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XB-ART-50592
Mol Pharmacol 2015 Jul 01;881:19-28. doi: 10.1124/mol.115.098384.
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C-Linker Accounts for Differential Sensitivity of ERG1 and ERG2 K+ Channels to RPR260243-Induced Slow Deactivation.

Gardner A , Sanguinetti MC .


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Compounds can activate human ether-à-go-go-related gene 1 (hERG1) channels by several different mechanisms, including a slowing of deactivation, an increase in single channel open probability, or a reduction in C-type inactivation. The first hERG1 activator to be discovered, RPR260243 ((3R,4R)-4-[3-(6-methoxyquinolin-4-yl)-3-oxo-propyl]-1-[3-(2,3,5-trifluorophenyl)-prop-2-ynyl]-piperidine-3-carboxylic acid) (RPR) induces a pronounced, voltage-dependent slowing of hERG1 deactivation. The putative binding site for RPR, previously mapped to a hydrophobic pocket located between two adjacent subunits, is fully conserved in the closely related rat ether-à-go-go-related gene 2 (rERG2), yet these channels are relatively insensitive to RPR. Here, we use site-directed mutagenesis and heterologous expression of channels in Xenopus oocytes to characterize the structural basis for the differential sensitivity of hERG1 and rERG2 channels to RPR. Analysis of hERG1-rERG2 chimeric channels indicated that the structural determinant of channel sensitivity to RPR was located within the cytoplasmic C-terminus. Analysis of a panel of mutant hERG1 and rERG2 channels further revealed that seven residues, five in the C-linker and two in the adjacent region of the cyclic nucleotide-binding homology domain, can fully account for the differential sensitivity of hERG1 and rERG2 channels to RPR. These findings provide further evidence that the C-linker is a key structural component of slow deactivation in ether-à-go-go-related gene channels.

???displayArticle.pubmedLink??? 25888115
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Species referenced: Xenopus laevis
Genes referenced: gnao1 kcnh2 kcnh6

References [+] :
Abbruzzese, Modification of hERG1 channel gating by Cd2+. 2010, Pubmed, Xenbase