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The Rotavirus NSP4 Viroporin Domain is a Calcium-conducting Ion Channel
Thieng Pham1, Jacob L Perry2, Timothy L Dosey3
1Department of Biology and Biochemistry, University of Houston, Houston, TX, USA.
Scientific Reports
|March 4, 2017
Summary
Rotavirus nonstructural protein 4 (NSP4) viroporin domain forms an ion channel. This channel conducts calcium ions, explaining how NSP4 disrupts host cell calcium homeostasis crucial for viral replication.
Area of Science:
- Virology
- Molecular Biology
- Biophysics
Background:
- Viroporins are virus-encoded ion channels impacting host cell functions.
- Some viroporins disrupt calcium (Ca2+) homeostasis, essential for viral replication.
- Rotavirus nonstructural protein 4 (NSP4) is a transmembrane glycoprotein with a viroporin domain (VPD).
Purpose of the Study:
- To confirm the NSP4 viroporin domain (VPD) forms an ion channel.
- To determine if the NSP4 VPD can conduct calcium (Ca2+) ions.
Main Methods:
- Planar lipid bilayer and liposome patch clamp electrophysiology.
- Analysis of ion channel activity using synthetic peptides of the NSP4 VPD.
Main Results:
- A synthetic NSP4 VPD peptide exhibited ion channel activity.
- The channel was cation-selective and displayed typical viroporin current fluctuations.
- NSP4 VPD showed significant conductivity for Ca2+ and Ba2+, similar to K+, while a mutant lacked Ca2+ conductivity.
Conclusions:
- The NSP4 viroporin domain (VPD) functions as a Ca2+-conducting ion channel.
- This Ca2+ conductivity mechanism underlies NSP4's disruption of host cell Ca2+ homeostasis.
- Findings provide insight into rotavirus pathogenesis and host-pathogen interactions.
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