The human ether-a-go-go-related gene (hERG) encodes for the pore-forming subunit of the channel that conducts the rapidly activating delayed K + current (I Kr ) in the heart. The hERG channel is important for cardiac repolarization, and reduction of its expression in the plasma membrane due to mutations causes long-QT syndrome type 2 (LQT2). As such, promoting hERG membrane expression is a strategy to rescue mutant channel function. In the present study, we applied patch clamp, Western blots, immunocytochemistry, and Quantitative Reverse Transcription PCR (RT-qPCR) techniques to investigate the rescue effects of two drugs, remdesivir and lumacaftor, on trafficking defective mutant hERG channels. As our group has SIGNIFICANCE STATEMENTVarious naturally occurring mutations in a cardiac potassium channel called hERG can impair channel function by decreasing cell-surface channel expression, resulting in cardiac electrical disturbances and even sudden cardiac death. Promotion of cell-surface expression of mutant hERG channels represents a strategy to rescue channel function. This work demonstrates that drugs such as remdesivir and lumacaftor can differently affect homomeric and heteromeric mutant hERG channels, which have biological and clinical implications.

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