Topological analysis of the ATP-gated ionotropic [correction of ionotrophic] P2X2 receptor subunit.
We investigated the transmembrane topology of the P2X2 receptor subunit expressed in HEK 293 cells. Initial studies using two P2X subunits expressed in tandem indicated that the amino- and carboxy-termini are on the same side of the membrane. Immunofluorescence studies showed the cytoplasmic orientation of the amino- and carboxy-termini. Finally, N-glycosylation scanning mutagenesis revealed that reporter sites inserted into the central loop, but not those in the amino- or carboxy-terminal regions, were glycosylated, thus suggesting an extracellular placement for that domain. Our results support a two-transmembrane arrangement for P2X receptors with intracellular amino- and carboxy-termini.
Torres
G E
GE
Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, MO 63104, USA.
Egan
T M
TM
Voigt
M M
MM
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D018076:DNA, Complementary; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D011487:Protein Conformation; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D058476:Receptors, Purinergic P2X2
D018076:DNA, Complementary; D008565:Membrane Proteins; C546401:P2RX2 protein, human; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate