Activity dependent plasma membrane insertion and internalization of Kv4.2 potassium channels in cultured hippocampal neurons

Evgeny Pryazhnikov, S Khiroug, Sarah Kate Coleman, Kari Keinänen, A Jeromin, Leonard Khirug

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

Abstract

The Kv4.2-containing potassium channels are generally considered to underlie the A-type current and counteract the depolarizing action of AMPA receptors by repolarizing neuronal membrane and decreasing firing frequency. However the precise mechanisms of Kv4.2 membrane trafficking are largely unknown. We studied trafficking of pHluorin- tagged Kv4.2 subunit in cultured hippocampal neurons using Total Internal Reflection Fluorescence (TIRF) microscopy. This imaging method was improved by supplementing with a repetitive acidification protocol. We found that brief activation of NMDA receptors (“chemical LTP”) in cultured hippocampal neurons induced a transient plasma membrane insertion of the potassium channels containing pHluorin-Kv4.2, which was followed by their internalization. Truncation of PDZ-binding motif in the intracellular C-terminus of Kv4.2 did not disrupt constitutive trafficking of pHluorin-Kv4.2 channels to PM. However, activation of NMDA receptors failed to induce membrane insertion of the truncated Kv4.2 channels; instead, internalization of existing PM-inserted truncated Kv4.2 channels was observed. We suggest that the complex behaviour of activity-dependent Kv4.2 trafficking may fine-tune the balance between NMDA-receptor dependent and independent forms of long-term synaptic plasticity.
Original languageEnglish
Title of host publicationAbstract book of 39th SfN annual meeting
Publication dateOct 2009
Publication statusPublished - Oct 2009
MoE publication typeB3 Article in conference proceedings
Event39th SfN annual meeting - Chicago, United States
Duration: 17 Oct 201021 Oct 2010

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