title: Depolarization increases phosphatidylinositol (PI) 4,5-bisphosphate level and KCNQ currents through PI 4-kinase mechanisms.
abstract: A growing body of evidence shows that membrane phosphatidylinositol 4,5-bisphosphates (PtdIns(4,5)P(2), PIP(2)) play an important role in cell signaling. The presence of PIP(2) is fundamentally important for maintaining the functions of a large number of ion channels and transporters, and for other cell processes such as vesicle trafficking, mobility, and endo- and exocytosis. PIP(2) levels in the membrane are dynamically modulated, which is an important signaling mechanism for modulation of PIP(2)-dependent cellular processes. In this study, we describe a novel mechanism of membrane PIP(2) modulation. Membrane depolarization induces an elevation in membrane PIP(2), and subsequently increases functions of PIP(2)-sensitive KCNQ potassium channels expressed in Xenopus oocytes. Further evidence suggests that the depolarization-induced elevation of membrane PIP(2) occurs through increased activity of PI4 kinase. With increased recognition of the importance of PIP(2) in cell function, the effect of membrane depolarization in PIP(2) metabolism is destined to have important physiological implications.
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
authors.forename: Xingjuan
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
authors.forename: Caixia
authors.initials: C
authors.lastname: Jia
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Geng
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
authors.forename: Xiaona
authors.initials: X
authors.lastname: Du
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, China. Electronic address: z_hailin@hotmail.com.
authors.forename: Hailin
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002855:Chromatography, Thin Layer / Q000379:methods; D004705:Endocytosis; D005089:Exocytosis; D015640:Ion Channel Gating; D051656:KCNQ Potassium Channels / Q000378:metabolism*; D008564:Membrane Potentials; D015778:Minor Histocompatibility Antigens; D008954:Models, Biological; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000737:chemistry; D015398:Signal Transduction; D014982:Xenopus laevis
chemical_list: D051656:KCNQ Potassium Channels; D015778:Minor Histocompatibility Antigens; D019269:Phosphatidylinositol 4,5-Diphosphate; D012330:RNA, Double-Stranded; D017853:Phosphotransferases (Alcohol Group Acceptor); C402182:phosphatidylinositol phosphate 4-kinase