- Source :
-
Biochemical & Biophysical Research Communications . Jun2005, Vol. 331 Issue 2, p503-511. 9p. - Publication Year :
- 2005
-
Abstract
- Abstract: Using the whole-cell patch-clamp technique, we identified an amiloride (AMI)-sensitive Na+ current in cystic fibrosis cells, JME/CF15, growing in standard medium. The reversal potential of this current depended on Na+ concentrations and the cation selectivity was much higher for Na+ than for K+, indicating that the current is through ENaC channels. In contrast, cells from EGF-containing medium lacked AMI-sensitive Na+ currents. In permeabilized cells growing in EGF-containing medium, αENaC was mainly detected in a perinuclear region, while in cells from standard medium it was distributed over the cell body. Western-blot analysis showed that in standard medium cells expressed fast-migrating EndoH-insensitive and slow-migrating EndoH-sensitive αENaC fractions, while in cells growing in the presence of EGF, αENaC was only detected as the fast-migrating EndoH-insensitive fraction. Long-term incubation of cells with EGF resulted in an increased basal Ca2+ level, [Ca2+]i. A similar increase of [Ca2+]i was also observed in the presence of 2μM thapsigargin, resulting in inhibition of ENaC function. Thus, in JME/CF15 cells inhibition of the ENaC function by chronic incubation with EGF is a Ca2+-mediated process that affects trafficking and surface expression of ENaC channels. [Copyright &y& Elsevier]
- Subjects :
- *AMILORIDE
*CYSTIC fibrosis
*CELLS
*GENETIC disorders
Subjects
Details
- Language :
- English
- ISSN :
- 0006291X
- Volume :
- 331
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Biochemical & Biophysical Research Communications
- Publication Type :
- Academic Journal
- Accession number :
- 17021121
- Full Text :
- https://doi.org/10.1016/j.bbrc.2005.03.201