Neuronal transmission stimulates the phosphorylation of Kv1.4 channel at Ser229 through protein kinase A1.
Phosphorylation of voltage-gated K+ channels (Kv) is involved in regulation of neuronal excitability, synaptic plasticity and neuronal survival. Among Kv channels expressed in the CNS, Kv1.4 is located in the soma, dendrite and axon terminus of neurones in most regions of the brain. Here, we show that Ser229 found within the highly conserved T1 domain of Kv1.4 in cultured rat cortical neurones is phosphorylated by protein kinase A (PKA), as demonstrated by in vitro protein kinase assay and Western blotting with a polyclonal antibody specific against phosphorylated Ser229. Glutamate, high concentrations of K+ or K+ channel blockers known to increase neurotransmission all stimulated the phosphorylation of Kv1.4 at Ser229 via N-methyl-D-aspartate (NMDA), but not alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA) receptor, whereas tetradotoxin (TTX), known to block neuronal transmission, and depletion of extracellular Ca2+ inhibited phosphorylation induced by tetraethylammonium (TEA), a non-selective K+ channel blocker. Mutation of Ser229 to Ala229 enhanced the current density. Taken together, elevation of the neuronal transmission stimulates the phosphorylation of Kv1.4 at Ser229 via the Ca2+ influx through NMDA receptor. Thus, it is possible that neuronal transmission regulates neuronal excitability partially through the phosphorylation of Kv1.4S229.
Institute of Neuroscience, Shanghai Institutes of Biological Sciences, Graduate School of Chinese Academy of Sciences, Shanghai, PR China.
Yanmei
Y
Tao
Rui
R
Zeng
Bin
B
Shen
Jiemin
J
Jia
Yizheng
Y
Wang
D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology; D002460:Cell Line; D002478:Cells, Cultured; D017124:Conserved Sequence / Q000187:drug effects / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D051665:Kv1.4 Potassium Channel; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
C496977:KCNA4 protein, human; C496979:Kcna4 protein, rat; D051665:Kv1.4 Potassium Channel; D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D016194:Receptors, N-Methyl-D-Aspartate; D026941:Sodium Channel Blockers; D018698:Glutamic Acid; D012694:Serine; D017868:Cyclic AMP-Dependent Protein Kinases; D011188:Potassium