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Cyclosporin A selectively reduces the functional expression of Kir2.1 potassium channels in Xenopus oocytes
Author(s) -
Chen Haijun,
Kubo Yoshihiro,
Hoshi Toshinori,
Heinemann Stefan H
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00028-3
Subject(s) - xenopus , potassium channel , potassium channel blocker , chemistry , ion channel , pharmacology , microbiology and biotechnology , biology , biophysics , biochemistry , receptor , gene
The immunosuppressant cyclosporin A (CsA) reduced the functional expression of Kir2.1 potassium channels in Xenopus oocytes in a dose‐dependent manner with an IC 50 of 11 μM when the oocytes were incubated with CsA after RNA injection. FK506 was less effective than CsA; cyclosporin H, a non‐immunosuppressive derivative of CsA, did not have a significant effect. CsA did not impair protein synthesis since other potassium channel types (Kir1.1, Kv1.1, Kv1.4) were much less sensitive to CsA. Our results suggest that the functional expression of Kir2.1 channels is facilitated by the peptidyl‐prolyl isomerase cyclophilin. The observations illustrate a new role of CsA in regulation of membrane ion transport, and may provide an alternative explanation for CsA‐induced side effects in clinical use.