title: Regulation of dendritic excitability by activity-dependent trafficking of the A-type K+ channel subunit Kv4.2 in hippocampal neurons.
abstract: Voltage-gated A-type K+ channel Kv4.2 subunits are highly expressed in the dendrites of hippocampal CA1 neurons. However, little is known about the subcellular distribution and trafficking of Kv4.2-containing channels. Here we provide evidence for activity-dependent trafficking of Kv4.2 in hippocampal spines and dendrites. Live imaging and electrophysiological recordings showed that Kv4.2 internalization is induced rapidly upon glutamate receptor stimulation. Kv4.2 internalization was clathrin mediated and required NMDA receptor activation and Ca2+ influx. In dissociated hippocampal neurons, mEPSC amplitude depended on functional Kv4.2 expression level and was enhanced by stimuli that induced Kv4.2 internalization. Long-term potentiation (LTP) induced by brief glycine application resulted in synaptic insertion of GluR1-containing AMPA receptors along with Kv4.2 internalization. We also found evidence of Kv4.2 internalization upon synaptically evoked LTP in CA1 neurons of hippocampal slice cultures. These results present an additional mechanism for synaptic integration and plasticity through the activity-dependent regulation of Kv4.2 channel surface expression.
authors.affiliation: Molecular Neurophysiology and Biophysics Unit, Laboratory of Cellular and Synaptic Neurophysiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA. kimji@mail.nih.gov
authors.forename: Jinhyun
authors.initials: J
authors.lastname: Kim
authors.forename: Sung-Cherl
authors.initials: SC
authors.lastname: Jung
authors.forename: Ann M
authors.initials: AM
authors.lastname: Clemens
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Petralia
authors.forename: Dax A
authors.initials: DA
authors.lastname: Hoffman
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D002966:Clathrin / Q000378:metabolism; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D004622:Embryo, Mammalian; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D005998:Glycine / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D016297:Mutagenesis, Site-Directed / Q000379:methods; D009474:Neurons / Q000166:cytology* / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D026902:Potassium Channel Blockers / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D051672:Shal Potassium Channels / Q000235:genetics / Q000378:metabolism*; D014161:Transduction, Genetic / Q000379:methods; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
chemical_list: D000199:Actins; D002966:Clathrin; D018690:Excitatory Amino Acid Agonists; D026902:Potassium Channel Blockers; D051672:Shal Potassium Channels; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D005998:Glycine