title: Gating charge movement precedes ionic current activation in hERG channels.
abstract: We recently reported gating currents recorded from hERG channels expressed in mammalian TSA cells and assessed the kinetics at different voltages. We detected 2 distinct components of charge movement with the bulk of the charge being carried by a slower component. Here we compare our findings in TSA cells with recordings made from oocytes using the Cut Open Vaseline Gap clamp (COVG) and go on to directly compare activation of gating charge and ionic currents at 0 and +60 mV. The data show that gating charge saturates and moves more rapidly than ionic current activates suggesting a transition downstream from the movement of the bulk of gating charge is rate limiting for channel opening.
authors.affiliation: Department of Anesthesiology, Pharmacology and Therapeutics; University of British Columbia; Vancouver, BC Canada.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Goodchild
authors.affiliation: Department of Anesthesiology, Pharmacology and Therapeutics; University of British Columbia; Vancouver, BC Canada.
authors.forename: David
authors.initials: D
authors.lastname: Fedida
mesh_terms: D002478:Cells, Cultured; D051638:Ether-A-Go-Go Potassium Channels / Q000502:physiology*; D006801:Humans; D015640:Ion Channel Gating; D009865:Oocytes / Q000502:physiology; D018408:Patch-Clamp Techniques
chemical_list: D051638:Ether-A-Go-Go Potassium Channels
keywords: activation; gating currents; hERG; kinetics; potassium channel