Ca²⁺ flux through splice variants of the ATP-gated ionotropic receptor P2X7 is regulated by its cytoplasmic N terminus.

ABSTRACT: Activation of ionotropic P2X receptors increases free intracellular Ca²⁺ ([Ca²⁺] _i ) by initiating a transmembrane cation flux. We studied the "a" and "k" splice variants of the rat purinergic P2X7 receptor (rP2X7aR and rP2X7kR) to exhibit a significant difference in Ca²⁺ flux through this channel. This difference is surprising because the variants share absolute sequence identity in the area of the pore that defines ionic selectivity. Here, we used patch-clamp fluorometry and chimeric receptors to show that the fraction of the total current carried by Ca²⁺ is a function of the primary sequence of the cytoplasmic N terminus. Using scanning mutagenesis, we identified five sites within the N terminus that respond to mutagenesis wi

SUBMITTER: Liang X 

PROVIDER: S-EPMC6699846 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature