Functional incorporation of P-glycoprotein into Xenopus oocyte plasma membrane fails to elicit a swelling-evoked conductance.
Microinjecton of Xenopus oocytes with P-glycoprotein-containing membranes from multidrug resistant cells following a recently published procedure resulted in the transplantation of the protein to the plasma membrane of the oocytes and was confirmed by Western blot analysis. These oocytes showed a reduced intracellular accumulation of daunomycin, when compared to uninjected oocytes or to those injected with membrane vesicles lacking P-glycoprotein, thus indicating that the protein had been incorporated in a transport-competent form. On the other hand, transplantation of P-glycoprotein to the oocyte membrane did not significantly change either the appearance or the properties of swelling-elicited membrane conductance with respect to those determined in oocytes either uninjected or injected with membranes lacking P-glycoprotein. These results do not support a role for P-glycoprotein as a swelling-activated chloride channel.
Aleu
J
J
Instituto de Neurociencias, Universidad de Alicante, Alicante, 03080, Spain.
Ivorra
I
I
Lejarreta
M
M
Gonzalez-Ros
J M
JM
Morales
A
A
Ferragut
J A
JA
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D018432:Drug Resistance, Multiple; D007939:Leukemia L1210 / Q000378:metabolism / Q000473:pathology; D008564:Membrane Potentials; D051379:Mice; D009865:Oocytes / Q000378:metabolism* / Q000502:physiology; D014981:Xenopus
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1