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Modulation of the frequency response of Shaker potassium channels by the quiver peptide suggesting a novel extracellular interaction mechanism
Journal article   Peer reviewed

Modulation of the frequency response of Shaker potassium channels by the quiver peptide suggesting a novel extracellular interaction mechanism

Jing W Wang and Chun-Fang Wu
Journal of neurogenetics, Vol.24(2), pp.67-74
07/2010
DOI: 10.3109/01677061003746341
PMCID: PMC3115930
PMID: 20429677
url
https://www.ncbi.nlm.nih.gov/pmc/articles/3115930View
Open Access

Abstract

Recent studies have indicated that the Shaker potassium channel regulates sleep in Drosophila. The Drosophila quiver (qvr) gene encodes a novel potassium channel subunit that modulates the Shaker potassium channel. The Qvr peptide contains a signal sequence for extracellular localization and may regulate a unique feature of the Shaker I(A) current that confers special neuronal excitability patterns. Thus, studies of the Shaker channel properties in the qvr mutant background should provide an opportunity to uncover a new form of physiologic modulation of potassium channels. We have begun to investigate the impact of qvr protein on the Shaker channel properties and its implications in synaptic function in vivo. We studied synaptic transmission at the larval neuromuscular junction and characterized the transient potassium current I(A) in larval muscles. We identified two different functional states of I(A) in qvr larval muscles, as reflected by two distinct components, I(AF) and I(AS), differing in their kinetics of recovery from inactivation and sensitivity to a K(+) channel blocker. Correspondingly, qvr mutant larvae exhibit multiple synaptic discharges following individual nerve stimuli during repetitive activity.
Shaker Superfamily of Potassium Channels - antagonists & inhibitors Synaptic Transmission - physiology Recovery of Function - drug effects Synaptic Transmission - genetics Neuromuscular Junction - metabolism Shaker Superfamily of Potassium Channels - metabolism Potassium Channels - physiology Extracellular Space - genetics Neuropeptides - physiology Drosophila Proteins - metabolism Excitatory Postsynaptic Potentials - drug effects Potassium Channel Blockers - metabolism Protein Subunits - metabolism Potassium Channels - metabolism Drosophila Proteins - physiology Extracellular Space - metabolism Neuromuscular Junction - genetics Larva - genetics Neuropeptides - genetics Protein Subunits - physiology Drosophila Proteins - antagonists & inhibitors 4-Aminopyridine - pharmacology Excitatory Postsynaptic Potentials - genetics Organ Culture Techniques Potassium Channel Blockers - pharmacology Protein Subunits - genetics Extracellular Space - physiology Recovery of Function - genetics Shaker Superfamily of Potassium Channels - genetics Larva - metabolism Mutation - genetics Potassium Channels - genetics Animals Drosophila Proteins - genetics Kinetics Drosophila melanogaster

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