title: Human EAG channels are directly modulated by PIP2 as revealed by electrophysiological and optical interference investigations.
abstract: Voltage-gated ether 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 (PIP2) is a potent inhibitory gating modifier of hEAG1 channels. PIP2 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 PIP2 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 PIP2 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 PIP2 signaling pathway may represent a strategy to treat hEAG1 channel-associated diseases.
authors.affiliation: Key Laboratory of Systems Biomedicine (Ministry of Education), Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Han
authors.affiliation: Key Laboratory of Systems Biomedicine (Ministry of Education), Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Kunyan
authors.initials: K
authors.lastname: He
authors.affiliation: Key Laboratory of Systems Biomedicine (Ministry of Education), Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Chunlin
authors.initials: C
authors.lastname: Cai
authors.affiliation: Key Laboratory of Systems Biomedicine (Ministry of Education), Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Key Laboratory of Systems Biomedicine (Ministry of Education), Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Linli
authors.initials: L
authors.lastname: Yang
authors.affiliation: Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena &Jena University Hospital, Hans-Knöll-Str. 2, D-07745 Jena, Germany.
authors.forename: Stefan H
authors.initials: SH
authors.lastname: Heinemann
authors.affiliation: Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Hoshi
authors.affiliation: Key Laboratory of Systems Biomedicine (Ministry of Education), Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China.|Tongren Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China.|State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Shangwei
authors.initials: S
authors.lastname: Hou
mesh_terms: D001665:Binding Sites; D002147:Calmodulin / Q000378:metabolism*; D055724:Electrophysiological Phenomena; D051638:Ether-A-Go-Go Potassium Channels / Q000737:chemistry* / Q000378:metabolism*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D018613:Microscopy, Confocal; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D011485:Protein Binding; D012701:Serotonin / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D051638:Ether-A-Go-Go Potassium Channels; C496884:KCNH1 protein, human; D019269:Phosphatidylinositol 4,5-Diphosphate; D012701:Serotonin; D020123:Sirolimus