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It has been suggested that P-glycoprotein (P-gp), an ATP-dependent transporter responsible for classical multidrug resistance, is also a volume-regulated chloride channel. We reexamined this hypothesis by use of whole-cell patch clamp recordings of three matched pairs of cell lines, which were either drug-sensitive or drug-resistant due to P-gp overexpression. We demonstrate here that volume-regulated chloride-selective currents can be induced in cells with or without P-gp expression. Overexpression of either P-gp or cystic fibrosis transmembrane conductance regulator, the protein product of the CF gene and another member of the ATP-dependent transporters, is associated with a hypotonicity-induced, rapid onset, transient current prior to onset of the volume-sensitive chloride-selective current, an apparent nonspecific effect related to the overexpression of an integral membrane protein. These results suggest that there is no relationship between P-gp and the chloride channel activated by cell swelling.
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
May 1995,
The Biochemical journal,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
February 1995,
Journal of bioenergetics and biomembranes,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
March 1996,
The Journal of physiology,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
January 1995,
The Journal of physiology,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
January 1998,
Methods in enzymology,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
November 1995,
The Journal of biological chemistry,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
May 2000,
The Journal of physiology,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
October 1994,
The American journal of physiology,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
January 1994,
The Japanese journal of physiology,
Y Dong, and
K G Chen, and
G E Durán, and
K Kouyama, and
A C Chao, and
B I Sikic, and
S V Gollapudi, and
S Gupta, and
P Gardner
February 1996,
Pflugers Archiv : European journal of physiology,
