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Functional distinction of human EAG1 and EAG2 potassium channels
Author(s) -
Schönherr Roland,
Gessner Guido,
Löber Karsten,
Heinemann Stefan H.
Publication year - 2002
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(02)02365-7
Subject(s) - xenopus , potassium channel , gene isoform , quinidine , voltage gated potassium channel , chemistry , protein subunit , biophysics , potassium , patch clamp , ion channel , microbiology and biotechnology , biochemistry , biology , receptor , pharmacology , organic chemistry , gene
Human ether à go‐go potassium channel 2 (hEAG2) was cloned and its properties were compared with the previously characterized isoform hEAG1. In the Xenopus oocyte expression system the time course of activation was about four times slower and the voltage required for half‐maximal subunit activation was about 10 mV greater for hEAG2 channels. However, its voltage dependence was smaller and, therefore, hEAG2 channels start to open at more negative voltages than hEAG1. Coexpression of both isoforms and kinetic analysis of the resulting currents indicated that they can form heteromeric channel complexes in which the slow activation phenotype of hEAG2 is dominant. Upon expression in mammalian cells, quinidine blocked hEAG1 channels (IC 50 1.4 μM) more potently than hEAG2 channels (IC 50 152 μM), thus providing a useful tool for the functional distinction between hEAG1 and hEAG2 potassium channels.