Function
P2X receptors are ATP-gated ion channels that play a role in intracellular calcium signaling. Not required for the purinergic response to extracellular nucleotides. Inward currents evoked by intracellular ATP and ATP analogs. Exclusively selective for ATP over other nucleotides. Insensitive to P2 receptor antagonists PPADS, suramin and 2',3'-O-(2,4,6-trinitrophenyl)-ATP but inhibited by nanomolar concentrations of copper and sodium ion. More permeable to ammonium than either sodium or potassium ions and less permeable to choline. It has been reported that p2xA is not essential for osmoregulation (PubMed:19833731), however this information is in contradiction with another source (PubMed:17625565) which indicates that p2xA is required for osmoregulation. Found to be permeable to chloride ions. Inhibited by copper and sodium ions.
Sequence
MGFSFDWDDIFQYSTVKIVRIRDRRLGILHLSFLVGIVAYIVVYSAIIKKGYLFTEVPIGSVRTSLKGPNTFASNLTYCSNQQHNGSTYPFTPLECNYWDEQLALFPVGQDSTFTCTTRVRLSKQEANCNFTDPTCKFVDEPGSAKNIYIADIESFTILIDHTMYASSSGSQFNAVDLHGYILNQDGDEVQIDANGTSIGVSGKPDIMTIGQLLSFGGVSLDQASPVDSNVSIRYDGVVLFVFITYSNTYTYSTSDFKYVYSVQQIANTIYDVPETIILESIHSRLLYKRHGIRVIFIQTGTIGSFHFQTLLLTLVSGLGLLAVATTVVDQLAIRLLPQRKSYSSLKFQVTESMSNPMKKRITTDEGEDVLYTRIEGL