title: Identification and characterization of small molecule modulators of KChIP/Kv4 function.
abstract: Potassium channels and their associated subunits are important contributors to electrical excitability in many cell types. In this study, a yeast two-hybrid assay was used to identify inhibitors such as a diaryl-urea compound (CL-888) that binds to and modulates the formation of the Kv4/KChIP complex. CL-888 altered the apparent affinity of KChIP1 to Kv4.3-N in a Biacore assay, but did not dissociate the two proteins in size-exclusion chromatography experiments. Kv4.2/KChIP1 current amplitude and kinetics were altered with compound exposure, supporting the hypothesis of a compound-induced conformational change in the protein complex. Fluorescence spectroscopy of a unique tryptophan residue in KChIP1 was consistent with compound binding to the protein. Molecular modeling using the KChIP1 crystal structure indicates that compound binding may occur in a small tryptophan-containing binding pocket located on the hydrophilic side of the protein.
authors.affiliation: Discovery Neuroscience, Wyeth Research, CN 8000, Princeton, NJ 08543-8000, USA. bowlbym@wyeth.com
authors.forename: Mark R
authors.initials: MR
authors.lastname: Bowlby
authors.forename: Pranab
authors.initials: P
authors.lastname: Chanda
authors.forename: Wade
authors.initials: W
authors.lastname: Edris
authors.forename: Joseph
authors.initials: J
authors.lastname: Hinson
authors.forename: Flora
authors.initials: F
authors.lastname: Jow
authors.forename: Alan H
authors.initials: AH
authors.lastname: Katz
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kennedy
authors.forename: Girija
authors.initials: G
authors.lastname: Krishnamurthy
authors.forename: Keith
authors.initials: K
authors.lastname: Pitts
authors.forename: Kevin
authors.initials: K
authors.lastname: Ryan
authors.forename: Howard
authors.initials: H
authors.lastname: Zhang
authors.forename: Lynne
authors.initials: L
authors.lastname: Greenblatt
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D004594:Electrophysiology; D018014:Gene Transfer Techniques; D006801:Humans; D020128:Inhibitory Concentration 50; D051605:Kv Channel-Interacting Proteins / Q000235:genetics / Q000378:metabolism*; D008956:Models, Chemical; D008958:Models, Molecular; D009865:Oocytes / Q000502:physiology; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D051672:Shal Potassium Channels / Q000235:genetics / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D020798:Two-Hybrid System Techniques; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology; D014981:Xenopus
chemical_list: C507088:CL-888; D051605:Kv Channel-Interacting Proteins; D051672:Shal Potassium Channels; D014508:Urea