Roles of conserved ectodomain cysteines of the rat P2X4 purinoreceptor in agonist binding and channel gating

Title:

Roles of conserved ectodomain cysteines of the rat P2X4 purinoreceptor in agonist binding and channel gating

Creator:

Rokic, M. B., Tvrdoňová, V., Vojtěch Vávra, Marie Jindřichová, Tomáš Obšil, Stanko S. Stojilković, and Hana Zemková

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:33b1aeaf-c847-437b-ad98-dbc0e6c841aa
uuid:33b1aeaf-c847-437b-ad98-dbc0e6c841aa
issn:0862-8408

Subject:

Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, Purinergic signaling, ATP-gated receptor-channels, Disulfide bonds, Ivermectin, Deactivation, 14, and 612

Type:

article, články, model:article, and TEXT

Format:

print, bez média, and svazek

Description:

Mammalian P2X receptors contain 10 conserved cysteine residues in their ectodomains, which form five disulfide bonds (SS1-5). Here, we analyzed the relevance of these disulfide pairs in rat P2X4 receptor function by replacing one or both cysteines with alanine or threonine, expressing receptors in HEK293 cells and studying their responsiveness to ATP in the absence and presence of ivermectin, an allostenic modulator of these channels. Response to ATP was not altered when both cysteines forming the SS3 bond (C132-C159) were replaced with threonines. Replacem ent of SS1 (C116-C165), SS2 (C126-C149) and SS4 (C217-C227), but not SS5 (C261-C270), cysteine pairs with threonines resulted in de creased sensitivity to ATP and faster deactivation times. The maximum current amplitude was reduced in SS2, SS4 and SS5 double mutants and could be partially rescued by ivermectin in SS2 and SS5 double mutants. This response pattern was also observed in numerous single residue mutants, but receptor function was not affected when the 217 cysteine was replaced with threonine or arginine or when the 261 cysteine was replaced with alanine. These results suggest that the SS1, SS2 and SS4 bonds contribute substantially to the structure of the ligand binding pocket, while the SS5 bond located towards the transmembrane domain contributes to receptor gating., M. B. Rokic, V. Tvrdoňová, V. Vávra, M. Jindřichová, T. Obšil, S. S. Stojilkovic, H. Zemková., and Obsahuje bibliografii

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Source:

Physiological research | 2010 Volume:59 | Number:6

Harvested from:

CDK

Metadata only:

false