Abstract
The relationships between P-glycoprotein (PGP) expression and plasma membrane ion currents activated by cell swelling were studied in several cell lines by use of the whole cell configuration of the patch-clamp technique. Swelling-activated Cl currents (I(Cl)/(s)) had similar characteristics independently of whether PGP was expressed. Addition of the anti-PGP monoclonal antibody C219 or its Fab fragment to the pipette solution prevented I(Cl)/(s) in cells expressing functional PGP (assessed by immunoblots, immunofluorescence, and transport of rhodamine 123) but not in cells lacking PGP expression. A peptide analogue of the C219 epitope abolished the effect of C219. Other anti-PGP antibodies and mouse immunoglobulin G were ineffective. C219 did not alter swelling-activated cation currents. Inasmuch as I(Cl)/(s) is present in cells that do not express PGP and C219 has no effect on I(Cl)/(s) in these cells, we conclude that PGP is not required for the I(Cl)/(s) phenotype. However, when expressed in the plasma membrane, PGP is involved, directly or indirectly, in I(Cl)/(s) but not in swelling-activated K+ currents.
Original language | English (US) |
---|---|
Pages (from-to) | C1370-C1378 |
Journal | American Journal of Physiology - Cell Physiology |
Volume | 270 |
Issue number | 5 39-5 |
DOIs | |
State | Published - May 1996 |
Keywords
- C219
- MCF-7
- cell volume regulation
- chloride channels
- multidrug resistance
- rhodamine 123
ASJC Scopus subject areas
- Physiology
- Cell Biology