title: The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels contain multiple S-palmitoylation sites.
abstract: Expression of hyperpolarization-activated cyclic nucleotide-gated channels (HCN1-4) on distal dendrites of neurons is suggested to modify synaptic integration in the central nervous system. However, the mechanisms of dendritic localization are not fully understood. Recent studies have revealed that S-palmitoylation plays an important role in the enrichment of various molecules at the postsynaptic membrane. Thus, we performed an acyl-biotinyl exchange assay, and found that HCN1, HCN2, and HCN4, but not HCN3, were S-palmitoylated in HEK293 cells. Mutation of multiple intracellular cysteine residues at the N-terminus of HCN2 was required for complete inhibition of S-palmitoylation. However, this mutagenesis had a minimal effect on surface expression of HCN2 proteins or electrophysiological properties of HCN2 current when expressed in HEK293 cells or in Xenopus oocytes. These findings provide insight into the physiological roles of S-palmitoylation of HCN channels in native neurons.
authors.affiliation: Division of Integrated Autonomic Function, Department of Physiology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka, 830-0011, Japan. mitoh@med.kurume-u.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Itoh
authors.affiliation: Division of Integrated Autonomic Function, Department of Physiology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka, 830-0011, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Ishihara
authors.affiliation: Department of Physiology, Faculty of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, 606-8501, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nakashima
authors.affiliation: Division of Integrated Autonomic Function, Department of Physiology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka, 830-0011, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Takano
mesh_terms: D000818:Animals; D019921:Biotinylation; D057809:HEK293 Cells / Q000502:physiology; D006801:Humans; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / Q000737:chemistry / Q000502:physiology*; D009124:Muscle Proteins / Q000737:chemistry / Q000502:physiology; D009865:Oocytes / Q000502:physiology; D019308:Palmitic Acid / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000737:chemistry / Q000502:physiology; D014981:Xenopus
chemical_list: C578665:HCN1 protein, human; C578710:HCN2 protein, human; C472018:HCN3 protein, human; C119587:HCN4 protein, human; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D009124:Muscle Proteins; D015221:Potassium Channels; D019308:Palmitic Acid
keywords: Acyl-biotinyl exchange assay; Hyperpolarization-activated cyclic nucleotide-gated channel; Post-translational modifications; S-palmitoylation