Premium
Identification of a Kv4 channel hydrophobic binding pocket for the inhibitory effects of polyunsaturated fatty acids
Author(s) -
Heler Robert,
Boland Linda M.,
Bell Jessica K.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1042.17
Subject(s) - polyunsaturated fatty acid , inhibitory postsynaptic potential , identification (biology) , chemistry , biochemistry , biology , fatty acid , botany , endocrinology
Polyunsaturated fatty acids such as arachidonic acid (AA) inhibit Kv4 potassium channel function and alter neuronal excitability. We tested the hypothesis that the inhibitory effects of AA on Kv4.2/KChIP channels require access to a hydrophobic binding site within a membrane‐embedded region of the channel. We prepared a homology model of Kv4.2 and used a molecular docking approach to identify residues that may interact with AA. The importance of each residue was tested by site‐directed mutagenesis and two‐microelectrode voltage clamp electrophysiology in Xenopus oocytes. Wild‐type currents were 30% inhibited by a 5 min exposure to 10 μM AA, applied externally. We identified several mutations that significantly impaired AA inhibition. We confirmed the molecular disruption of the AA binding pocket by simulating the mutagenic substitution in our Kv4.2 molecular model. Mutations introduced to residues located near but not within the putative binding pocket did not disrupt the fatty acid inhibition of Kv4.2 current, indicating the specificity of the residues which comprise the binding pocket. Our results suggest that AA may inhibit Kv4 channel function by interfering with the function of structural domains which are not in the permeation pathway. Funded by a grant from the Jeffress Foundation (LMB) and an APS Summer Undergraduate Fellowship (RH).