A mechanistic link between an inherited and an acquired cardiac arrhythmia: HERG encodes the IKr potassium channel.
Mutations in HERG cause an inherited cardiac arrhythmia, long QT syndrome (LQT). To define the function of HERG, we expressed the protein in Xenopus oocytes. The biophysical properties of expressed HERG are nearly identical to the rapidly activating delayed rectifier K+ current (IKr) in cardiac myocytes. HERG current is K+ selective, declines with depolarizations above 0 mV, is activated by extracellular K+, and is blocked by lanthanum. Interestingly, HERG current is not blocked by drugs that specifically block IKr in cardiac myocytes. These data indicate that HERG proteins form IKr channels, but that an additional subunit may be required for drug sensitivity. Since block of IKr is a known mechanism for drug-induced cardiac arrhythmias, the finding that HERG encodes IKr channels provides a mechanistic link between certain forms of inherited and acquired LQT.
Sanguinetti
M C
MC
Eccles Program in Human Molecular Biology and Genetics, University of Utah Health Sciences Center, Salt Lake City 84112, USA.
Jiang
C
C
Curran
M E
ME
Keating
M T
MT
D000818:Animals; D027682:Cation Transport Proteins; D003001:Cloning, Molecular; D003035:Cobalt / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins; D000072237:ERG1 Potassium Channel; D004553:Electric Conductivity; D051638:Ether-A-Go-Go Potassium Channels; D006801:Humans; D015640:Ion Channel Gating; D007811:Lanthanum / Q000494:pharmacology; D008133:Long QT Syndrome / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials; D008845:Microinjections; D009712:Nucleotides, Cyclic / Q000494:pharmacology; D009865:Oocytes; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D011994:Recombinant Proteins / Q000378:metabolism; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D014981:Xenopus
D027682:Cation Transport Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C072312:ERG protein, human; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; C092509:KCNH6 protein, human; D009712:Nucleotides, Cyclic; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D011994:Recombinant Proteins; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D003035:Cobalt; D007811:Lanthanum; D011188:Potassium