[Abstract Title]. - Society for Neuroscience

Program#/Poster#: 234.4/C28
Topic: B.04.c. Potassium channels: Physiology
Support: Grants-in-Aid from the Ministry of Education, Culture, Sports, Science and
Technology of Japan
Keio Gijuku Academic Development Funds
Kanehara Foundation Research Grant
Title: Regulation of Kv4.2 by neuronal activity
Authors: *M. NURIYA, T. ITO, M. YASUI;
Pharmacol, Keio Univ., Shinjuku, Japan
Abstract: Voltage gated ion channels are crucial to neuronal functions both in physiological and
pathological conditions. Kv4.2 constitutes a major component of A-type potassium current and is
localized specifically at dendrites and soma, where it plays critical roles in propagations of
voltage information by regulating the excitability of dendrites. While functional modifications of
Kv4.2 by its phosphorylations through several signal transduction pathways have been described,
physiological stimuli that modify these phosphorylation states remain mostly unknown. Here, we
report that neuronal activity induces rapid and specific dephosphorylation of Kv4.2 in primary
cultured cortical neurons. Activation of N-methyl-D-aspartic acid (NMDA) receptor but not αamino-3-hydroxy-5-methylisoxazole-4-propionic
acid (AMPA) receptor is necessary and
sufficient for this dephosphorylation. As bulk calcium influx by ionomycin does not mimic this
NMDA receptor activation effect, some specific signal transductions other than a mere rise of
cytoplasmic calcium concentration appear to be responsible for this rapid dephosphorylation of
Kv4.2. Finally, this reaction occurs both at the plasma membrane as well as inside the cell and
does not change surface expression level of Kv4.2 by itself. These data indicate that Kv4.2
phosphorylation is dynamically regulated in neurons and that neuronal activity and following
activation of NMDA receptor is a strong regulator of Kv4.2. This activity dependent
modification of Kv4.2 may underlie activity-dependent changes of dendritic excitability under
physiological conditions.
Disclosures: M. Nuriya, None; T. Ito, None; M. Yasui, None.
Poster
234. A-Type Potassium Channels
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm