Journal Article

FZJ-2018-06528

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The Conorfamide RPRFa Stabilizes the Open Conformation of Acid-Sensing Ion Channel 3 via the Nonproton Ligand–Sensing Domain

Reiners, M. ; Margreiter, M. A. ; Oslender-Bujotzek, A. ; Rossetti, G.FZJ* ; Gründer, S. (Corresponding author) ; Schmidt, A. (Corresponding author)

2018
ASPET Bethesda, Md.

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Please use a persistent id in citations: doi:10.1124/mol.118.112375

Abstract: Acid-sensing ion channel 3 (ASIC3) is a proton-gated Na+ channel with important roles in pain. ASIC3 quickly desensitizes in less than a second, limiting its capacity to sense sustained acidosis during pain. RFamide neuropeptides are modulators of ASIC3 that slow its desensitization and induce a variable sustained current. The molecular mechanism of slowed desensitization and the RFamide binding site on ASIC3 are unknown. RPRFamide, a RFamide from the venom of a cone snail, has a comparatively high affinity for ASIC3 and strongly slows its desensitization. Here we show that covalent binding of a UV-sensitive RPRFamide variant to ASIC3 prevents desensitization, suggesting that RPRFamide has to unbind from ASIC3 before it can desensitize. Moreover, we show by in silico docking to a homology model of ASIC3 that a cavity in the lower palm domain, which is also known as the nonproton ligand–sensing domain, is a potential binding site of RPRFamide. Finally, using extensive mutagenesis of residues lining the nonproton ligand–sensing domain, we confirm that this domain is essential for RPRFamide modulation of ASIC3. As comparative analysis of ASIC crystal structures in the open and in the desensitized conformation suggests that the lower palm domain contracts during desensitization, our results collectively suggest that RPRFamide, and probably also other RFamide neuropeptides, bind to the nonproton ligand–sensing domain to stabilize the open conformation of ASIC3.

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Contributing Institute(s):

1. Computational Biomedicine (IAS-5)
2. Computational Biomedicine (INM-9)
3. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 574 - Theory, modelling and simulation (POF3-574) (POF3-574)
2. 511 - Computational Science and Mathematical Methods (POF3-511) (POF3-511)

Appears in the scientific report 2018

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Database coverage:
; BIOSIS Previews ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; PubMed Central ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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