Human EAG channels are directly modulated by PIP2 as revealed by electrophysiological and optical interference investigations

• Published in: Scientific reports Vol. 6; no. 1; p. 23417
• Main Authors: Han, Bo, He, Kunyan, Cai, Chunlin, Tang, Yin, Yang, Linli, Heinemann, Stefan H., Hoshi, Toshinori, Hou, Shangwei
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.03.2016; Nature Publishing Group
• Subjects: 14/19; 38/109; 42/70; 631/443; 631/57; 631/80/86/2372; 82/80; Binding Sites; Calcium-binding protein; Calmodulin; Calmodulin - metabolism; Cancer; Central nervous system; Channel gating; Electrophysiological Phenomena; Ether-A-Go-Go Potassium Channels - chemistry; Ether-A-Go-Go Potassium Channels - metabolism; Fatty acids; Gene Expression Regulation; HEK293 Cells; Humanities and Social Sciences; Humans; Interferometry; Kinases; Laboratories; Lipids; Membrane Potentials - drug effects; Microscopy, Confocal; multidisciplinary; Nervous system; Phosphatidylinositol 4,5-diphosphate; Phosphatidylinositol 4,5-Diphosphate - metabolism; Phospholipase C; Phospholipids; Physiology; Potassium channels (voltage-gated); Protein Binding; Rapamycin; Science; Serotonin; Serotonin - pharmacology; Signal transduction; Signal Transduction - drug effects; Sirolimus - pharmacology; Translocation
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep23417

Voltage-gated e ther à go-go (EAG) K + channels are expressed in various types of cancer cells and also in the central nervous system. Aberrant overactivation of human EAG1 (hEAG1) channels is associated with cancer and neuronal disorders such as Zimmermann-Laband and Temple-Baraitser syndromes. Although hEAG1 channels are recognized as potential therapeutic targets, regulation of their functional properties is only poorly understood. Here, we show that the membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP 2 ) is a potent inhibitory gating modifier of hEAG1 channels. PIP 2 inhibits the channel activity by directly binding to a short N-terminal segment of the channel important for Ca 2+ /calmodulin (CaM) binding as evidenced by bio-layer interferometry measurements. Conversely, depletion of endogenous PIP 2 either by serotonin-induced phospholipase C (PLC) activation or by a rapamycin-induced translocation system enhances the channel activity at physiological membrane potentials, suggesting that PIP 2 exerts a tonic inhibitory influence. Our study, combining electrophysiological and direct binding assays, demonstrates that hEAG1 channels are subject to potent inhibitory modulation by multiple phospholipids and suggests that manipulations of the PIP 2 signaling pathway may represent a strategy to treat hEAG1 channel-associated diseases.