Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-59650
Elife 2023 Jan 04;12. doi: 10.7554/eLife.82479.
Show Gene links Show Anatomy links

Improved ANAP incorporation and VCF analysis reveal details of P2X7 current facilitation and a limited conformational interplay between ATP binding and the intracellular ballast domain.

Durner A , Durner E , Nicke A .


???displayArticle.abstract???
The large intracellular C-terminus of the pro-inflammatory P2X7 ion channel receptor (P2X7R) is associated with diverse P2X7R-specific functions. Cryo-EM structures of the closed and ATP-bound open full-length P2X7R recently identified a membrane-associated anchoring domain, an open-state stabilizing "cap" domain, and a globular "ballast domain" containing GTP/GDP and dinuclear Zn2+-binding sites with unknown functions. To investigate protein dynamics during channel activation, we improved incorporation of the environment-sensitive fluorescent unnatural amino acid L-3-(6-acetylnaphthalen-2-ylamino)-2-aminopropanoic acid (ANAP) into Xenopus laevis oocyte-expressed P2X7Rs and performed voltage clamp fluorometry. While we confirmed predicted conformational changes within the extracellular and the transmembrane domains, only 3 out of 41 mutants containing ANAP in the C-terminal domain resulted in ATP-induced fluorescence changes. We conclude that the ballast domain functions rather independently from the extracellular ATP binding domain and might require activation by additional ligands and/or protein interactions. Novel tools to study these are presented.

???displayArticle.pubmedLink??? 36598131
???displayArticle.pmcLink??? PMC9859053
???displayArticle.link??? Elife
???displayArticle.grants??? [+]

Species referenced: Xenopus laevis
Genes referenced: p2rx7
GO keywords: ion channel activity [+]

References [+] :
Allsopp, Contribution of the Juxtatransmembrane Intracellular Regions to the Time Course and Permeation of ATP-gated P2X7 Receptor Ion Channels. 2015, Pubmed, Xenbase