TY  - JOUR
A1  - Rettinger, Jürgen
A1  - Aschrafi, Armaz
A1  - Schmalzing, Günther
T1  - Roles of individual N-glycans for ATP potency and expression of the rat P2X1 receptor
T2  - The journal of biological chemistry
N2  - P2X1 receptor subunits assemble in the ER of Xenopus oocytes to homotrimers that appear as ATP-gated cation channels at the cell surface. Here we address the extent to which N-glycosylation contributes to assembly, surface appearance, and ligand recognition of P2X1receptors. SDS-polyacrylamide gel electrophoresis (PAGE) analysis of glycan minus mutants carrying Gln instead of Asn at five individual NXT/S sequons reveals that Asn284 remains unused because of a proline in the +4 position. The four other sites (Asn153, Asn184, Asn210, and Asn300) carryN-glycans, but solely Asn300 located only eight residues upstream of the predicted reentry loop of P2X1acquires complex-type carbohydrates. Like parent P2X1, glycan minus mutants migrate as homotrimers when resolved by blue native PAGE. Recording of ATP-gated currents reveals that elimination of Asn153 or Asn210 diminishes or increases functional expression levels, respectively. In addition, elimination of Asn210 causes a 3-fold reduction of the potency for ATP. If three or all four N-glycosylation sites are simultaneously eliminated, formation of P2X1 receptors is severely impaired or abolished, respectively. We conclude that at least oneN-glycan per subunit of either position is absolutely required for the formation of P2X1 receptors and that individual N-glycans possess marked positional effects on expression levels (Asn154, Asn210) and ATP potency (Asn210).
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/75854
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-758541
SN  - 0021-9258
VL  - 275.
IS  - 43
SP  - 33542
EP  - 33547
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -