title: Protein kinase a mediates activity-dependent Kv4.2 channel trafficking.
abstract: The A-type potassium channel subunit Kv4.2 influences hippocampal function through regulation of dendritic excitability, and changes in Kv4.2 surface expression alter synaptic plasticity. Recent data from our laboratory demonstrate that EGFP (enhanced green fluorescent protein)-tagged Kv4.2 channels located in dendritic spines are internalized in an activity-dependent manner after synaptic stimulation and during chemically induced long-term potentiation. However, the molecular trigger for Kv4.2 internalization remains unknown. Here we examined the role of protein kinase A (PKA) in Kv4.2 activity-dependent trafficking. In hippocampal neurons, PKA activation with forskolin or 8-Br-cAMP induced Kv4.2 internalization from dendritic spines, whereas PKA inhibition with H89 prevented AMPA-induced internalization. Furthermore, introduction of a point mutation at the C-terminal PKA phosphorylation site of Kv4.2 (S552A) prevented the AMPA-induced internalization of Kv4.2. Together, these data demonstrate that Kv4.2 activity-dependent internalization requires PKA phosphorylation of Kv4.2 at serine 522.
authors.affiliation: Laboratory of Cellular and Synaptic Neurophysiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-3715, USA.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Hammond
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.forename: Michael S
authors.initials: MS
authors.lastname: Sidorov
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Wikenheiser
authors.forename: Dax A
authors.initials: DA
authors.lastname: Hoffman
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000409:Alanine / Q000235:genetics; D000818:Animals; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006624:Hippocampus / Q000166:cytology; D007546:Isoquinolines / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012694:Serine / Q000235:genetics; D051672:Shal Potassium Channels / Q000235:genetics / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D014162:Transfection / Q000379:methods; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D007546:Isoquinolines; D051672:Shal Potassium Channels; D013449:Sulfonamides; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D012694:Serine; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D017868:Cyclic AMP-Dependent Protein Kinases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D000409:Alanine