Down-Regulation of Inwardly Rectifying Kir2.1K+ Channels by Human Parvovirus B19 Capsid Protein VP1

Down-Regulation of Inwardly Rectifying Kir2.1K+ Channels by Human Parvovirus B19 Capsid Protein VP1 Parvovirus B19 (B19V) has previously been shown to cause endothelial dysfunction. B19V capsid protein VP1 harbors a lysophosphatidylcholine producing phospholipase A2 (PLA2). Lysophosphatidylcholine inhibits Na+/K+ ATPase, which in turn may impact on the activity of inwardly rectifying K+ channels. The present study explored whether VP1 modifies the activity of Kir2.1 K+ channels. cRNA encoding Kir2.1 was injected into Xenopus oocytes without or with cRNA encoding VP1 isolated from a patient suffering from fatal B19V-induced inflammatory cardiomyopathy or the VP1 mutant H153AVP1 lacking a functional PLA2 activity. K+ channel activity was determined by dual electrode voltage clamp. In addition, Na+/K+-ATPase activity was estimated from K+-induced pump current (I pump) and ouabain-inhibited current (I ouabain). Injection of cRNA encoding Kir2.1 into Xenopus oocytes was followed by appearance of inwardly rectifying K+ channel activity (I K), which was significantly decreased by additional injection of cRNA encoding VP1, but not by additional injection of cRNA encoding H153AVP1. The effect of VP1 on I K was mimicked by lysophosphatidylcholine (1 μg/ml) and by inhibition of Na+/K+-ATPase with 0.1 mM ouabain. In the presence of lysophosphatidylcholine, I K was not further decreased by additional treatment with ouabain. The B19V capsid protein VP1 thus inhibits Kir2.1 channels, an effect at least partially due to PLA2-dependent formation of lysophosphatidylcholine with subsequent inhibition of Na+/K+-ATPase activity. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Down-Regulation of Inwardly Rectifying Kir2.1K+ Channels by Human Parvovirus B19 Capsid Protein VP1

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Publisher
Springer US
Copyright
Copyright © 2014 by Springer Science+Business Media New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-014-9762-9
Publisher site
See Article on Publisher Site

Abstract

Parvovirus B19 (B19V) has previously been shown to cause endothelial dysfunction. B19V capsid protein VP1 harbors a lysophosphatidylcholine producing phospholipase A2 (PLA2). Lysophosphatidylcholine inhibits Na+/K+ ATPase, which in turn may impact on the activity of inwardly rectifying K+ channels. The present study explored whether VP1 modifies the activity of Kir2.1 K+ channels. cRNA encoding Kir2.1 was injected into Xenopus oocytes without or with cRNA encoding VP1 isolated from a patient suffering from fatal B19V-induced inflammatory cardiomyopathy or the VP1 mutant H153AVP1 lacking a functional PLA2 activity. K+ channel activity was determined by dual electrode voltage clamp. In addition, Na+/K+-ATPase activity was estimated from K+-induced pump current (I pump) and ouabain-inhibited current (I ouabain). Injection of cRNA encoding Kir2.1 into Xenopus oocytes was followed by appearance of inwardly rectifying K+ channel activity (I K), which was significantly decreased by additional injection of cRNA encoding VP1, but not by additional injection of cRNA encoding H153AVP1. The effect of VP1 on I K was mimicked by lysophosphatidylcholine (1 μg/ml) and by inhibition of Na+/K+-ATPase with 0.1 mM ouabain. In the presence of lysophosphatidylcholine, I K was not further decreased by additional treatment with ouabain. The B19V capsid protein VP1 thus inhibits Kir2.1 channels, an effect at least partially due to PLA2-dependent formation of lysophosphatidylcholine with subsequent inhibition of Na+/K+-ATPase activity.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Dec 9, 2014

References

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